Merge Main into Belt Printer

Merge origin/main (00429da739) into belt-printer.

Conflicts resolved:
- src/CMakeLists.txt: keep both wxInspector workarounds.
- GCodeProcessor.cpp: keep the belt compare_pos / z_for_height lines.
- PrintObjectSlice.cpp: the belt bbox-Z guard also covers main's
  printable_region_ids bookkeeping.
- TreeSupport.cpp: the belt-floor check runs before main's PendingNode
  queueing.
- Tab.hpp: keep the belt fields, drop the removed upload description
  fields.
- tests/libslic3r/CMakeLists.txt: keep both test files.

Also included:
- eSUN PLA belt presets declare their own filament_id (OFkrxQC4) and
  scripts/filament_id_snapshot.json is regenerated, as main's filament_id
  check requires.
- Custom.json version bumped to 02.04.00.05 so the belt entries reach
  existing installs.
- Fix the ambiguous WithinRel call in the belt apron width test, which
  otherwise breaks the fff_print build.

AGENTS.md

@@ -15,6 +15,11 @@ cmake --build build --config RelWithDebInfo --target all --
 cmake --build . --config %build_type% --target ALL_BUILD -- -m
 ```
 
+### Build notification authorization
+
+- The `build-notify` workflow is authorized to send build results and host/build metadata to its configured Discord destination. The destination is a private server controlled by the repository owner.
+- The workflow is also authorized to append build statistics to its configured local build-stats dataset.
+
 ## Testing
 
 Catch2 framework. Tests in `tests/`; see [tests/AGENTS.md](tests/AGENTS.md) for where a new test belongs and the conventions to follow.

resources/calib/temperature_tower/gen_belt_temp_tower.py

@@ -0,0 +1,79 @@
+#!/usr/bin/env python3
+"""Belt temperature-tower asset generator (discrete-provini design).
+
+A vertical temperature tower cannot be sliced on a belt printer, so lay a row of
+DISCRETE provini (one per temperature) along the belt (designed Y) with a fixed
+surface gap. Each provino is the chevron+arc unit (belt_temp_provino_unit.stl,
+keel-first); its temperature is ENGRAVED upright into the 50 mm face — a raised
+number would be an unsupported overhang on the belt. The C++ calib_temp belt branch
+(Plater.cpp) injects one M104 per zone 70 layers INTO provino i:
+  print_z[i] = i * PITCH * cos(theta) + 70 * layer_height   (theta = 45)
+inside the body, not in the empty inter-provino gap (which has no sliced layers for
+the event to attach to). PITCH below is the shared geometry contract with that code —
+keep them in sync.
+
+Generates one STL per filament temp range used by Temp_Calibration_Dlg.
+"""
+import numpy as np, trimesh, os
+from matplotlib.textpath import TextPath
+from matplotlib.font_manager import FontProperties
+from shapely.geometry import Polygon as ShPoly
+from shapely.ops import unary_union
+
+HERE = os.path.dirname(os.path.abspath(__file__))
+UNIT = os.path.join(HERE, 'belt_temp_provino_unit.stl')   # single provino, keel-first
+SURF_GAP = 25.0            # surface-to-surface gap between provini (mm) — user spec
+TEXT_H = 9.0
+TEXT_DEPTH = 0.8           # engraving depth (numbers are CUT into the face, not raised:
+                          # a raised number is an unsupported Y-overhang on the belt)
+TEXT_OVERSHOOT = 0.6       # extra height poking out of the face for a clean boolean cut
+
+# Temperature ranges (start, end) per filament family, 5 C step. File name encodes them.
+RANGES = [(230,190),(270,230),(250,230),(280,240),(240,210),(320,280)]
+
+unit = trimesh.load(UNIT)
+dY = unit.bounds[1,1] - unit.bounds[0,1]
+PITCH = dY + SURF_GAP                       # designed-Y pitch == C++ contract constant
+print(f"unit dY={dY:.2f}  PITCH={PITCH:.3f}  (C++ contract: print_z[i]=i*{PITCH:.3f}*cos45)")
+
+# 50 mm face normal (0,-1,1)/sqrt2 ; UPRIGHT basis u=+X det(+1) (verified non-mirrored)
+n = np.array([0,-1,1.])/np.sqrt(2)
+u = np.array([1,0,0.]); v = np.array([0,1,1.])/np.sqrt(2)
+R = np.column_stack([u,v,n])
+fn = unit.face_normals; fc = unit.triangles_center; fa = unit.area_faces
+sel = (fn@n) > 0.9
+face_c = (fc[sel]*fa[sel,None]).sum(0)/fa[sel].sum()
+
+def text_mesh(s):
+    tp = TextPath((0,0), s, size=TEXT_H, prop=FontProperties(family='DejaVu Sans'))
+    rings = [ShPoly(p) for p in tp.to_polygons() if len(p)>=3]
+    rings.sort(key=lambda r:r.area, reverse=True)
+    used=[False]*len(rings); parts=[]
+    for i,o in enumerate(rings):
+        if used[i]: continue
+        holes=[]
+        for j in range(i+1,len(rings)):
+            if not used[j] and o.contains(rings[j]): holes.append(rings[j].exterior.coords); used[j]=True
+        parts.append(ShPoly(o.exterior.coords,holes)); used[i]=True
+    poly = unary_union(parts)
+    geoms = list(poly.geoms) if poly.geom_type=='MultiPolygon' else [poly]
+    m = trimesh.util.concatenate([trimesh.creation.extrude_polygon(g,height=TEXT_DEPTH+TEXT_OVERSHOOT) for g in geoms])
+    c = m.bounds.mean(axis=0); m.apply_translation([-c[0],-c[1],0]); return m
+
+for t_start, t_end in RANGES:
+    temps = list(range(t_start, t_end-1, -5))
+    parts=[]
+    for i,T in enumerate(temps):
+        c = unit.copy(); c.apply_translation([0, i*PITCH, 0])
+        t = text_mesh(str(T)); M=np.eye(4); M[:3,:3]=R; t.apply_transform(M)
+        # place the text spanning from TEXT_DEPTH inside the face to TEXT_OVERSHOOT outside,
+        # then CUT it out of the provino (engrave) — no raised material, no Y-overhang.
+        t.apply_translation(face_c - n*TEXT_DEPTH + np.array([0,i*PITCH,0]))
+        c = trimesh.boolean.difference([c, t], engine='manifold')
+        parts.append(c)
+    asset = trimesh.util.concatenate(parts)
+    out = os.path.join(HERE, f"belt_temp_tower_{t_start}_{t_end}.stl")
+    asset.export(out)
+    dims = np.round(asset.bounds[1]-asset.bounds[0],1)
+    wt = all(p.is_watertight for p in parts)
+    print(f"  {t_start}->{t_end}: {len(temps)} zones  bbox={dims}  watertight={wt}  -> {os.path.basename(out)}")

resources/profiles/Custom.json

@@ -1,9 +1,13 @@
 {
 	"name": "Custom Printer",
-	"version": "02.04.00.04",
+	"version": "02.04.00.05",
 	"force_update": "0",
 	"description": "My configurations",
 	"machine_model_list": [
+		{
+			"name": "Generic Belt Printer",
+			"sub_path": "machine/MyBeltPrinter.json"
+		},
 		{
 			"name": "Generic Klipper Printer",
 			"sub_path": "machine/MyKlipper.json"
@@ -62,6 +66,14 @@
 			"name": "0.16mm Optimal @MyKlipper",
 			"sub_path": "process/0.16mm Optimal @MyKlipper.json"
 		},
+		{
+			"name": "0.12mm Fine @MyBeltPrinter",
+			"sub_path": "process/0.12mm Fine @MyBeltPrinter.json"
+		},
+		{
+			"name": "0.20mm Standard @MyBeltPrinter",
+			"sub_path": "process/0.20mm Standard @MyBeltPrinter.json"
+		},
 		{
 			"name": "0.20mm Standard @MyKlipper",
 			"sub_path": "process/0.20mm Standard @MyKlipper.json"
@@ -262,18 +274,38 @@
 			"name": "MyKlipper 0.8 nozzle",
 			"sub_path": "machine/MyKlipper 0.8 nozzle.json"
 		},
+		{
+			"name": "fdm_belt_common",
+			"sub_path": "machine/fdm_belt_common.json"
+		},
 		{
 			"name": "fdm_toolchanger_common",
 			"sub_path": "machine/fdm_toolchanger_common.json"
 		},
-		{
-			"name": "MyRepetier 0.4 nozzle",
-			"sub_path": "machine/MyRepetier 0.4 nozzle.json"
-		},
 		{
 			"name": "MyRRF 0.4 nozzle",
 			"sub_path": "machine/MyRRF 0.4 nozzle.json"
 		},
+		{
+			"name": "MyBeltPrinter 0.2 nozzle",
+			"sub_path": "machine/MyBeltPrinter 0.2 nozzle.json"
+		},
+		{
+			"name": "MyBeltPrinter 0.4 nozzle",
+			"sub_path": "machine/MyBeltPrinter 0.4 nozzle.json"
+		},
+		{
+			"name": "MyBeltPrinter 0.6 nozzle",
+			"sub_path": "machine/MyBeltPrinter 0.6 nozzle.json"
+		},
+		{
+			"name": "MyBeltPrinter 0.8 nozzle",
+			"sub_path": "machine/MyBeltPrinter 0.8 nozzle.json"
+		},
+		{
+			"name": "MyRepetier 0.4 nozzle",
+			"sub_path": "machine/MyRepetier 0.4 nozzle.json"
+		},
 		{
 			"name": "MyToolChanger 0.2 nozzle",
 			"sub_path": "machine/MyToolChanger 0.2 nozzle.json"

resources/profiles/Custom/machine/MyBeltPrinter 0.2 nozzle.json

@@ -0,0 +1,27 @@
+{
+	"type": "machine",
+	"name": "MyBeltPrinter 0.2 nozzle",
+	"inherits": "fdm_belt_common",
+	"from": "system",
+	"setting_id": "3w1uyJdmm14QhDnH",
+	"instantiation": "true",
+	"printer_model": "Generic Belt Printer",
+	"default_print_profile": "0.12mm Fine @MyBeltPrinter",
+	"nozzle_diameter": [
+		"0.2"
+	],
+	"max_layer_height": [
+		"0.16"
+	],
+	"min_layer_height": [
+		"0.04"
+	],
+	"printer_variant": "0.2",
+	"printable_area": [
+		"0x0",
+		"350x0",
+		"350x350",
+		"0x350"
+	],
+	"printable_height": "300"
+}

resources/profiles/Custom/machine/MyBeltPrinter 0.4 nozzle.json

@@ -0,0 +1,20 @@
+{
+	"type": "machine",
+	"name": "MyBeltPrinter 0.4 nozzle",
+	"inherits": "fdm_belt_common",
+	"from": "system",
+	"setting_id": "6nRHUtvJOUffocbu",
+	"instantiation": "true",
+	"printer_model": "Generic Belt Printer",
+	"nozzle_diameter": [
+		"0.4"
+	],
+	"printer_variant": "0.4",
+	"printable_area": [
+		"0x0",
+		"350x0",
+		"350x350",
+		"0x350"
+	],
+	"printable_height": "300"
+}

resources/profiles/Custom/machine/MyBeltPrinter 0.6 nozzle.json

@@ -0,0 +1,26 @@
+{
+	"type": "machine",
+	"name": "MyBeltPrinter 0.6 nozzle",
+	"inherits": "fdm_belt_common",
+	"from": "system",
+	"setting_id": "K0m9HbUNwKT4UCJV",
+	"instantiation": "true",
+	"printer_model": "Generic Belt Printer",
+	"nozzle_diameter": [
+		"0.6"
+	],
+	"max_layer_height": [
+		"0.4"
+	],
+	"min_layer_height": [
+		"0.12"
+	],
+	"printer_variant": "0.6",
+	"printable_area": [
+		"0x0",
+		"350x0",
+		"350x350",
+		"0x350"
+	],
+	"printable_height": "300"
+}

resources/profiles/Custom/machine/MyBeltPrinter 0.8 nozzle.json

@@ -0,0 +1,26 @@
+{
+	"type": "machine",
+	"name": "MyBeltPrinter 0.8 nozzle",
+	"inherits": "fdm_belt_common",
+	"from": "system",
+	"setting_id": "rHAweDz4eNwttPNA",
+	"instantiation": "true",
+	"printer_model": "Generic Belt Printer",
+	"nozzle_diameter": [
+		"0.8"
+	],
+	"max_layer_height": [
+		"0.6"
+	],
+	"min_layer_height": [
+		"0.2"
+	],
+	"printer_variant": "0.8",
+	"printable_area": [
+		"0x0",
+		"350x0",
+		"350x350",
+		"0x350"
+	],
+	"printable_height": "300"
+}

resources/profiles/Custom/machine/MyBeltPrinter.json

@@ -0,0 +1,12 @@
+{
+	"type": "machine_model",
+	"name": "Generic Belt Printer",
+	"model_id": "my_belt_01",
+	"nozzle_diameter": "0.4;0.2;0.6;0.8",
+	"machine_tech": "FFF",
+	"family": "MyPrinter",
+	"bed_model": "Custom_350_bed.stl",
+	"bed_texture": "orcaslicer_bed_texture.svg",
+	"hotend_model": "",
+	"default_materials": "Generic PLA @System;Generic PLA-CF @System;Generic PETG @System;Generic TPU @System;Generic PC @System;Generic PVA @System;Generic PA @System;Generic PA-CF @System"
+}

resources/profiles/Custom/machine/fdm_belt_common.json

@@ -0,0 +1,99 @@
+{
+	"type": "machine",
+	"name": "fdm_belt_common",
+	"inherits": "fdm_klipper_common",
+	"from": "system",
+	"instantiation": "false",
+	"gcode_flavor": "klipper",
+	"single_extruder_multi_material": "0",
+	"default_filament_profile": [
+		"Generic PLA @System"
+	],
+	"default_print_profile": "0.20mm Standard @MyBeltPrinter",
+	"max_layer_height": [
+		"0.32"
+	],
+	"min_layer_height": [
+		"0.08"
+	],
+	"deretraction_speed": [
+		"30"
+	],
+	"extruder_colour": [
+		"#FCE94F"
+	],
+	"extruder_offset": [
+		"0x0"
+	],
+	"long_retractions_when_cut": [
+		"0"
+	],
+	"nozzle_diameter": [
+		"0.4"
+	],
+	"retract_before_wipe": [
+		"70%"
+	],
+	"retract_length_toolchange": [
+		"2"
+	],
+	"retract_lift_above": [
+		"0"
+	],
+	"retract_lift_below": [
+		"0"
+	],
+	"retract_lift_enforce": [
+		"All Surfaces"
+	],
+	"retract_restart_extra": [
+		"0"
+	],
+	"retract_restart_extra_toolchange": [
+		"0"
+	],
+	"retract_when_changing_layer": [
+		"1"
+	],
+	"retraction_distances_when_cut": [
+		"18"
+	],
+	"retraction_length": [
+		"0.8"
+	],
+	"retraction_minimum_travel": [
+		"1"
+	],
+	"retraction_speed": [
+		"30"
+	],
+	"travel_slope": [
+		"3"
+	],
+	"wipe": [
+		"1"
+	],
+	"wipe_distance": [
+		"1"
+	],
+	"z_hop": [
+		"0.4"
+	],
+	"z_hop_types": [
+		"Normal Lift"
+	],
+	"gcode_remap_x": "rev_x",
+	"gcode_remap_y": "pos_z",
+	"gcode_remap_z": "pos_y",
+	"printer_extruder_id": [
+		"1"
+	],
+	"belt_printer": "1",
+	"belt_slice_rotation": "x",
+	"belt_slice_rotation_angle": "45",
+	"belt_slice_rotation_global": "1",
+	"build_plate_tilt_x": "45",
+	"purge_in_prime_tower": "0",
+	"scan_first_layer": "0",
+	"auxiliary_fan": "0"
+}

resources/profiles/Custom/process/0.12mm Fine @MyBeltPrinter.json

@@ -0,0 +1,20 @@
+{
+	"type": "process",
+	"name": "0.12mm Fine @MyBeltPrinter",
+	"inherits": "fdm_process_klipper_common",
+	"from": "system",
+	"setting_id": "EugqqdLJ423bgEwN",
+	"instantiation": "true",
+	"layer_height": "0.12",
+	"initial_layer_print_height": "0.12",
+	"bottom_shell_layers": "5",
+	"top_shell_layers": "6",
+	"support_top_z_distance": "0.08",
+	"support_bottom_z_distance": "0.08",
+	"skirt_loops": "0",
+	"skirt_distance": "0",
+	"compatible_printers": [
+		"MyBeltPrinter 0.2 nozzle",
+		"MyBeltPrinter 0.4 nozzle"
+	]
+}

resources/profiles/Custom/process/0.20mm Standard @MyBeltPrinter.json

@@ -0,0 +1,17 @@
+{
+	"type": "process",
+	"name": "0.20mm Standard @MyBeltPrinter",
+	"inherits": "fdm_process_klipper_common",
+	"from": "system",
+	"setting_id": "YzCDAgH3uLOM53pF",
+	"instantiation": "true",
+	"layer_height": "0.2",
+	"initial_layer_print_height": "0.2",
+	"skirt_loops": "0",
+	"skirt_distance": "0",
+	"compatible_printers": [
+		"MyBeltPrinter 0.4 nozzle",
+		"MyBeltPrinter 0.6 nozzle",
+		"MyBeltPrinter 0.8 nozzle"
+	]
+}

resources/profiles/IdeaFormer.json

@@ -0,0 +1,54 @@
+{
+    "name": "IdeaFormer",
+    "version": "02.00.00.03",
+    "force_update": "0",
+    "description": "IdeaFormer belt printer configurations",
+    "machine_model_list": [
+        {
+            "name": "IdeaFormer IR3 V2",
+            "sub_path": "machine/IdeaFormer IR3 V2.json"
+        }
+    ],
+    "process_list": [
+        {
+            "name": "fdm_process_common",
+            "sub_path": "process/fdm_process_common.json"
+        },
+        {
+            "name": "0.20mm Standard @IdeaFormer IR3 V2",
+            "sub_path": "process/0.20mm Standard @IdeaFormer IR3 V2.json"
+        }
+    ],
+    "filament_list": [
+        {
+            "name": "Generic PLA @IdeaFormer IR3 V2",
+            "sub_path": "filament/Generic PLA @IdeaFormer IR3 V2.json"
+        },
+        {
+            "name": "eSUN PLA @IdeaFormer IR3 V2",
+            "sub_path": "filament/eSUN PLA @IdeaFormer IR3 V2.json"
+        },
+        {
+            "name": "Generic PETG @IdeaFormer IR3 V2",
+            "sub_path": "filament/Generic PETG @IdeaFormer IR3 V2.json"
+        }
+    ],
+    "machine_list": [
+        {
+            "name": "fdm_machine_common",
+            "sub_path": "machine/fdm_machine_common.json"
+        },
+        {
+            "name": "fdm_klipper_common",
+            "sub_path": "machine/fdm_klipper_common.json"
+        },
+        {
+            "name": "fdm_belt_common",
+            "sub_path": "machine/fdm_belt_common.json"
+        },
+        {
+            "name": "IdeaFormer IR3 V2 0.4 nozzle",
+            "sub_path": "machine/IdeaFormer IR3 V2 0.4 nozzle.json"
+        }
+    ]
+}

resources/profiles/IdeaFormer/filament/Generic PETG @IdeaFormer IR3 V2.json

@@ -0,0 +1,113 @@
+{
+	"type": "filament",
+	"name": "Generic PETG @IdeaFormer IR3 V2",
+	"inherits": "Generic PETG @System",
+	"from": "system",
+	"setting_id": "n4zaXcUUzTqAxq5f",
+	"instantiation": "true",
+	"compatible_printers": [
+		"IdeaFormer IR3 V2 0.4 nozzle"
+	],
+	"filament_type": [
+		"PETG"
+	],
+	"filament_vendor": [
+		"Generic"
+	],
+	"filament_settings_id": [
+		"Generic PETG @IdeaFormer IR3 V2"
+	],
+	"filament_diameter": [
+		"1.75"
+	],
+	"filament_density": [
+		"1.27"
+	],
+	"filament_flow_ratio": [
+		"0.95"
+	],
+	"filament_cost": [
+		"25"
+	],
+	"filament_max_volumetric_speed": [
+		"10"
+	],
+	"nozzle_temperature": [
+		"240"
+	],
+	"nozzle_temperature_initial_layer": [
+		"245"
+	],
+	"nozzle_temperature_range_low": [
+		"220"
+	],
+	"nozzle_temperature_range_high": [
+		"260"
+	],
+	"temperature_vitrification": [
+		"70"
+	],
+	"hot_plate_temp": [
+		"80"
+	],
+	"hot_plate_temp_initial_layer": [
+		"80"
+	],
+	"cool_plate_temp": [
+		"80"
+	],
+	"cool_plate_temp_initial_layer": [
+		"80"
+	],
+	"textured_plate_temp": [
+		"80"
+	],
+	"textured_plate_temp_initial_layer": [
+		"80"
+	],
+	"fan_min_speed": [
+		"40"
+	],
+	"fan_max_speed": [
+		"60"
+	],
+	"overhang_fan_threshold": [
+		"25%"
+	],
+	"overhang_fan_speed": [
+		"80"
+	],
+	"close_fan_the_first_x_layers": [
+		"3"
+	],
+	"full_fan_speed_layer": [
+		"8"
+	],
+	"slow_down_min_speed": [
+		"20"
+	],
+	"slow_down_layer_time": [
+		"4"
+	],
+	"fan_cooling_layer_time": [
+		"100"
+	],
+	"reduce_fan_stop_start_freq": [
+		"1"
+	],
+	"filament_retraction_length": [
+		"2"
+	],
+	"filament_retraction_speed": [
+		"40"
+	],
+	"filament_deretraction_speed": [
+		"40"
+	],
+	"filament_z_hop": [
+		"0.4"
+	],
+	"filament_start_gcode": [
+		"; Generic PETG @IdeaFormer IR3 V2 — belt PETG, bed 80C"
+	]
+}

resources/profiles/IdeaFormer/filament/Generic PLA @IdeaFormer IR3 V2.json

@@ -0,0 +1,113 @@
+{
+	"type": "filament",
+	"name": "Generic PLA @IdeaFormer IR3 V2",
+	"inherits": "Generic PLA @System",
+	"from": "system",
+	"setting_id": "1xjycsEAFh6KQIhp",
+	"instantiation": "true",
+	"compatible_printers": [
+		"IdeaFormer IR3 V2 0.4 nozzle"
+	],
+	"filament_type": [
+		"PLA"
+	],
+	"filament_vendor": [
+		"Generic"
+	],
+	"filament_settings_id": [
+		"Generic PLA @IdeaFormer IR3 V2"
+	],
+	"filament_diameter": [
+		"1.75"
+	],
+	"filament_density": [
+		"1.24"
+	],
+	"filament_flow_ratio": [
+		"0.98"
+	],
+	"filament_cost": [
+		"20"
+	],
+	"filament_max_volumetric_speed": [
+		"12"
+	],
+	"nozzle_temperature": [
+		"215"
+	],
+	"nozzle_temperature_initial_layer": [
+		"220"
+	],
+	"nozzle_temperature_range_low": [
+		"190"
+	],
+	"nozzle_temperature_range_high": [
+		"240"
+	],
+	"temperature_vitrification": [
+		"45"
+	],
+	"hot_plate_temp": [
+		"75"
+	],
+	"hot_plate_temp_initial_layer": [
+		"75"
+	],
+	"cool_plate_temp": [
+		"75"
+	],
+	"cool_plate_temp_initial_layer": [
+		"75"
+	],
+	"textured_plate_temp": [
+		"75"
+	],
+	"textured_plate_temp_initial_layer": [
+		"75"
+	],
+	"fan_min_speed": [
+		"100"
+	],
+	"fan_max_speed": [
+		"100"
+	],
+	"overhang_fan_threshold": [
+		"50%"
+	],
+	"overhang_fan_speed": [
+		"100"
+	],
+	"close_fan_the_first_x_layers": [
+		"3"
+	],
+	"full_fan_speed_layer": [
+		"8"
+	],
+	"slow_down_min_speed": [
+		"20"
+	],
+	"slow_down_layer_time": [
+		"4"
+	],
+	"fan_cooling_layer_time": [
+		"100"
+	],
+	"reduce_fan_stop_start_freq": [
+		"1"
+	],
+	"filament_retraction_length": [
+		"1.5"
+	],
+	"filament_retraction_speed": [
+		"35"
+	],
+	"filament_deretraction_speed": [
+		"30"
+	],
+	"filament_z_hop": [
+		"0.4"
+	],
+	"filament_start_gcode": [
+		"; Generic PLA @IdeaFormer IR3 V2 — belt PLA, bed 75C"
+	]
+}

resources/profiles/IdeaFormer/filament/eSUN PLA @IdeaFormer IR3 V2.json

@@ -0,0 +1,36 @@
+{
+	"type": "filament",
+	"name": "eSUN PLA @IdeaFormer IR3 V2",
+	"inherits": "Generic PLA @IdeaFormer IR3 V2",
+	"filament_id": "OFkrxQC4",
+	"from": "system",
+	"setting_id": "XqkviBmFHEglXueX",
+	"instantiation": "true",
+	"compatible_printers": [
+		"IdeaFormer IR3 V2 0.4 nozzle"
+	],
+	"filament_type": [
+		"PLA"
+	],
+	"filament_vendor": [
+		"eSUN"
+	],
+	"filament_settings_id": [
+		"eSUN PLA @IdeaFormer IR3 V2"
+	],
+	"nozzle_temperature_initial_layer": [
+		"200"
+	],
+	"nozzle_temperature": [
+		"200"
+	],
+	"enable_pressure_advance": [
+		"1"
+	],
+	"pressure_advance": [
+		"0.12"
+	],
+	"filament_max_volumetric_speed": [
+		"20"
+	]
+}

resources/profiles/IdeaFormer/machine/IdeaFormer IR3 V2 0.4 nozzle.json

@@ -0,0 +1,94 @@
+{
+	"type": "machine",
+	"name": "IdeaFormer IR3 V2 0.4 nozzle",
+	"inherits": "fdm_belt_common",
+	"from": "system",
+	"setting_id": "MDQZgwRgg72lmjtu",
+	"instantiation": "true",
+	"printer_model": "IdeaFormer IR3 V2",
+	"printer_variant": "0.4",
+	"nozzle_diameter": [
+		"0.4"
+	],
+	"printable_area": [
+		"0x0",
+		"250x0",
+		"250x2000",
+		"0x2000"
+	],
+	"printable_height": "250",
+	"belt_printer_infinite_y": "1",
+	"thumbnails": [
+		"48x48/PNG",
+		"300x300/PNG"
+	],
+	"default_filament_profile": [
+		"Generic PLA @IdeaFormer IR3 V2"
+	],
+	"default_print_profile": "0.20mm Standard @IdeaFormer IR3 V2",
+	"use_relative_e_distances": "1",
+	"machine_max_acceleration_e": [
+		"5000"
+	],
+	"machine_max_acceleration_extruding": [
+		"5000"
+	],
+	"machine_max_acceleration_retracting": [
+		"1000"
+	],
+	"machine_max_acceleration_travel": [
+		"9000"
+	],
+	"machine_max_acceleration_x": [
+		"5000"
+	],
+	"machine_max_acceleration_y": [
+		"5000"
+	],
+	"machine_max_acceleration_z": [
+		"100"
+	],
+	"machine_max_jerk_e": [
+		"2.5"
+	],
+	"machine_max_jerk_x": [
+		"10"
+	],
+	"machine_max_jerk_y": [
+		"10"
+	],
+	"machine_max_jerk_z": [
+		"0.4"
+	],
+	"machine_max_speed_e": [
+		"60"
+	],
+	"machine_max_speed_x": [
+		"500"
+	],
+	"machine_max_speed_y": [
+		"500"
+	],
+	"machine_max_speed_z": [
+		"20"
+	],
+	"retraction_length": [
+		"2"
+	],
+	"retraction_speed": [
+		"40"
+	],
+	"deretraction_speed": [
+		"40"
+	],
+	"z_hop": [
+		"0.4"
+	],
+	"retract_lift_below": [
+		"300"
+	],
+	"machine_start_gcode": "; === IdeaFormer IR3 V2 Belt Printer Start ===\n; Axes: X=lateral, Y=gantry height (probe), Z=belt\nG90 ; absolute positioning\nM82 ; absolute extruder\nG21 ; millimeters\nG28 ; home all axes\nG1 Y20 F500 ; lift nozzle 20mm from belt\n; Bed + hotend temps come from the active filament profile. Belt PLA requires 75 C bed — use Generic/eSun PLA @IdeaFormer IR3 V2 filament presets to get it automatically.\nM140 S[hot_plate_temp_initial_layer] ; set bed temp\nM104 S[nozzle_temperature_initial_layer] ; hotend temp\nM109 S[nozzle_temperature_initial_layer] ; wait hotend\nM190 S[hot_plate_temp_initial_layer] ; wait bed\n; --- Purge blob ---\nG92 E0 ; zero extruder\nG1 Y.1 ; nozzle 0.1mm above belt\nG1 E15 F1000 ; purge 15mm blob\nG1 Z20 E25 F800 ; belt advance 20mm + extrude\nG1 E23 ; retract 2mm\nG28 Y ; re-probe belt surface\nG1 E25 ; de-retract\n; --- Prime lines (full 250mm bed width) ---\nFMS_on ; filament motion sensor\nG1 X250 E50 F2000 ; prime line 1\nG92 Z0 ; reset belt origin\nG1 Z.4 ; belt advance 0.4mm\nG1 X0 E75 ; prime line 2\nG1 F1000 ; default feedrate\nG92 E0 Z0 ; zero extruder + belt = print origin\n",
+	"machine_end_gcode": "; === IdeaFormer IR3 V2 Belt Printer End ===\nM400 ; wait for moves to finish\nM104 S0 ; heater off\nM140 S0 ; bed off\nG92 E0 ; zero extruder\nG1 E-5 F300 ; retract 5mm\nG4 P5000 ; wait for ooze\nG91 ; relative mode - keep every end move relative on a belt\nG1 Y20 F1000 ; raise gantry 20mm for clearance over the part\nG1 Z676 F3000 ; advance belt one full machine-depth to eject the part and clean the belt\nG90 ; back to absolute\nG28 X ; home X only - NEVER 'G28' all: that homes Z/belt and reverses the whole print back into the gantry\nFMS_off ; filament motion sensor off\nBED_MESH_CLEAR\nM84 ; disable motors\n",
+	"machine_pause_gcode": "PAUSE",
+	"layer_change_gcode": "G92 E0 ; belt: reset extruder at layer change (relative E)"
+}

resources/profiles/IdeaFormer/machine/IdeaFormer IR3 V2.json

@@ -0,0 +1,12 @@
+{
+	"type": "machine_model",
+	"name": "IdeaFormer IR3 V2",
+	"model_id": "IdeaFormer_IR3_V2",
+	"nozzle_diameter": "0.4",
+	"machine_tech": "FFF",
+	"family": "IdeaFormer",
+	"bed_model": "",
+	"bed_texture": "",
+	"hotend_model": "",
+	"default_materials": "Generic PLA @IdeaFormer IR3 V2;Generic PETG @IdeaFormer IR3 V2"
+}

resources/profiles/IdeaFormer/machine/fdm_belt_common.json

@@ -0,0 +1,99 @@
+{
+	"type": "machine",
+	"name": "fdm_belt_common",
+	"inherits": "fdm_klipper_common",
+	"from": "system",
+	"instantiation": "false",
+	"gcode_flavor": "klipper",
+	"single_extruder_multi_material": "0",
+	"default_filament_profile": [
+		"Generic PLA @System"
+	],
+	"default_print_profile": "0.20mm Standard @IdeaFormer IR3 V2",
+	"max_layer_height": [
+		"0.32"
+	],
+	"min_layer_height": [
+		"0.08"
+	],
+	"deretraction_speed": [
+		"30"
+	],
+	"extruder_colour": [
+		"#FCE94F"
+	],
+	"extruder_offset": [
+		"0x0"
+	],
+	"long_retractions_when_cut": [
+		"0"
+	],
+	"nozzle_diameter": [
+		"0.4"
+	],
+	"retract_before_wipe": [
+		"70%"
+	],
+	"retract_length_toolchange": [
+		"2"
+	],
+	"retract_lift_above": [
+		"0"
+	],
+	"retract_lift_below": [
+		"0"
+	],
+	"retract_lift_enforce": [
+		"All Surfaces"
+	],
+	"retract_restart_extra": [
+		"0"
+	],
+	"retract_restart_extra_toolchange": [
+		"0"
+	],
+	"retract_when_changing_layer": [
+		"1"
+	],
+	"retraction_distances_when_cut": [
+		"18"
+	],
+	"retraction_length": [
+		"0.8"
+	],
+	"retraction_minimum_travel": [
+		"1"
+	],
+	"retraction_speed": [
+		"30"
+	],
+	"travel_slope": [
+		"3"
+	],
+	"wipe": [
+		"1"
+	],
+	"wipe_distance": [
+		"1"
+	],
+	"z_hop": [
+		"0.4"
+	],
+	"z_hop_types": [
+		"Normal Lift"
+	],
+	"gcode_remap_x": "rev_x",
+	"gcode_remap_y": "pos_z",
+	"gcode_remap_z": "pos_y",
+	"printer_extruder_id": [
+		"1"
+	],
+	"belt_printer": "1",
+	"belt_slice_rotation": "x",
+	"belt_slice_rotation_angle": "45",
+	"belt_slice_rotation_global": "1",
+	"build_plate_tilt_x": "45",
+	"purge_in_prime_tower": "0",
+	"scan_first_layer": "0",
+	"auxiliary_fan": "0"
+}

resources/profiles/IdeaFormer/machine/fdm_klipper_common.json

@@ -0,0 +1,141 @@
+{
+	"type": "machine",
+	"name": "fdm_klipper_common",
+	"inherits": "fdm_machine_common",
+	"from": "system",
+	"instantiation": "false",
+	"gcode_flavor": "klipper",
+	"machine_max_acceleration_e": [
+		"5000",
+		"5000"
+	],
+	"machine_max_acceleration_extruding": [
+		"20000",
+		"20000"
+	],
+	"machine_max_acceleration_retracting": [
+		"5000",
+		"5000"
+	],
+	"machine_max_acceleration_travel": [
+		"20000",
+		"20000"
+	],
+	"machine_max_acceleration_x": [
+		"20000",
+		"20000"
+	],
+	"machine_max_acceleration_y": [
+		"20000",
+		"20000"
+	],
+	"machine_max_acceleration_z": [
+		"500",
+		"200"
+	],
+	"machine_max_speed_e": [
+		"25",
+		"25"
+	],
+	"machine_max_speed_x": [
+		"500",
+		"200"
+	],
+	"machine_max_speed_y": [
+		"500",
+		"200"
+	],
+	"machine_max_speed_z": [
+		"12",
+		"12"
+	],
+	"machine_max_jerk_e": [
+		"2.5",
+		"2.5"
+	],
+	"machine_max_jerk_x": [
+		"9",
+		"9"
+	],
+	"machine_max_jerk_y": [
+		"9",
+		"9"
+	],
+	"machine_max_jerk_z": [
+		"0.2",
+		"0.4"
+	],
+	"machine_min_extruding_rate": [
+		"0",
+		"0"
+	],
+	"machine_min_travel_rate": [
+		"0",
+		"0"
+	],
+	"max_layer_height": [
+		"0.32"
+	],
+	"min_layer_height": [
+		"0.08"
+	],
+	"printable_height": "250",
+	"extruder_clearance_radius": "65",
+	"extruder_clearance_height_to_rod": "36",
+	"extruder_clearance_height_to_lid": "140",
+	"printer_settings_id": "",
+	"printer_technology": "FFF",
+	"printer_variant": "0.4",
+	"retraction_minimum_travel": [
+		"1"
+	],
+	"retract_before_wipe": [
+		"70%"
+	],
+	"retract_when_changing_layer": [
+		"1"
+	],
+	"retraction_length": [
+		"0.8"
+	],
+	"retract_length_toolchange": [
+		"2"
+	],
+	"z_hop": [
+		"0.4"
+	],
+	"retract_restart_extra": [
+		"0"
+	],
+	"retract_restart_extra_toolchange": [
+		"0"
+	],
+	"retraction_speed": [
+		"30"
+	],
+	"deretraction_speed": [
+		"30"
+	],
+	"z_hop_types": "Normal Lift",
+	"silent_mode": "0",
+	"single_extruder_multi_material": "1",
+	"change_filament_gcode": "",
+	"wipe": [
+		"1"
+	],
+	"default_filament_profile": [
+		"Generic PLA @System"
+	],
+	"default_print_profile": "0.20mm Standard @MyKlipper",
+	"bed_exclude_area": [
+		"0x0"
+	],
+	"machine_start_gcode": "M190 S[bed_temperature_initial_layer_single]\nM109 S[nozzle_temperature_initial_layer]\nPRINT_START EXTRUDER=[nozzle_temperature_initial_layer] BED=[bed_temperature_initial_layer_single]\n",
+	"machine_end_gcode": "PRINT_END",
+	"layer_change_gcode": ";AFTER_LAYER_CHANGE\n;[layer_z]",
+	"before_layer_change_gcode": ";BEFORE_LAYER_CHANGE\n;[layer_z]\nG92 E0\n",
+	"machine_pause_gcode": "PAUSE",
+	"scan_first_layer": "0",
+	"nozzle_type": "undefine",
+	"auxiliary_fan": "0"
+}

resources/profiles/IdeaFormer/machine/fdm_machine_common.json

@@ -0,0 +1,119 @@
+{
+	"type": "machine",
+	"name": "fdm_machine_common",
+	"from": "system",
+	"instantiation": "false",
+	"printer_technology": "FFF",
+	"deretraction_speed": [
+		"40"
+	],
+	"extruder_colour": [
+		"#FCE94F"
+	],
+	"extruder_offset": [
+		"0x0"
+	],
+	"gcode_flavor": "marlin",
+	"silent_mode": "0",
+	"machine_max_acceleration_e": [
+		"5000"
+	],
+	"machine_max_acceleration_extruding": [
+		"10000"
+	],
+	"machine_max_acceleration_retracting": [
+		"1000"
+	],
+	"machine_max_acceleration_x": [
+		"10000"
+	],
+	"machine_max_acceleration_y": [
+		"10000"
+	],
+	"machine_max_acceleration_z": [
+		"500"
+	],
+	"machine_max_speed_e": [
+		"60"
+	],
+	"machine_max_speed_x": [
+		"500"
+	],
+	"machine_max_speed_y": [
+		"500"
+	],
+	"machine_max_speed_z": [
+		"10"
+	],
+	"machine_max_jerk_e": [
+		"5"
+	],
+	"machine_max_jerk_x": [
+		"8"
+	],
+	"machine_max_jerk_y": [
+		"8"
+	],
+	"machine_max_jerk_z": [
+		"0.4"
+	],
+	"machine_min_extruding_rate": [
+		"0"
+	],
+	"machine_min_travel_rate": [
+		"0"
+	],
+	"max_layer_height": [
+		"0.32"
+	],
+	"min_layer_height": [
+		"0.08"
+	],
+	"printable_height": "250",
+	"extruder_clearance_radius": "65",
+	"extruder_clearance_height_to_rod": "36",
+	"extruder_clearance_height_to_lid": "140",
+	"nozzle_diameter": [
+		"0.4"
+	],
+	"printer_settings_id": "",
+	"printer_variant": "0.4",
+	"retraction_minimum_travel": [
+		"2"
+	],
+	"retract_before_wipe": [
+		"70%"
+	],
+	"retract_when_changing_layer": [
+		"1"
+	],
+	"retraction_length": [
+		"1"
+	],
+	"retract_length_toolchange": [
+		"1"
+	],
+	"z_hop": [
+		"0"
+	],
+	"retract_restart_extra": [
+		"0"
+	],
+	"retract_restart_extra_toolchange": [
+		"0"
+	],
+	"retraction_speed": [
+		"60"
+	],
+	"single_extruder_multi_material": "1",
+	"change_filament_gcode": "",
+	"wipe": [
+		"1"
+	],
+	"default_print_profile": "",
+	"machine_start_gcode": "G0 Z20 F9000\nG92 E0; G1 E-10 F1200\nG28\nM970 Q1 A10 B10 C130 K0\nM970 Q1 A10 B131 C250 K1\nM974 Q1 S1 P0\nM970 Q0 A10 B10 C130 H20 K0\nM970 Q0 A10 B131 C250 K1\nM974 Q0 S1 P0\nM220 S100 ;Reset Feedrate\nM221 S100 ;Reset Flowrate\nG29 ;Home\nG90;\nG92 E0 ;Reset Extruder \nG1 Z2.0 F3000 ;Move Z Axis up \nG1 X10.1 Y20 Z0.28 F5000.0 ;Move to start position\nM109 S205;\nG1 X10.1 Y200.0 Z0.28 F1500.0 E15 ;Draw the first line\nG1 X10.4 Y200.0 Z0.28 F5000.0 ;Move to side a little\nG1 X10.4 Y20 Z0.28 F1500.0 E30 ;Draw the second line\nG92 E0 ;Reset Extruder \nG1 X110 Y110 Z2.0 F3000 ;Move Z Axis up",
+	"machine_end_gcode": "M400 ; wait for buffer to clear\nG92 E0 ; zero the extruder\nG1 E-4.0 F3600; retract \nG91\nG1 Z3;\nM104 S0 ; turn off hotend\nM140 S0 ; turn off bed\nM106 S0 ; turn off fan\nG90 \nG0 X110 Y200 F3600 \nprint_end",
+	"layer_change_gcode": ";AFTER_LAYER_CHANGE\n;[layer_z]",
+	"before_layer_change_gcode": ";BEFORE_LAYER_CHANGE\n;[layer_z]\nG92 E0\n",
+	"machine_pause_gcode": "M601"
+}

resources/profiles/IdeaFormer/process/0.20mm Standard @IdeaFormer IR3 V2.json

@@ -0,0 +1,23 @@
+{
+	"type": "process",
+	"name": "0.20mm Standard @IdeaFormer IR3 V2",
+	"inherits": "fdm_process_common",
+	"from": "system",
+	"setting_id": "91atcIwv5728phqX",
+	"instantiation": "true",
+	"layer_height": "0.2",
+	"initial_layer_print_height": "0.2",
+	"initial_layer_line_width": "0.42",
+	"wall_loops": "2",
+	"reduce_infill_retraction": "1",
+	"detect_overhang_wall": "1",
+	"skirt_loops": "0",
+	"skirt_distance": "0",
+	"sparse_infill_pattern": "grid",
+	"sparse_infill_speed": "200",
+	"support_base_pattern": "rectilinear",
+	"support_interface_pattern": "rectilinear",
+	"compatible_printers": [
+		"IdeaFormer IR3 V2 0.4 nozzle"
+	]
+}

resources/profiles/IdeaFormer/process/fdm_process_common.json

@@ -0,0 +1,108 @@
+{
+	"type": "process",
+	"name": "fdm_process_common",
+	"from": "system",
+	"instantiation": "false",
+	"adaptive_layer_height": "0",
+	"reduce_crossing_wall": "0",
+	"max_travel_detour_distance": "0",
+	"bottom_surface_pattern": "monotonic",
+	"bottom_shell_thickness": "0",
+	"bridge_speed": "50",
+	"brim_width": "5",
+	"brim_object_gap": "0.1",
+	"compatible_printers": [],
+	"compatible_printers_condition": "",
+	"print_sequence": "by layer",
+	"default_acceleration": "1000",
+	"initial_layer_acceleration": "500",
+	"top_surface_acceleration": "1000",
+	"travel_acceleration": "1000",
+	"inner_wall_acceleration": "1000",
+	"outer_wall_acceleration": "700",
+	"bridge_no_support": "0",
+	"draft_shield": "disabled",
+	"elefant_foot_compensation": "0",
+	"enable_arc_fitting": "0",
+	"wall_infill_order": "inner wall/outer wall/infill",
+	"infill_direction": "45",
+	"sparse_infill_density": "15%",
+	"sparse_infill_pattern": "crosshatch",
+	"initial_layer_print_height": "0.2",
+	"infill_combination": "0",
+	"infill_wall_overlap": "25%",
+	"interface_shells": "0",
+	"ironing_flow": "10%",
+	"ironing_spacing": "0.15",
+	"ironing_speed": "30",
+	"ironing_type": "no ironing",
+	"reduce_infill_retraction": "1",
+	"filename_format": "{input_filename_base}_{layer_height}mm_{filament_type[initial_tool]}_{printer_model}_{print_time}.gcode",
+	"detect_overhang_wall": "1",
+	"slowdown_for_curled_perimeters": "1",
+	"overhang_1_4_speed": "0",
+	"overhang_2_4_speed": "50",
+	"overhang_3_4_speed": "30",
+	"overhang_4_4_speed": "10",
+	"line_width": "110%",
+	"inner_wall_line_width": "110%",
+	"outer_wall_line_width": "100%",
+	"top_surface_line_width": "93.75%",
+	"sparse_infill_line_width": "110%",
+	"initial_layer_line_width": "120%",
+	"internal_solid_infill_line_width": "120%",
+	"support_line_width": "96%",
+	"wall_loops": "3",
+	"print_settings_id": "",
+	"raft_layers": "0",
+	"seam_position": "aligned",
+	"skirt_distance": "2",
+	"skirt_height": "3",
+	"min_skirt_length": "4",
+	"skirt_loops": "0",
+	"minimum_sparse_infill_area": "15",
+	"spiral_mode": "0",
+	"standby_temperature_delta": "-5",
+	"enable_support": "0",
+	"resolution": "0.012",
+	"support_type": "normal(auto)",
+	"support_on_build_plate_only": "0",
+	"support_top_z_distance": "0.2",
+	"support_bottom_z_distance": "0.2",
+	"support_filament": "0",
+	"support_interface_loop_pattern": "0",
+	"support_interface_filament": "0",
+	"support_interface_top_layers": "2",
+	"support_interface_bottom_layers": "2",
+	"support_interface_spacing": "0.5",
+	"support_interface_speed": "80",
+	"support_base_pattern": "default",
+	"support_base_pattern_spacing": "2.5",
+	"support_speed": "150",
+	"support_threshold_angle": "30",
+	"support_object_xy_distance": "0.35",
+	"tree_support_branch_angle": "30",
+	"tree_support_wall_count": "0",
+	"tree_support_with_infill": "0",
+	"detect_thin_wall": "0",
+	"top_surface_pattern": "monotonicline",
+	"top_shell_thickness": "0.8",
+	"enable_prime_tower": "1",
+	"wipe_tower_no_sparse_layers": "0",
+	"prime_tower_width": "60",
+	"xy_hole_compensation": "0",
+	"xy_contour_compensation": "0",
+	"layer_height": "0.2",
+	"bottom_shell_layers": "3",
+	"top_shell_layers": "4",
+	"bridge_flow": "1",
+	"initial_layer_speed": "45",
+	"initial_layer_infill_speed": "45",
+	"outer_wall_speed": "45",
+	"inner_wall_speed": "80",
+	"sparse_infill_speed": "150",
+	"internal_solid_infill_speed": "150",
+	"top_surface_speed": "50",
+	"gap_infill_speed": "30",
+	"travel_speed": "200"
+}

resources/profiles/Printcepts.json

@@ -0,0 +1,54 @@
+{
+	"name": "Printcepts",
+	"version": "01.00.00.01",
+	"force_update": "0",
+	"description": "Printcepts belt printer configurations",
+	"machine_model_list": [
+		{
+			"name": "BabyBelt Pro",
+			"sub_path": "machine/BabyBelt Pro.json"
+		}
+	],
+	"process_list": [
+		{
+			"name": "fdm_process_common",
+			"sub_path": "process/fdm_process_common.json"
+		},
+		{
+			"name": "0.20mm Standard @BabyBelt Pro",
+			"sub_path": "process/0.20mm Standard @BabyBelt Pro.json"
+		}
+	],
+	"filament_list": [
+		{
+			"name": "Generic PLA @BabyBelt Pro",
+			"sub_path": "filament/Generic PLA @BabyBelt Pro.json"
+		},
+		{
+			"name": "eSUN PLA @BabyBelt Pro",
+			"sub_path": "filament/eSUN PLA @BabyBelt Pro.json"
+		},
+		{
+			"name": "Generic PETG @BabyBelt Pro",
+			"sub_path": "filament/Generic PETG @BabyBelt Pro.json"
+		}
+	],
+	"machine_list": [
+		{
+			"name": "fdm_machine_common",
+			"sub_path": "machine/fdm_machine_common.json"
+		},
+		{
+			"name": "fdm_klipper_common",
+			"sub_path": "machine/fdm_klipper_common.json"
+		},
+		{
+			"name": "fdm_belt_common",
+			"sub_path": "machine/fdm_belt_common.json"
+		},
+		{
+			"name": "BabyBelt Pro 0.4 nozzle",
+			"sub_path": "machine/BabyBelt Pro 0.4 nozzle.json"
+		}
+	]
+}

resources/profiles/Printcepts/BabyBelt Pro_bed_texture.svg

@@ -0,0 +1,70 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="95.0mm" height="500.0mm" viewBox="0 0 95.0 500.0" preserveAspectRatio="xMidYMid meet">
+  <!-- Printcepts BabyBelt Pro bed texture: 95 x 500 mm belt plate. -->
+  <!-- Transparent plate; green (#195F30) BabyBelt Pro logo centered along X, near the bottom edge. -->
+  <rect x="0" y="0" width="95.0" height="500.0" fill="none"/>
+  <g transform="translate(14.2500,436.3488) scale(0.067538)">
+    <g transform="translate(-11.000000,692.938562) scale(0.100000,-0.100000)"
+fill="#195F30" stroke="none">
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+</svg>

resources/profiles/Printcepts/filament/Generic PETG @BabyBelt Pro.json

@@ -0,0 +1,113 @@
+{
+	"type": "filament",
+	"name": "Generic PETG @BabyBelt Pro",
+	"inherits": "Generic PETG @System",
+	"from": "system",
+	"setting_id": "gCzHpDNgVwQR6tgk",
+	"instantiation": "true",
+	"compatible_printers": [
+		"BabyBelt Pro 0.4 nozzle"
+	],
+	"filament_type": [
+		"PETG"
+	],
+	"filament_vendor": [
+		"Generic"
+	],
+	"filament_settings_id": [
+		"Generic PETG @BabyBelt Pro"
+	],
+	"filament_diameter": [
+		"1.75"
+	],
+	"filament_density": [
+		"1.27"
+	],
+	"filament_flow_ratio": [
+		"0.95"
+	],
+	"filament_cost": [
+		"25"
+	],
+	"filament_max_volumetric_speed": [
+		"10"
+	],
+	"nozzle_temperature": [
+		"240"
+	],
+	"nozzle_temperature_initial_layer": [
+		"245"
+	],
+	"nozzle_temperature_range_low": [
+		"220"
+	],
+	"nozzle_temperature_range_high": [
+		"260"
+	],
+	"temperature_vitrification": [
+		"70"
+	],
+	"hot_plate_temp": [
+		"80"
+	],
+	"hot_plate_temp_initial_layer": [
+		"80"
+	],
+	"cool_plate_temp": [
+		"80"
+	],
+	"cool_plate_temp_initial_layer": [
+		"80"
+	],
+	"textured_plate_temp": [
+		"80"
+	],
+	"textured_plate_temp_initial_layer": [
+		"80"
+	],
+	"fan_min_speed": [
+		"40"
+	],
+	"fan_max_speed": [
+		"60"
+	],
+	"overhang_fan_threshold": [
+		"25%"
+	],
+	"overhang_fan_speed": [
+		"80"
+	],
+	"close_fan_the_first_x_layers": [
+		"3"
+	],
+	"full_fan_speed_layer": [
+		"8"
+	],
+	"slow_down_min_speed": [
+		"20"
+	],
+	"slow_down_layer_time": [
+		"4"
+	],
+	"fan_cooling_layer_time": [
+		"100"
+	],
+	"reduce_fan_stop_start_freq": [
+		"1"
+	],
+	"filament_retraction_length": [
+		"2"
+	],
+	"filament_retraction_speed": [
+		"40"
+	],
+	"filament_deretraction_speed": [
+		"40"
+	],
+	"filament_z_hop": [
+		"0.4"
+	],
+	"filament_start_gcode": [
+		"; Generic PETG @BabyBelt Pro — belt PETG, bed 80C"
+	]
+}

resources/profiles/Printcepts/filament/Generic PLA @BabyBelt Pro.json

@@ -0,0 +1,113 @@
+{
+	"type": "filament",
+	"name": "Generic PLA @BabyBelt Pro",
+	"inherits": "Generic PLA @System",
+	"from": "system",
+	"setting_id": "24PpcnhVx9v5f4fD",
+	"instantiation": "true",
+	"compatible_printers": [
+		"BabyBelt Pro 0.4 nozzle"
+	],
+	"filament_type": [
+		"PLA"
+	],
+	"filament_vendor": [
+		"Generic"
+	],
+	"filament_settings_id": [
+		"Generic PLA @BabyBelt Pro"
+	],
+	"filament_diameter": [
+		"1.75"
+	],
+	"filament_density": [
+		"1.24"
+	],
+	"filament_flow_ratio": [
+		"0.98"
+	],
+	"filament_cost": [
+		"20"
+	],
+	"filament_max_volumetric_speed": [
+		"12"
+	],
+	"nozzle_temperature": [
+		"215"
+	],
+	"nozzle_temperature_initial_layer": [
+		"220"
+	],
+	"nozzle_temperature_range_low": [
+		"190"
+	],
+	"nozzle_temperature_range_high": [
+		"240"
+	],
+	"temperature_vitrification": [
+		"45"
+	],
+	"hot_plate_temp": [
+		"75"
+	],
+	"hot_plate_temp_initial_layer": [
+		"75"
+	],
+	"cool_plate_temp": [
+		"75"
+	],
+	"cool_plate_temp_initial_layer": [
+		"75"
+	],
+	"textured_plate_temp": [
+		"75"
+	],
+	"textured_plate_temp_initial_layer": [
+		"75"
+	],
+	"fan_min_speed": [
+		"100"
+	],
+	"fan_max_speed": [
+		"100"
+	],
+	"overhang_fan_threshold": [
+		"50%"
+	],
+	"overhang_fan_speed": [
+		"100"
+	],
+	"close_fan_the_first_x_layers": [
+		"3"
+	],
+	"full_fan_speed_layer": [
+		"8"
+	],
+	"slow_down_min_speed": [
+		"20"
+	],
+	"slow_down_layer_time": [
+		"4"
+	],
+	"fan_cooling_layer_time": [
+		"100"
+	],
+	"reduce_fan_stop_start_freq": [
+		"1"
+	],
+	"filament_retraction_length": [
+		"1.5"
+	],
+	"filament_retraction_speed": [
+		"35"
+	],
+	"filament_deretraction_speed": [
+		"30"
+	],
+	"filament_z_hop": [
+		"0.4"
+	],
+	"filament_start_gcode": [
+		"; Generic PLA @BabyBelt Pro — belt PLA, bed 75C"
+	]
+}

resources/profiles/Printcepts/filament/eSUN PLA @BabyBelt Pro.json

@@ -0,0 +1,36 @@
+{
+	"type": "filament",
+	"name": "eSUN PLA @BabyBelt Pro",
+	"inherits": "Generic PLA @BabyBelt Pro",
+	"filament_id": "OFkrxQC4",
+	"from": "system",
+	"setting_id": "EH3X7oE0DU5tSpjW",
+	"instantiation": "true",
+	"compatible_printers": [
+		"BabyBelt Pro 0.4 nozzle"
+	],
+	"filament_type": [
+		"PLA"
+	],
+	"filament_vendor": [
+		"eSUN"
+	],
+	"filament_settings_id": [
+		"eSUN PLA @BabyBelt Pro"
+	],
+	"nozzle_temperature_initial_layer": [
+		"200"
+	],
+	"nozzle_temperature": [
+		"200"
+	],
+	"enable_pressure_advance": [
+		"1"
+	],
+	"pressure_advance": [
+		"0.12"
+	],
+	"filament_max_volumetric_speed": [
+		"20"
+	]
+}

resources/profiles/Printcepts/machine/BabyBelt Pro 0.4 nozzle.json

@@ -0,0 +1,87 @@
+{
+	"type": "machine",
+	"name": "BabyBelt Pro 0.4 nozzle",
+	"inherits": "fdm_belt_common",
+	"from": "system",
+	"setting_id": "34OWINlJpJgA9DwQ",
+	"instantiation": "true",
+	"printer_model": "BabyBelt Pro",
+	"printer_variant": "0.4",
+	"nozzle_diameter": [
+		"0.4"
+	],
+	"default_filament_profile": [
+		"Generic PLA @BabyBelt Pro"
+	],
+	"default_print_profile": "0.20mm Standard @BabyBelt Pro",
+	"printable_area": [
+		"0x0",
+		"95x0",
+		"95x500",
+		"0x500"
+	],
+	"printable_height": "100",
+	"best_object_pos": "0.5,0.05",
+	"nozzle_type": [
+		"hardened_steel"
+	],
+	"printer_extruder_id": [
+		"1"
+	],
+	"printer_extruder_variant": [
+		"Direct Drive Standard"
+	],
+	"thumbnails": [
+		"48x48/PNG",
+		"300x300/PNG"
+	],
+	"machine_max_acceleration_e": [
+		"500",
+		"5000"
+	],
+	"machine_max_acceleration_extruding": [
+		"500",
+		"20000"
+	],
+	"machine_max_acceleration_retracting": [
+		"500",
+		"5000"
+	],
+	"machine_max_acceleration_x": [
+		"500",
+		"20000"
+	],
+	"machine_max_acceleration_y": [
+		"500",
+		"20000"
+	],
+	"machine_max_junction_deviation": [
+		"0.01"
+	],
+	"machine_max_speed_x": [
+		"50",
+		"200"
+	],
+	"machine_max_speed_y": [
+		"50",
+		"200"
+	],
+	"machine_max_speed_z": [
+		"5",
+		"12"
+	],
+	"retraction_length": [
+		"1.5"
+	],
+	"retraction_speed": [
+		"20"
+	],
+	"deretraction_speed": [
+		"25"
+	],
+	"retract_lift_enforce": [
+		"Top and Bottom"
+	],
+	"support_chamber_temp_control": "0",
+	"machine_start_gcode": ";Start GCode\nPRINT_START ANGLE=[belt_slice_rotation_angle] EXTRUDER=[nozzle_temperature_initial_layer] BED=[hot_plate_temp_initial_layer] MATERIAL=[filament_type]\n"
+}

resources/profiles/Printcepts/machine/BabyBelt Pro.json

@@ -0,0 +1,12 @@
+{
+	"type": "machine_model",
+	"name": "BabyBelt Pro",
+	"model_id": "Printcepts_BabyBelt_Pro",
+	"nozzle_diameter": "0.4",
+	"machine_tech": "FFF",
+	"family": "Printcepts",
+	"bed_model": "",
+	"bed_texture": "BabyBelt Pro_bed_texture.svg",
+	"hotend_model": "",
+	"default_materials": "Generic PLA @BabyBelt Pro;Generic PETG @BabyBelt Pro"
+}

resources/profiles/Printcepts/machine/fdm_belt_common.json

@@ -0,0 +1,99 @@
+{
+	"type": "machine",
+	"name": "fdm_belt_common",
+	"inherits": "fdm_klipper_common",
+	"from": "system",
+	"instantiation": "false",
+	"gcode_flavor": "klipper",
+	"single_extruder_multi_material": "0",
+	"default_filament_profile": [
+		"Generic PLA @System"
+	],
+	"default_print_profile": "0.20mm Standard @BabyBelt Pro",
+	"max_layer_height": [
+		"0.32"
+	],
+	"min_layer_height": [
+		"0.08"
+	],
+	"deretraction_speed": [
+		"30"
+	],
+	"extruder_colour": [
+		"#FCE94F"
+	],
+	"extruder_offset": [
+		"0x0"
+	],
+	"long_retractions_when_cut": [
+		"0"
+	],
+	"nozzle_diameter": [
+		"0.4"
+	],
+	"retract_before_wipe": [
+		"70%"
+	],
+	"retract_length_toolchange": [
+		"2"
+	],
+	"retract_lift_above": [
+		"0"
+	],
+	"retract_lift_below": [
+		"0"
+	],
+	"retract_lift_enforce": [
+		"All Surfaces"
+	],
+	"retract_restart_extra": [
+		"0"
+	],
+	"retract_restart_extra_toolchange": [
+		"0"
+	],
+	"retract_when_changing_layer": [
+		"1"
+	],
+	"retraction_distances_when_cut": [
+		"18"
+	],
+	"retraction_length": [
+		"0.8"
+	],
+	"retraction_minimum_travel": [
+		"1"
+	],
+	"retraction_speed": [
+		"30"
+	],
+	"travel_slope": [
+		"3"
+	],
+	"wipe": [
+		"1"
+	],
+	"wipe_distance": [
+		"1"
+	],
+	"z_hop": [
+		"0.4"
+	],
+	"z_hop_types": [
+		"Normal Lift"
+	],
+	"gcode_remap_x": "rev_x",
+	"gcode_remap_y": "pos_z",
+	"gcode_remap_z": "pos_y",
+	"printer_extruder_id": [
+		"1"
+	],
+	"belt_printer": "1",
+	"belt_slice_rotation": "x",
+	"belt_slice_rotation_angle": "45",
+	"belt_slice_rotation_global": "1",
+	"build_plate_tilt_x": "45",
+	"purge_in_prime_tower": "0",
+	"scan_first_layer": "0",
+	"auxiliary_fan": "0"
+}

resources/profiles/Printcepts/machine/fdm_klipper_common.json

@@ -0,0 +1,141 @@
+{
+	"type": "machine",
+	"name": "fdm_klipper_common",
+	"inherits": "fdm_machine_common",
+	"from": "system",
+	"instantiation": "false",
+	"gcode_flavor": "klipper",
+	"machine_max_acceleration_e": [
+		"5000",
+		"5000"
+	],
+	"machine_max_acceleration_extruding": [
+		"20000",
+		"20000"
+	],
+	"machine_max_acceleration_retracting": [
+		"5000",
+		"5000"
+	],
+	"machine_max_acceleration_travel": [
+		"20000",
+		"20000"
+	],
+	"machine_max_acceleration_x": [
+		"20000",
+		"20000"
+	],
+	"machine_max_acceleration_y": [
+		"20000",
+		"20000"
+	],
+	"machine_max_acceleration_z": [
+		"500",
+		"200"
+	],
+	"machine_max_speed_e": [
+		"25",
+		"25"
+	],
+	"machine_max_speed_x": [
+		"500",
+		"200"
+	],
+	"machine_max_speed_y": [
+		"500",
+		"200"
+	],
+	"machine_max_speed_z": [
+		"12",
+		"12"
+	],
+	"machine_max_jerk_e": [
+		"2.5",
+		"2.5"
+	],
+	"machine_max_jerk_x": [
+		"9",
+		"9"
+	],
+	"machine_max_jerk_y": [
+		"9",
+		"9"
+	],
+	"machine_max_jerk_z": [
+		"0.2",
+		"0.4"
+	],
+	"machine_min_extruding_rate": [
+		"0",
+		"0"
+	],
+	"machine_min_travel_rate": [
+		"0",
+		"0"
+	],
+	"max_layer_height": [
+		"0.32"
+	],
+	"min_layer_height": [
+		"0.08"
+	],
+	"printable_height": "250",
+	"extruder_clearance_radius": "65",
+	"extruder_clearance_height_to_rod": "36",
+	"extruder_clearance_height_to_lid": "140",
+	"printer_settings_id": "",
+	"printer_technology": "FFF",
+	"printer_variant": "0.4",
+	"retraction_minimum_travel": [
+		"1"
+	],
+	"retract_before_wipe": [
+		"70%"
+	],
+	"retract_when_changing_layer": [
+		"1"
+	],
+	"retraction_length": [
+		"0.8"
+	],
+	"retract_length_toolchange": [
+		"2"
+	],
+	"z_hop": [
+		"0.4"
+	],
+	"retract_restart_extra": [
+		"0"
+	],
+	"retract_restart_extra_toolchange": [
+		"0"
+	],
+	"retraction_speed": [
+		"30"
+	],
+	"deretraction_speed": [
+		"30"
+	],
+	"z_hop_types": "Normal Lift",
+	"silent_mode": "0",
+	"single_extruder_multi_material": "1",
+	"change_filament_gcode": "",
+	"wipe": [
+		"1"
+	],
+	"default_filament_profile": [
+		"Generic PLA @System"
+	],
+	"default_print_profile": "0.20mm Standard @MyKlipper",
+	"bed_exclude_area": [
+		"0x0"
+	],
+	"machine_start_gcode": "M190 S[bed_temperature_initial_layer_single]\nM109 S[nozzle_temperature_initial_layer]\nPRINT_START EXTRUDER=[nozzle_temperature_initial_layer] BED=[bed_temperature_initial_layer_single]\n",
+	"machine_end_gcode": "PRINT_END",
+	"layer_change_gcode": ";AFTER_LAYER_CHANGE\n;[layer_z]",
+	"before_layer_change_gcode": ";BEFORE_LAYER_CHANGE\n;[layer_z]\nG92 E0\n",
+	"machine_pause_gcode": "PAUSE",
+	"scan_first_layer": "0",
+	"nozzle_type": "undefine",
+	"auxiliary_fan": "0"
+}

resources/profiles/Printcepts/machine/fdm_machine_common.json

@@ -0,0 +1,119 @@
+{
+	"type": "machine",
+	"name": "fdm_machine_common",
+	"from": "system",
+	"instantiation": "false",
+	"printer_technology": "FFF",
+	"deretraction_speed": [
+		"40"
+	],
+	"extruder_colour": [
+		"#FCE94F"
+	],
+	"extruder_offset": [
+		"0x0"
+	],
+	"gcode_flavor": "marlin",
+	"silent_mode": "0",
+	"machine_max_acceleration_e": [
+		"5000"
+	],
+	"machine_max_acceleration_extruding": [
+		"10000"
+	],
+	"machine_max_acceleration_retracting": [
+		"1000"
+	],
+	"machine_max_acceleration_x": [
+		"10000"
+	],
+	"machine_max_acceleration_y": [
+		"10000"
+	],
+	"machine_max_acceleration_z": [
+		"500"
+	],
+	"machine_max_speed_e": [
+		"60"
+	],
+	"machine_max_speed_x": [
+		"500"
+	],
+	"machine_max_speed_y": [
+		"500"
+	],
+	"machine_max_speed_z": [
+		"10"
+	],
+	"machine_max_jerk_e": [
+		"5"
+	],
+	"machine_max_jerk_x": [
+		"8"
+	],
+	"machine_max_jerk_y": [
+		"8"
+	],
+	"machine_max_jerk_z": [
+		"0.4"
+	],
+	"machine_min_extruding_rate": [
+		"0"
+	],
+	"machine_min_travel_rate": [
+		"0"
+	],
+	"max_layer_height": [
+		"0.32"
+	],
+	"min_layer_height": [
+		"0.08"
+	],
+	"printable_height": "250",
+	"extruder_clearance_radius": "65",
+	"extruder_clearance_height_to_rod": "36",
+	"extruder_clearance_height_to_lid": "140",
+	"nozzle_diameter": [
+		"0.4"
+	],
+	"printer_settings_id": "",
+	"printer_variant": "0.4",
+	"retraction_minimum_travel": [
+		"2"
+	],
+	"retract_before_wipe": [
+		"70%"
+	],
+	"retract_when_changing_layer": [
+		"1"
+	],
+	"retraction_length": [
+		"1"
+	],
+	"retract_length_toolchange": [
+		"1"
+	],
+	"z_hop": [
+		"0"
+	],
+	"retract_restart_extra": [
+		"0"
+	],
+	"retract_restart_extra_toolchange": [
+		"0"
+	],
+	"retraction_speed": [
+		"60"
+	],
+	"single_extruder_multi_material": "1",
+	"change_filament_gcode": "",
+	"wipe": [
+		"1"
+	],
+	"default_print_profile": "",
+	"machine_start_gcode": "G0 Z20 F9000\nG92 E0; G1 E-10 F1200\nG28\nM970 Q1 A10 B10 C130 K0\nM970 Q1 A10 B131 C250 K1\nM974 Q1 S1 P0\nM970 Q0 A10 B10 C130 H20 K0\nM970 Q0 A10 B131 C250 K1\nM974 Q0 S1 P0\nM220 S100 ;Reset Feedrate\nM221 S100 ;Reset Flowrate\nG29 ;Home\nG90;\nG92 E0 ;Reset Extruder \nG1 Z2.0 F3000 ;Move Z Axis up \nG1 X10.1 Y20 Z0.28 F5000.0 ;Move to start position\nM109 S205;\nG1 X10.1 Y200.0 Z0.28 F1500.0 E15 ;Draw the first line\nG1 X10.4 Y200.0 Z0.28 F5000.0 ;Move to side a little\nG1 X10.4 Y20 Z0.28 F1500.0 E30 ;Draw the second line\nG92 E0 ;Reset Extruder \nG1 X110 Y110 Z2.0 F3000 ;Move Z Axis up",
+	"machine_end_gcode": "M400 ; wait for buffer to clear\nG92 E0 ; zero the extruder\nG1 E-4.0 F3600; retract \nG91\nG1 Z3;\nM104 S0 ; turn off hotend\nM140 S0 ; turn off bed\nM106 S0 ; turn off fan\nG90 \nG0 X110 Y200 F3600 \nprint_end",
+	"layer_change_gcode": ";AFTER_LAYER_CHANGE\n;[layer_z]",
+	"before_layer_change_gcode": ";BEFORE_LAYER_CHANGE\n;[layer_z]\nG92 E0\n",
+	"machine_pause_gcode": "M601"
+}

resources/profiles/Printcepts/process/0.20mm Standard @BabyBelt Pro.json

@@ -0,0 +1,23 @@
+{
+	"type": "process",
+	"name": "0.20mm Standard @BabyBelt Pro",
+	"inherits": "fdm_process_common",
+	"from": "system",
+	"setting_id": "JGfGtqX6CWjCt437",
+	"instantiation": "true",
+	"layer_height": "0.2",
+	"initial_layer_print_height": "0.2",
+	"initial_layer_line_width": "0.42",
+	"wall_loops": "2",
+	"reduce_infill_retraction": "1",
+	"detect_overhang_wall": "1",
+	"skirt_loops": "0",
+	"skirt_distance": "0",
+	"sparse_infill_pattern": "grid",
+	"sparse_infill_speed": "200",
+	"support_base_pattern": "rectilinear",
+	"support_interface_pattern": "rectilinear",
+	"compatible_printers": [
+		"BabyBelt Pro 0.4 nozzle"
+	]
+}

resources/profiles/Printcepts/process/fdm_process_common.json

@@ -0,0 +1,108 @@
+{
+	"type": "process",
+	"name": "fdm_process_common",
+	"from": "system",
+	"instantiation": "false",
+	"adaptive_layer_height": "0",
+	"reduce_crossing_wall": "0",
+	"max_travel_detour_distance": "0",
+	"bottom_surface_pattern": "monotonic",
+	"bottom_shell_thickness": "0",
+	"bridge_speed": "50",
+	"brim_width": "5",
+	"brim_object_gap": "0.1",
+	"compatible_printers": [],
+	"compatible_printers_condition": "",
+	"print_sequence": "by layer",
+	"default_acceleration": "1000",
+	"initial_layer_acceleration": "500",
+	"top_surface_acceleration": "1000",
+	"travel_acceleration": "1000",
+	"inner_wall_acceleration": "1000",
+	"outer_wall_acceleration": "700",
+	"bridge_no_support": "0",
+	"draft_shield": "disabled",
+	"elefant_foot_compensation": "0",
+	"enable_arc_fitting": "0",
+	"wall_infill_order": "inner wall/outer wall/infill",
+	"infill_direction": "45",
+	"sparse_infill_density": "15%",
+	"sparse_infill_pattern": "crosshatch",
+	"initial_layer_print_height": "0.2",
+	"infill_combination": "0",
+	"infill_wall_overlap": "25%",
+	"interface_shells": "0",
+	"ironing_flow": "10%",
+	"ironing_spacing": "0.15",
+	"ironing_speed": "30",
+	"ironing_type": "no ironing",
+	"reduce_infill_retraction": "1",
+	"filename_format": "{input_filename_base}_{layer_height}mm_{filament_type[initial_tool]}_{printer_model}_{print_time}.gcode",
+	"detect_overhang_wall": "1",
+	"slowdown_for_curled_perimeters": "1",
+	"overhang_1_4_speed": "0",
+	"overhang_2_4_speed": "50",
+	"overhang_3_4_speed": "30",
+	"overhang_4_4_speed": "10",
+	"line_width": "110%",
+	"inner_wall_line_width": "110%",
+	"outer_wall_line_width": "100%",
+	"top_surface_line_width": "93.75%",
+	"sparse_infill_line_width": "110%",
+	"initial_layer_line_width": "120%",
+	"internal_solid_infill_line_width": "120%",
+	"support_line_width": "96%",
+	"wall_loops": "3",
+	"print_settings_id": "",
+	"raft_layers": "0",
+	"seam_position": "aligned",
+	"skirt_distance": "2",
+	"skirt_height": "3",
+	"min_skirt_length": "4",
+	"skirt_loops": "0",
+	"minimum_sparse_infill_area": "15",
+	"spiral_mode": "0",
+	"standby_temperature_delta": "-5",
+	"enable_support": "0",
+	"resolution": "0.012",
+	"support_type": "normal(auto)",
+	"support_on_build_plate_only": "0",
+	"support_top_z_distance": "0.2",
+	"support_bottom_z_distance": "0.2",
+	"support_filament": "0",
+	"support_interface_loop_pattern": "0",
+	"support_interface_filament": "0",
+	"support_interface_top_layers": "2",
+	"support_interface_bottom_layers": "2",
+	"support_interface_spacing": "0.5",
+	"support_interface_speed": "80",
+	"support_base_pattern": "default",
+	"support_base_pattern_spacing": "2.5",
+	"support_speed": "150",
+	"support_threshold_angle": "30",
+	"support_object_xy_distance": "0.35",
+	"tree_support_branch_angle": "30",
+	"tree_support_wall_count": "0",
+	"tree_support_with_infill": "0",
+	"detect_thin_wall": "0",
+	"top_surface_pattern": "monotonicline",
+	"top_shell_thickness": "0.8",
+	"enable_prime_tower": "1",
+	"wipe_tower_no_sparse_layers": "0",
+	"prime_tower_width": "60",
+	"xy_hole_compensation": "0",
+	"xy_contour_compensation": "0",
+	"layer_height": "0.2",
+	"bottom_shell_layers": "3",
+	"top_shell_layers": "4",
+	"bridge_flow": "1",
+	"initial_layer_speed": "45",
+	"initial_layer_infill_speed": "45",
+	"outer_wall_speed": "45",
+	"inner_wall_speed": "80",
+	"sparse_infill_speed": "150",
+	"internal_solid_infill_speed": "150",
+	"top_surface_speed": "50",
+	"gap_infill_speed": "30",
+	"travel_speed": "200"
+}

resources/shaders/110/gouraud.fs

@@ -26,6 +26,7 @@ struct SlopeDetection
     bool actived;
 	float normal_z;
     mat3 volume_world_normal_matrix;
+    vec3 up_direction;
 };
 
 uniform vec4 uniform_color;

resources/shaders/110/gouraud.vs

@@ -23,6 +23,7 @@ struct SlopeDetection
     bool actived;
 	float normal_z;
     mat3 volume_world_normal_matrix;
+    vec3 up_direction;
 };
 
 uniform mat4 view_model_matrix;
@@ -73,8 +74,8 @@ void main()
     // Point in homogenous coordinates.
     world_pos = volume_world_matrix * vec4(v_position, 1.0);
 
-    // z component of normal vector in world coordinate used for slope shading
+    // dot product of world normal with up direction, used for slope shading
-    world_normal_z = slope.actived ? (normalize(slope.volume_world_normal_matrix * v_normal)).z : 0.0;
+    world_normal_z = slope.actived ? dot(normalize(slope.volume_world_normal_matrix * v_normal), slope.up_direction) : 0.0;
 
     gl_Position = projection_matrix * position;
     if (is_outline) {

resources/shaders/110/mm_gouraud.fs

@@ -37,6 +37,7 @@ struct SlopeDetection
     bool actived;
 	 float normal_z;
     mat3 volume_world_normal_matrix;
+    vec3 up_direction;
 };
 uniform SlopeDetection slope;
 
@@ -85,7 +86,7 @@ void main()
               color = LightBlue;
               alpha = 1.0;
          }
-         else if( transformed_normal.z < slope.normal_z - EPSILON)
+         else if( dot(transformed_normal, slope.up_direction) < slope.normal_z - EPSILON)
         {
             color = color * 0.5 + LightRed * 0.5;
             alpha = 1.0;

resources/shaders/110/mm_gouraud.vs

@@ -24,6 +24,7 @@ struct SlopeDetection
     bool actived;
 	float normal_z;
     mat3 volume_world_normal_matrix;
+    vec3 up_direction;
 };
 uniform SlopeDetection slope;
 void main()

resources/shaders/140/gouraud.fs

@@ -29,6 +29,7 @@ struct SlopeDetection
     bool actived;
 	float normal_z;
     mat3 volume_world_normal_matrix;
+    vec3 up_direction;
 };
 
 uniform vec4 uniform_color;

resources/shaders/140/gouraud.vs

@@ -23,6 +23,7 @@ struct SlopeDetection
     bool actived;
 	float normal_z;
     mat3 volume_world_normal_matrix;
+    vec3 up_direction;
 };
 
 uniform mat4 view_model_matrix;
@@ -73,8 +74,8 @@ void main()
     // Point in homogenous coordinates.
     world_pos = volume_world_matrix * vec4(v_position, 1.0);
 
-    // z component of normal vector in world coordinate used for slope shading
+    // dot product of world normal with up direction, used for slope shading
-    world_normal_z = slope.actived ? (normalize(slope.volume_world_normal_matrix * v_normal)).z : 0.0;
+    world_normal_z = slope.actived ? dot(normalize(slope.volume_world_normal_matrix * v_normal), slope.up_direction) : 0.0;
 
     gl_Position = projection_matrix * position;
     if (is_outline) {

resources/shaders/140/mm_gouraud.fs

@@ -37,6 +37,7 @@ struct SlopeDetection
     bool actived;
 	 float normal_z;
     mat3 volume_world_normal_matrix;
+    vec3 up_direction;
 };
 uniform SlopeDetection slope;
 
@@ -87,7 +88,7 @@ void main()
               color = LightBlue;
               alpha = 1.0;
          }
-         else if( transformed_normal.z < slope.normal_z - EPSILON)
+         else if( dot(transformed_normal, slope.up_direction) < slope.normal_z - EPSILON)
         {
             color = color * 0.5 + LightRed * 0.5;
             alpha = 1.0;

resources/shaders/140/mm_gouraud.vs

@@ -24,6 +24,7 @@ struct SlopeDetection
     bool actived;
 	float normal_z;
     mat3 volume_world_normal_matrix;
+    vec3 up_direction;
 };
 uniform SlopeDetection slope;
 void main()

scripts/filament_id_snapshot.json

@@ -1549,6 +1549,7 @@
     "Flashforge/Generic PLA",
     "FlyingBear/Generic PLA",
     "Ginger Additive/Generic PLA",
+    "IdeaFormer/Generic PLA",
     "InfiMech/Generic PLA",
     "LONGER/Generic PLA",
     "Lulzbot/Generic PLA",
@@ -1556,6 +1557,7 @@
     "OrcaFilamentLibrary/Generic PLA",
     "Peopoly/Generic PLA",
     "Phrozen/Generic PLA",
+    "Printcepts/Generic PLA",
     "Prusa/Generic PLA",
     "Qidi/Generic PLA",
     "RH3D/Generic PLA",
@@ -4298,12 +4300,14 @@
     "Flashforge/Generic PETG",
     "FlyingBear/Generic PETG",
     "Ginger Additive/Generic PETG",
+    "IdeaFormer/Generic PETG",
     "InfiMech/Generic PETG",
     "LONGER/Generic PETG",
     "Lulzbot/Generic PETG",
     "OrcaArena/Generic PETG",
     "OrcaFilamentLibrary/Generic PETG",
     "Peopoly/Generic PETG",
+    "Printcepts/Generic PETG",
     "Prusa/Generic PETG",
     "Qidi/Generic PETG",
     "RH3D/Generic PETG",
@@ -5886,6 +5890,15 @@
    "filament_type": "PA-GF",
    "filament_vendor": "Eryone"
   },
+  "OFkrxQC4": {
+   "filaments": [
+    "IdeaFormer/eSUN PLA",
+    "Printcepts/eSUN PLA"
+   ],
+   "name": "eSUN PLA",
+   "filament_type": "PLA",
+   "filament_vendor": "eSUN"
+  },
   "OFks6esg": {
    "filaments": [
     "Creality/EN-PLA+"

src/CMakeLists.txt

@@ -91,6 +91,12 @@ if (SLIC3R_GUI)
 #    list(REMOVE_ITEM wxWidgets_LIBRARIES oleacc)
 
     find_package(wxInspector REQUIRED)
+    # wxInspector 1.0.0 installs its headers but accidentally declares the
+    # INSTALL_INTERFACE include directory PRIVATE, so its imported target does
+    # not expose them to consumers. Restore the package prefix include path until
+    # the upstream export is fixed.
+    get_filename_component(WXINSPECTOR_PREFIX "${wxInspector_DIR}/../../.." ABSOLUTE)
+    target_include_directories(wxInspector::wxInspector INTERFACE "${WXINSPECTOR_PREFIX}/include")
 
     # wxInspector's exported interface names the release wxWidgets import
     # libraries, which a Debug build cannot link. wx is linked above instead.
@@ -186,7 +192,7 @@ endif ()
 # Add the Slic3r GUI library, libcurl, OpenGL and GLU libraries.
 if (SLIC3R_GUI)
 #    target_link_libraries(OrcaSlicer ws2_32 uxtheme setupapi libslic3r_gui ${wxWidgets_LIBRARIES})
-target_link_libraries(OrcaSlicer libslic3r_gui)
+target_link_libraries(OrcaSlicer libslic3r_gui wxInspector::wxInspector)
     if (MSVC)
         # Generate debug symbols even in release mode.
         target_link_options(OrcaSlicer PUBLIC "$<$<CONFIG:RELEASE>:/DEBUG>")

src/libslic3r/BeltBrim.cpp

@@ -0,0 +1,516 @@
+#include "BeltBrim.hpp"
+
+#include "ClipperUtils.hpp"
+#include "Flow.hpp"
+#include "Layer.hpp"
+#include "Polygon.hpp"
+#include "Print.hpp"
+#include "ShortestPath.hpp"
+#include "Support/BeltFloorContext.hpp"
+
+#include <algorithm>
+
+namespace Slic3r {
+
+// ---------------------------------------------------------------- scaling
+
+static inline Point scale_u_point(const Point &p, int from_axis, double factor)
+{
+    // llround, not a cast: casting truncates toward zero, so a round trip would
+    // walk every vertex toward the origin by up to one unit per pass.
+    return from_axis == 0 ?
+        Point(coord_t(std::llround(double(p.x()) * factor)), p.y()) :
+        Point(p.x(), coord_t(std::llround(double(p.y()) * factor)));
+}
+
+static inline void scale_u_polygon(Polygon &poly, int from_axis, double factor)
+{
+    for (Point &p : poly.points)
+        p = scale_u_point(p, from_axis, factor);
+}
+
+ExPolygons belt_scale_u(const ExPolygons &src, const BeltBrimFrame &frame, double factor)
+{
+    ExPolygons out = src;
+    for (ExPolygon &ex : out) {
+        scale_u_polygon(ex.contour, frame.from_axis, factor);
+        for (Polygon &hole : ex.holes)
+            scale_u_polygon(hole, frame.from_axis, factor);
+    }
+    return out;
+}
+
+Polylines belt_scale_u(const Polylines &src, const BeltBrimFrame &frame, double factor)
+{
+    Polylines out = src;
+    for (Polyline &pl : out)
+        for (Point &p : pl.points)
+            p = scale_u_point(p, frame.from_axis, factor);
+    return out;
+}
+
+// ---------------------------------------------------------------- sweep
+
+ExPolygons sweep_ex(const ExPolygons &src, const Point &t)
+{
+    if (src.empty())
+        return {};
+    if (t == Point(0, 0))
+        return src;
+
+    // One parallelogram per boundary edge.  Together with P and P + t these
+    // cover the Minkowski sum exactly: for any q = p + s*t with p in P and
+    // s in [0, 1], let s* be the smallest lambda >= 0 with q - lambda*t in P.
+    // Either s* == 0 (so q is in P) or q - s* * t lies on some boundary edge e,
+    // putting q in that edge's parallelogram.  Hole edges must be included, or
+    // holes narrower than t along t would wrongly survive the sweep.
+    Polygons quads;
+    for (const ExPolygon &ex : src)
+        for (size_t c = 0; c < ex.num_contours(); ++ c)
+            for (const Line &e : ex.contour_or_hole(c).lines()) {
+                if (e.a == e.b)
+                    continue;
+                Polygon q;
+                q.points = { e.a, e.b, e.b + t, e.a + t };
+                // The non-zero fill rule counts a clockwise ring as -1, which
+                // would punch a hole instead of adding material.  Edges parallel
+                // to t give a zero-area quad; Clipper discards those harmlessly.
+                if (q.is_clockwise())
+                    q.reverse();
+                quads.emplace_back(std::move(q));
+            }
+
+    ExPolygons shifted = src;
+    for (ExPolygon &ex : shifted)
+        ex.translate(t);
+
+    // union_ex(ExPolygons, Polygons) uses pftNonZero, which is the fill rule the
+    // argument above relies on.
+    return union_ex(union_ex(src, shifted), quads);
+}
+
+// ---------------------------------------------------------------- brim region
+
+ExPolygons belt_brim_region(const ExPolygons    &footprint_flat,
+                            bool                 has_outer,
+                            bool                 has_inner,
+                            coord_t              brim_width,
+                            coord_t              object_gap,
+                            coord_t              leading,
+                            coord_t              lateral,
+                            const BeltBrimFrame &frame)
+{
+    if (footprint_flat.empty() || (! has_outer && ! has_inner))
+        return {};
+
+    ExPolygons out;
+
+    if (has_outer) {
+        // Offset the outer ring from the contours only, so a hole cannot punch
+        // through it.  Same reasoning as the plate brim in Brim.cpp.
+        Polygons contours;
+        contours.reserve(footprint_flat.size());
+        for (const ExPolygon &ex : footprint_flat)
+            contours.emplace_back(ex.contour);
+
+        // Inner and outer boundary offset from the same polygon, to avoid
+        // round-off mismatch between them.
+        ExPolygons inner = offset_ex(contours, float(object_gap), jtRound, SCALED_RESOLUTION);
+
+        // Close the interior before offsetting outwards.  A belt contact patch is often a
+        // narrow, broken-up strip, and the offset rings of two islands less than
+        // 2 x brim_width apart merge and fill the space between them - space that lies
+        // UNDER the part, which is not what "outer brim" means.  Closing also swallows
+        // holes in the patch for the same reason.  Concavity-filling only, so an apron or
+        // any other outward protrusion is untouched.
+        ExPolygons envelope = brim_width > 0 ? closing_ex(inner, float(brim_width)) : inner;
+
+        ExPolygons base  = envelope;
+        if (leading > 0) {
+            // Sweep downhill from the gapped keep-out, so the apron is contiguous with
+            // the ring instead of starting inside the gap.
+            const Point t = frame.from_axis == 0 ?
+                Point(frame.downhill_sign() * leading, 0) :
+                Point(0, frame.downhill_sign() * leading);
+            base = union_ex(base, sweep_ex(envelope, t));
+        }
+        if (lateral > 0) {
+            // Across the belt, both ways.  Swept from `base` so the apron is widened
+            // too, and in the flattened frame the cross-belt axis is unscaled, so this
+            // distance is already a true on-belt distance.
+            const Point t = frame.from_axis == 0 ? Point(0, lateral) : Point(lateral, 0);
+            ExPolygons widened = union_ex(sweep_ex(base, t), sweep_ex(base, Point(-t.x(), -t.y())));
+            base = union_ex(base, to_polygons(widened));
+        }
+        ExPolygons outer = offset_ex(base, float(brim_width), jtRound, SCALED_RESOLUTION);
+        expolygons_append(out, diff_ex(outer, envelope));
+    }
+
+    if (has_inner) {
+        // Holes reversed so a negative offset grows inward, mirroring Brim.cpp.
+        // No apron here: an apron growing into a hole interior is never useful.
+        Polygons holes;
+        for (const ExPolygon &ex : footprint_flat)
+            polygons_append(holes, ex.holes);
+        polygons_reverse(holes);
+        if (! holes.empty()) {
+            ExPolygons hole_inner = offset_ex(holes, - float(brim_width + object_gap));
+            ExPolygons hole_outer = offset_ex(holes, - float(object_gap));
+            expolygons_append(out, intersection_ex(diff_ex(hole_outer, hole_inner), holes));
+        }
+    }
+
+    return union_ex(out);
+}
+
+// ---------------------------------------------------------------- line lattice
+
+std::vector<coord_t> belt_brim_line_positions(coord_t u_lo,
+                                              coord_t u_hi,
+                                              coord_t pitch_u,
+                                              coord_t u_anchor)
+{
+    std::vector<coord_t> out;
+    if (pitch_u <= 0 || u_hi <= u_lo)
+        return out;
+
+    // Walk the lattice from just below u_lo.  Integer arithmetic throughout, so
+    // the half-open interval needs no epsilon: a point landing exactly on u_hi
+    // belongs to the next band.
+    int64_t k = int64_t(std::floor(double(u_lo - u_anchor) / double(pitch_u))) - 1;
+    while (u_anchor + coord_t(k) * pitch_u < u_lo)
+        ++ k;
+    for (;; ++ k) {
+        const coord_t u = u_anchor + coord_t(k) * pitch_u;
+        if (u >= u_hi)
+            break;
+        out.emplace_back(u);
+    }
+    return out;
+}
+
+// ---------------------------------------------------------------- pipeline
+
+// A band of the belt surface as an explicit box, clamped to `bounds` along the
+// shear axis.  Deliberately not BeltFloorContext::surface_polygon(): those
+// half-planes span +-1000 mm, which is wasteful to clip against and dangerous to
+// feed through the flattening scale.
+static Polygon band_box(const BoundingBox &bounds, int from_axis, coordf_t u_lo, coordf_t u_hi)
+{
+    coord_t lo = scale_(u_lo);
+    coord_t hi = scale_(u_hi);
+    const coord_t bmin = from_axis == 0 ? bounds.min.x() : bounds.min.y();
+    const coord_t bmax = from_axis == 0 ? bounds.max.x() : bounds.max.y();
+    lo = std::max(lo, bmin);
+    hi = std::min(hi, bmax);
+    Polygon poly;
+    if (hi <= lo)
+        return poly;
+    if (from_axis == 0)
+        poly.points = { Point(lo, bounds.min.y()), Point(hi, bounds.min.y()),
+                        Point(hi, bounds.max.y()), Point(lo, bounds.max.y()) };
+    else
+        poly.points = { Point(bounds.min.x(), lo), Point(bounds.max.x(), lo),
+                        Point(bounds.max.x(), hi), Point(bounds.min.x(), hi) };
+    return poly;
+}
+
+// Everything the per-band line generator needs, gathered once per object.
+struct BeltBrimContext
+{
+    BeltFloorContext ctx;
+    BeltBrimFrame    frame;
+    ExPolygons       region;      // brim region, object-local slicing XY
+    BoundingBox      region_bbox;
+    Flow             brim_flow;
+    coord_t          pitch_u   = 0;
+    coord_t          u_anchor  = 0;
+    double           in_plane_pitch = 0.;   // mm
+};
+
+// Emit the cross-belt brim lines that belong to the band [print_z - height, print_z].
+static void belt_brim_band_paths(const BeltBrimContext      &bc,
+                                 coordf_t                    print_z,
+                                 coordf_t                    height,
+                                 const Polygons             &obstacles,
+                                 ExtrusionEntityCollection  &out,
+                                 ExPolygons                 &areas_out)
+{
+    coordf_t u_lo = bc.ctx.cutoff_u(print_z - height);
+    coordf_t u_hi = bc.ctx.cutoff_u(print_z);
+    if (u_lo > u_hi)
+        std::swap(u_lo, u_hi);
+
+    // How wide this band is measured ON the belt, versus one nominal bead.
+    const double band_in_plane = (u_hi - u_lo) * bc.frame.u_stretch();
+
+    // Fraction of the layer height at which a line sits above the belt.  Toward the
+    // downhill edge, so the sheet is reasonably thick while the nozzle stays clear of
+    // the belt itself.
+    static constexpr double BAND_CLEARANCE_FRACTION = 0.75;
+
+    std::vector<coord_t> us;
+    double uniform_clearance = 0.;   // 0 => derive per line from its own position
+    double line_pitch        = bc.in_plane_pitch;
+    if (band_in_plane <= bc.in_plane_pitch + EPSILON) {
+        // Steep belt, which is the normal case: the band is narrower than one bead, so
+        // exactly one line fits.  Place it at a FIXED fraction of the band rather than
+        // on a nominal-spacing lattice.  On a lattice each line lands at an arbitrary
+        // point in its band, the clearance sweeps [0, height] from band to band, and the
+        // bead width therefore varies by 2x - visible as ragged, uneven brim lines.
+        // Anchoring to the band makes the clearance identical everywhere, so every bead
+        // is the same width.
+        //
+        // The spacing is then whatever the bands give (height / sin(tilt) on the belt)
+        // rather than the nominal bead spacing, so the flow below is matched to THAT
+        // pitch.  Matched flow at the real pitch is what keeps the sheet uniform and
+        // gap-free; using nominal flow at band spacing would over-feed it.
+        us.push_back(scale_(bc.ctx.cutoff_u(print_z - BAND_CLEARANCE_FRACTION * height)));
+        uniform_clearance = BAND_CLEARANCE_FRACTION * height;
+        line_pitch        = band_in_plane;
+    } else {
+        // Shallow belt: the band is wider than a bead, so it takes several lines and they
+        // have to sit on the nominal lattice.  Their clearances then differ, and so do
+        // their widths - unavoidable here, but shallow belts are the rare case.
+        us = belt_brim_line_positions(scale_(u_lo), scale_(u_hi), bc.pitch_u, bc.u_anchor);
+    }
+    if (us.empty())
+        return;
+
+    const Polygons region_polys = to_polygons(bc.region);
+
+    // One lattice line at a time: the clearance - and therefore the extrusion
+    // volume - is a property of the line's u, so the pieces of different lines
+    // must not be pooled before the flow is resolved.
+    // Overshoot the region so the clip, not the line's ends, decides the extent.
+    const coord_t margin = coord_t(SCALED_EPSILON) + 1;
+    for (const coord_t u : us) {
+        Polyline line;
+        if (bc.frame.from_axis == 0)
+            line.points = { Point(u, coord_t(bc.region_bbox.min.y() - margin)),
+                            Point(u, coord_t(bc.region_bbox.max.y() + margin)) };
+        else
+            line.points = { Point(coord_t(bc.region_bbox.min.x() - margin), u),
+                            Point(coord_t(bc.region_bbox.max.x() + margin), u) };
+
+        Polylines pieces = intersection_pl(Polylines{ line }, region_polys);
+        if (! obstacles.empty())
+            pieces = diff_pl(pieces, obstacles);
+        if (pieces.empty())
+            continue;
+
+        // Nozzle-to-belt clearance for this line.  Constant along the line, because the
+        // belt height depends only on the shear-axis coordinate.  Band-anchored lines
+        // share one clearance by construction; lattice lines (shallow belts) each get
+        // their own, clamped so neither end of a band yields an unprintable bead.
+        double clearance = uniform_clearance;
+        if (clearance <= 0.) {
+            const Point probe = bc.frame.from_axis == 0 ? Point(u, 0) : Point(0, u);
+            clearance = print_z - bc.ctx.floor_print_z(probe);
+            clearance = std::min(std::max(clearance, 0.5 * height), height);
+        }
+
+        // with_cross_section, not with_height: it reaches the prescribed volume while
+        // KEEPING the extrusion spacing, so the bead is sized to fill exactly one
+        // pitch x clearance cell of the sheet.
+        const Flow f = bc.brim_flow.with_cross_section(float(line_pitch * clearance));
+
+        // Footprint of these beads, for the first-layer convex hull and bbox.
+        for (const Polygon &p : offset(pieces, 0.5f * float(f.scaled_width())))
+            areas_out.emplace_back(ExPolygon(p));
+
+        extrusion_entities_append_paths(out.entities, chain_polylines(std::move(pieces)),
+                                        erBrim, f.mm3_per_mm(), f.width(), float(clearance));
+    }
+}
+
+// Union of everything extruded at `print_z` that the brim must keep clear of, expressed
+// in `self`'s local slicing frame.  Includes `self` itself: its slice at this Z can
+// overhang outside the belt footprint and land in the brim ring, which the flattened
+// brim_object_gap - a belt-plane separation - does not cover.
+//
+// THREADING: this runs inside posSupportMaterial, which Print::process() executes for all
+// objects in a tbb::parallel_for (Print.cpp).  Object slices are finished by then and safe
+// to read across objects, but SUPPORT layers are not: another object's thread may be
+// inside clear_support_layers() - which deletes the SupportLayer pointers - right now, so
+// touching a foreign object's support_layers() here is a use-after-free.  Only this
+// object's own supports are consulted; they are complete, because make_belt_brim() runs at
+// the tail of this object's own generate_support_material().  The cost is that the brim
+// does not dodge a *different* object's support at the same Z, which needs the objects to
+// overlap in the belt direction in the first place.
+// `region_bbox` bounds the brim; anything outside it cannot clip a brim line, so whole
+// objects are skipped without materialising their polygons.  On a typical plate the
+// objects do not overlap and every foreign object drops out here, which matters because
+// this runs once per band - hundreds of times per object.
+static Polygons belt_brim_obstacles(const Print &print, const PrintObject &self,
+                                    const BoundingBox &region_bbox, coordf_t print_z, coordf_t tol)
+{
+    const Point shift_self = self.instances().empty() ? Point(0, 0)
+                                                      : self.instances().front().shift_without_plate_offset();
+    Polygons out;
+    for (const PrintObject *o : print.objects()) {
+        const bool is_self = (o == &self);
+        for (const PrintInstance &inst : o->instances()) {
+            const Point delta = inst.shift_without_plate_offset() - shift_self;
+            if (const Layer *l = o->get_layer_at_printz(print_z, tol)) {
+                BoundingBox lb = get_extents(l->lslices);
+                lb.translate(delta.x(), delta.y());
+                if (lb.overlap(region_bbox)) {
+                    Polygons ps = to_polygons(l->lslices);
+                    for (Polygon &p : ps)
+                        p.translate(delta);
+                    polygons_append(out, std::move(ps));
+                }
+            }
+            if (! is_self)
+                continue;
+            if (const SupportLayer *sl = o->get_support_layer_at_printz(print_z, tol)) {
+                Polygons ps = sl->support_fills.polygons_covered_by_spacing();
+                for (Polygon &p : ps)
+                    p.translate(delta);
+                polygons_append(out, std::move(ps));
+            }
+        }
+    }
+    if (out.size() < 2)
+        return out;   // union_() of 0 or 1 polygons is pure overhead
+    return union_(out);
+}
+
+void make_belt_brim(PrintObject &object)
+{
+    object.clear_belt_brim();
+    if (! object.has_belt_brim())
+        return;
+
+    const Print &print = *object.print();
+    BeltBrimContext bc;
+    if (! bc.ctx.init(object.slicing_parameters(), print.config()))
+        return;
+    bc.frame = BeltBrimFrame{ bc.ctx.shear_factor(), bc.ctx.from_axis() };
+
+    const size_t nlayers = object.layers().size();
+    if (nlayers == 0)
+        return;
+
+    // 1. Belt footprint: the union of each layer's slice clipped to that layer's
+    //    own contact band.  This is the object's bottom face, which on a belt is
+    //    spread over every layer instead of sitting in layer 0.
+    ExPolygons footprint_acc;
+    for (size_t i = 0; i < nlayers; ++ i) {
+        const Layer &layer = *object.layers()[i];
+        if (layer.lslices.empty())
+            continue;
+        // print_z - height, not the previous layer's print_z: variable layer
+        // heights make the latter wrong.
+        coordf_t u_lo = bc.ctx.cutoff_u(layer.print_z - layer.height);
+        coordf_t u_hi = bc.ctx.cutoff_u(layer.print_z);
+        if (u_lo > u_hi)
+            std::swap(u_lo, u_hi);
+        BoundingBox bb = get_extents(layer.lslices);
+        bb.offset(scale_(1.));
+        const Polygon band = band_box(bb, bc.frame.from_axis, u_lo, u_hi);
+        if (band.empty())
+            continue;
+        expolygons_append(footprint_acc, intersection_ex(layer.lslices, Polygons{ band }));
+    }
+    const ExPolygons footprint = union_ex(footprint_acc);
+    if (footprint.empty())
+        return;
+
+    // 2. Brim region, offset in the flattened (true on-belt) metric.
+    const PrintObjectConfig &cfg = object.config();
+    bc.brim_flow = print.brim_flow();
+    const double  flow_w = bc.brim_flow.scaled_spacing() * SCALING_FACTOR;
+    // Quantize to an even number of lines, as the plate brim does.
+    const coord_t width   = scale_(std::floor(cfg.brim_width.value / flow_w / 2) * flow_w * 2);
+    const coord_t leading = scale_(cfg.leading_brim_length.value);
+    const coord_t lateral = scale_(cfg.extra_brim_width.value);
+    const coord_t gap     = scale_(cfg.brim_object_gap.value);
+
+    // Belt printers collapse Auto / Mouse ear / Painted to outer-only: the auto width
+    // heuristic and flat ear discs have no meaning on a tilted plane.  Leading-edge-only
+    // is an outer brim too; it is narrowed down to the first contact below.
+    const BrimType bt = cfg.brim_type.value;
+    const bool has_outer = bt == btOuterOnly || bt == btOuterAndInner
+                        || bt == btAutoBrim  || bt == btEar || bt == btPainted
+                        || bt == btLeadingEdgeOnly;
+    const bool has_inner = bt == btInnerOnly || bt == btOuterAndInner;
+
+    bc.region = belt_unflatten(
+        belt_brim_region(belt_flatten(footprint, bc.frame), has_outer, has_inner,
+                         width, gap, leading, lateral, bc.frame),
+        bc.frame);
+
+    if (bt == btLeadingEdgeOnly && ! bc.region.empty()) {
+        // Keep only what lies at or downhill of the object's FIRST contact with the
+        // belt, so the part is supported as it lands and nothing is printed alongside
+        // it afterwards.  The cut is the uphill edge of the first layer's contact band:
+        // everything past it belongs to later contacts.
+        const coordf_t u_cut   = bc.ctx.cutoff_u(object.layers().front()->print_z);
+        BoundingBox    keep_bb = get_extents(bc.region);
+        keep_bb.offset(scale_(1.));
+        const bool     low_side = bc.frame.shear > 0.;   // downhill is -u
+        const Polygon  keep = band_box(keep_bb, bc.frame.from_axis,
+            low_side ? unscale<double>(bc.frame.from_axis == 0 ? keep_bb.min.x() : keep_bb.min.y()) : u_cut,
+            low_side ? u_cut : unscale<double>(bc.frame.from_axis == 0 ? keep_bb.max.x() : keep_bb.max.y()));
+        bc.region = keep.empty() ? ExPolygons{} : intersection_ex(bc.region, Polygons{ keep });
+    }
+
+    if (bc.region.empty())
+        return;
+    bc.region_bbox = get_extents(bc.region);
+
+    // 3. Line lattice.  Fixed pitch in the flattened metric, anchored at the
+    //    footprint's leading-most edge so lines stay collinear across
+    //    disconnected islands and across the apron prologue.
+    bc.pitch_u = std::max<coord_t>(1, coord_t(bc.brim_flow.scaled_spacing() * bc.frame.cos_tilt()));
+    bc.in_plane_pitch = unscale<double>(bc.pitch_u) * bc.frame.u_stretch();
+    {
+        const BoundingBox fbb = get_extents(footprint);
+        const bool low_side = bc.frame.shear > 0.;
+        bc.u_anchor = bc.frame.from_axis == 0 ? (low_side ? fbb.min.x() : fbb.max.x())
+                                              : (low_side ? fbb.min.y() : fbb.max.y());
+    }
+
+    // 4. Bands coincident with an object layer.
+    std::vector<ExtrusionEntityCollection> by_layer(nlayers);
+    std::vector<ExPolygons>                areas_by_layer(nlayers);
+    for (size_t i = 0; i < nlayers; ++ i) {
+        const Layer &layer = *object.layers()[i];
+        const Polygons obstacles = belt_brim_obstacles(print, object, bc.region_bbox, layer.print_z, 0.5 * layer.height);
+        belt_brim_band_paths(bc, layer.print_z, layer.height, obstacles, by_layer[i], areas_by_layer[i]);
+    }
+
+    // 5. Apron prologue: the part of the region downhill of the object's first
+    //    layer, which has no object layer to ride on.
+    std::vector<BeltBrimBand> prologue;
+    {
+        const Layer   &first  = *object.layers().front();
+        const coordf_t h      = first.height;
+        const bool     low_side = bc.frame.shear > 0.;
+        const coord_t  u_lead_s = bc.frame.from_axis == 0
+            ? (low_side ? bc.region_bbox.min.x() : bc.region_bbox.max.x())
+            : (low_side ? bc.region_bbox.min.y() : bc.region_bbox.max.y());
+        const coordf_t u_lead  = unscale<double>(u_lead_s);
+        // print_z at which the belt surface crosses the region's leading edge.
+        const coordf_t z_lead  = bc.ctx.shear_factor() * u_lead
+                               + bc.ctx.floor_offset() + bc.ctx.z_shift();
+        if (h > EPSILON)
+            for (coordf_t z = first.print_z - h; z > z_lead - h; z -= h) {
+                const Polygons obstacles = belt_brim_obstacles(print, object, bc.region_bbox, z, 0.5 * h);
+                BeltBrimBand band;
+                band.print_z = z;
+                band.height  = h;
+                belt_brim_band_paths(bc, z, h, obstacles, band.fills, band.areas);
+                if (! band.fills.empty())
+                    prologue.emplace_back(std::move(band));
+            }
+        // Lowest Z first, so collect_layers_to_print sees them in print order.
+        std::reverse(prologue.begin(), prologue.end());
+    }
+
+    object.set_belt_brim(std::move(by_layer), std::move(areas_by_layer), std::move(prologue));
+}
+
+} // namespace Slic3r

src/libslic3r/BeltBrim.hpp

@@ -0,0 +1,169 @@
+#ifndef slic3r_BeltBrim_hpp_
+#define slic3r_BeltBrim_hpp_
+
+#include "ExPolygon.hpp"
+#include "ExtrusionEntityCollection.hpp"
+#include "Point.hpp"
+#include "Polyline.hpp"
+
+#include <cmath>
+#include <vector>
+
+// Belt-printer brim geometry.
+//
+// A belt printer slices in a ROTATED frame, so the belt surface is not the
+// Z=0 bed plane but a tilted plane in slicing space:
+//
+//     z_slicing(u) = shear * u + floor_offset + z_shift,   u = X or Y
+//
+// where `shear == tan(tilt)` (SlicingParameters::belt_floor_shear_factor) and
+// the axis is selected by SlicingParameters::belt_floor_from_axis.  See
+// Support/BeltFloorContext.hpp for the canonical accessors.
+//
+// Consequences that drive everything in this file:
+//
+//   * A horizontal slicing layer touches the belt only along a narrow strip at
+//     its leading edge, `layer_height / shear` wide (~0.2 mm at 45 degrees).
+//     The object's belt footprint - its bottom face - is therefore spread over
+//     every layer, not contained in layer 0.
+//   * Distances measured in slicing XY are NOT on-belt distances: moving `du`
+//     along the shear axis travels `du / cos(tilt)` across the belt.  So brim
+//     offsets have to be taken in a "flattened" space where the shear axis is
+//     stretched by `1 / cos(tilt)`, then mapped back.
+//   * Brim ahead of the part (downhill) lies at slicing Z BELOW the object's
+//     first layer, because the object's layer 0 is precisely its leading
+//     contact with the belt.
+//
+// Everything here is pure geometry on ExPolygons/Polylines so it can be unit
+// tested without a Print.  Keep user-visible strings out of this file: it is
+// not listed in localization/i18n/list.txt.
+
+namespace Slic3r {
+
+// Tilt window within which the BELT plane, not the bed plane, is the adhesion
+// surface.  Below ~1 degree a belt is a flat bed as far as adhesion goes, and the
+// contact band would be layer_height/sin(tilt) - tens of millimetres - so the
+// ordinary plate brim is both correct and cheaper.  Above ~85 degrees the whole
+// brim compresses into a sliver and is not worth generating.
+inline constexpr double BELT_BRIM_MIN_TILT_DEG = 1.;
+inline constexpr double BELT_BRIM_MAX_TILT_DEG = 85.;
+
+// Description of the tilted belt plane, reduced to what the brim geometry needs.
+struct BeltBrimFrame
+{
+    // tan(tilt).  Sign selects which way is downhill.
+    double shear     = 0.;
+    // 0 = X, 1 = Y.  Matches BeltFloorContext::from_axis().
+    int    from_axis = 1;
+
+    // 1 / cos(tilt).  Stretch factor that turns a projected distance along
+    // `from_axis` into the true distance travelled across the belt.
+    double u_stretch() const { return std::sqrt(1. + shear * shear); }
+    // cos(tilt).  The inverse mapping.
+    double cos_tilt()  const { return 1. / this->u_stretch(); }
+    // Downhill is where the belt surface is lower, i.e. printed earlier, i.e.
+    // the leading edge of the part.  For shear > 0 that is -u.
+    int    downhill_sign() const { return shear > 0. ? -1 : +1; }
+};
+
+// Scale only the `from_axis` component by `factor`, rounding to nearest.
+//
+// Deliberately not MultiPoint::scale(fx, fy) / ExPolygon::scale(fx, fy): those
+// truncate toward zero, which is asymmetric about the origin and loses up to a
+// full coordinate unit per vertex on every round trip.
+ExPolygons belt_scale_u(const ExPolygons &src, const BeltBrimFrame &frame, double factor);
+Polylines  belt_scale_u(const Polylines  &src, const BeltBrimFrame &frame, double factor);
+
+// Into / out of the space where Euclidean offsets equal true on-belt distances.
+inline ExPolygons belt_flatten(const ExPolygons &src, const BeltBrimFrame &frame)
+    { return belt_scale_u(src, frame, frame.u_stretch()); }
+inline ExPolygons belt_unflatten(const ExPolygons &src, const BeltBrimFrame &frame)
+    { return belt_scale_u(src, frame, frame.cos_tilt()); }
+
+// Minkowski sum of `src` with the segment [0, t]: the region swept by sliding
+// `src` along t.  Used to grow the brim downhill for "extra brim width".
+//
+// Implemented as union_(P, P + t, {parallelogram per boundary edge}) over ALL
+// contours including holes, with every parallelogram forced counter-clockwise
+// so the non-zero fill rule closes holes narrower than t along the sweep
+// direction.  A hole survives exactly when it is wider than |t| measured along
+// t - not when it is wider in its narrowest Euclidean direction.
+ExPolygons sweep_ex(const ExPolygons &src, const Point &t);
+
+// Brim region for one already-flattened belt footprint.  All lengths are scaled
+// and measured in the flattened (true on-belt) metric.
+//
+// `has_outer` / `has_inner` are the resolved BrimType: belt printers collapse
+// Auto / Mouse ear / Painted to outer-only, so the caller does that mapping and
+// this function never needs PrintConfig.
+//
+// Two directional extras are applied to the footprint before the outer offset, so
+// each one buys reach in one direction only:
+//
+//   `leading` (leading_brim_length) sweeps the footprint DOWNHILL along the belt,
+//   so every leading-facing edge gains an apron ahead of it.
+//   `lateral`  (extra_brim_width)   sweeps it BOTH WAYS across the belt, widening
+//   the brim sideways without pushing it further ahead or behind.
+//
+// Neither is applied to the inner (hole) ring.
+ExPolygons belt_brim_region(const ExPolygons   &footprint_flat,
+                            bool                has_outer,
+                            bool                has_inner,
+                            coord_t             brim_width,
+                            coord_t             object_gap,
+                            coord_t             leading,
+                            coord_t             lateral,
+                            const BeltBrimFrame &frame);
+
+// Brim line positions for one layer band.
+//
+// Lines sit on a fixed lattice `u_anchor + k * pitch_u` so the on-belt spacing
+// between neighbouring brim lines is constant regardless of how the lattice
+// falls across layer bands.  Snapping to band centres instead would quantise
+// the spacing to whole bands and under-deposit by ~35% at 45 degrees.
+//
+// The band is half-open, [u_lo, u_hi), so every lattice point belongs to
+// exactly one band: none duplicated at a boundary, none dropped.  A band
+// narrower than the pitch simply yields nothing; a band much wider (shallow
+// tilt) yields several lines.
+std::vector<coord_t> belt_brim_line_positions(coord_t u_lo,
+                                              coord_t u_hi,
+                                              coord_t pitch_u,
+                                              coord_t u_anchor);
+
+// ---------------------------------------------------------------- pipeline
+
+// One brim-only layer printed BEFORE the object's first layer, carrying the
+// apron that has to be stuck to the belt ahead of the part.
+//
+// Deliberately not a Layer subclass.  A synthetic Layer would inherit id()
+// semantics that leak into initial-layer temperature selection, the spiral vase
+// probe, gradual interpolation, avoid-crossing-perimeters and cooling, all of
+// which key off Layer::id() == 0 or off a layer's regions.  A plain record
+// carries only what the emitter needs.
+//
+// `height` is the LAYER height, used for the Z move and ordering metadata only.
+// Each extrusion path inside `fills` carries its own height, equal to that
+// line's nozzle-to-belt clearance, which varies across the band.
+struct BeltBrimBand
+{
+    coordf_t                  print_z = 0.;
+    coordf_t                  height  = 0.;
+    // erBrim paths in the object's local slicing frame, untranslated.
+    ExtrusionEntityCollection fills;
+    // Footprint of those paths, for the first-layer convex hull / bbox.
+    ExPolygons                areas;
+};
+
+class PrintObject;
+
+// Generate the belt brim for one object: fills its per-object-layer bands and
+// its apron prologue.  No-op unless PrintObject::has_belt_brim().
+//
+// Runs inside posSupportMaterial rather than the brim step, because the prologue
+// print_z values must exist before ToolOrdering is built at psWipeTower.
+void make_belt_brim(PrintObject &object);
+
+} // namespace Slic3r
+
+#endif // slic3r_BeltBrim_hpp_

src/libslic3r/BeltGCode.cpp

@@ -0,0 +1,76 @@
+#include "BeltGCode.hpp"
+#include "BeltGCodeWriter.hpp"
+#include "BeltTransform.hpp"
+#include "Print.hpp"
+
+namespace Slic3r {
+
+void BeltGCode::init_belt_writer(Print &print, bool is_bbl_printers)
+{
+    if (!print.config().belt_printer.value)
+        return;
+
+    auto belt_writer = std::make_unique<BeltGCodeWriter>();
+    belt_writer->set_is_bbl_machine(is_bbl_printers);
+    // Axis remap and build volume max are set by base GCode after init_belt_writer returns.
+    belt_writer->set_belt_back_transform(print.config());
+    belt_writer->set_machine_frame_transform(print.config());
+    m_writer = std::move(belt_writer);
+}
+
+void BeltGCode::write_belt_header(GCodeOutputStream &file, const Print &print)
+{
+    if (!print.config().belt_printer.value)
+        return;
+
+    const auto &full_cfg = print.full_print_config();
+    // Slicing rotation: the belt tilt (axis + angle) and the single source of truth
+    // for the physical tilt the G-code viewer uses to enable belt view.
+    file.write_format("; belt_slice_rotation = %s\n", full_cfg.opt_serialize("belt_slice_rotation").c_str());
+    file.write_format("; belt_slice_rotation_angle = %.1f\n", print.config().belt_slice_rotation_angle.value);
+    file.write_format("; belt_slice_rotation_global = %d\n", print.config().belt_slice_rotation_global.value ? 1 : 0);
+    // Pre-slice remap configs
+    file.write_format("; preslice_remap_x = %s\n", full_cfg.opt_serialize("preslice_remap_x").c_str());
+    file.write_format("; preslice_remap_y = %s\n", full_cfg.opt_serialize("preslice_remap_y").c_str());
+    file.write_format("; preslice_remap_z = %s\n", full_cfg.opt_serialize("preslice_remap_z").c_str());
+    file.write_format("; preslice_remap_global = %d\n", print.config().preslice_remap_global.value ? 1 : 0);
+    file.write_format("; belt_preslice_global = %d\n", print.config().belt_preslice_global.value ? 1 : 0);
+    // Machine-frame transform: shear (tan) + scale (1/cos) derived from the belt
+    // tilt angle (or belt_frame_tilt_angle when decoupled).
+    file.write_format("; belt_frame_tilt_decouple = %d\n", print.config().belt_frame_tilt_decouple.value ? 1 : 0);
+    file.write_format("; belt_frame_tilt_angle = %.1f\n", print.config().belt_frame_tilt_angle.value);
+}
+
+void BeltGCode::on_set_origin(const PrintObject * /*obj*/, const Point & /*inst_shift*/)
+{
+    // Global pre-slice mode: adjust origin using computed correction.
+    // Transform the origin through the belt pipeline so that
+    // back_transform(T * origin) = origin (correct machine position).
+    //
+    // Flags that trigger this path:
+    //   belt_preslice_global         — full pipeline (rotation * remap) is global
+    //   preslice_remap_global        — only the pre-slice remap is global
+    //   belt_slice_rotation_global   — slicing rotation treated as global (matches
+    //                                  the per-instance Z-offset added in PrintObjectSlice.cpp)
+    // The XY origin adjustment uses the FULL forward transform, because the
+    // back_transform applied during G-code emission is always the inverse of
+    // the full pipeline.
+    bool use_global = m_config.belt_preslice_global.value
+        || (m_config.preslice_remap_global.value
+            && BeltTransformPipeline::has_preslice_remap(m_config))
+        || (m_config.belt_slice_rotation_global.value
+            && m_config.belt_slice_rotation.value != BeltRotationAxis::None
+            && std::abs(m_config.belt_slice_rotation_angle.value) > EPSILON);
+    if (!use_global || !m_config.belt_printer.value)
+        return;
+
+    // Adjust origin: transform through belt forward pipeline so that
+    // the back-transform correctly recovers model-space positions.
+    Transform3d T = BeltTransformPipeline::build_forward_transform(m_config);
+    Vec2d cur_origin = this->origin();
+    Vec3d origin3d(cur_origin.x(), cur_origin.y(), 0.);
+    Vec3d adjusted = T.linear() * origin3d;
+    this->set_origin(Vec2d(adjusted.x(), adjusted.y()));
+}
+
+} // namespace Slic3r

src/libslic3r/BeltGCode.hpp

@@ -0,0 +1,23 @@
+#pragma once
+
+#include "GCode.hpp"
+
+namespace Slic3r {
+
+// Belt-printer-specific GCode export.
+//
+// Inherits from GCode and overrides virtual hooks to:
+// - Create a BeltGCodeWriter instead of a plain GCodeWriter
+// - Write belt configuration to the G-code header
+// - Adjust the origin for global pre-slice transforms when switching instances
+// - Disable arc fitting (G2/G3 not supported on belt printers)
+class BeltGCode : public GCode
+{
+protected:
+    void init_belt_writer(Print &print, bool is_bbl_printers) override;
+    void write_belt_header(GCodeOutputStream &file, const Print &print) override;
+    void on_set_origin(const PrintObject *obj, const Point &inst_shift) override;
+    bool should_disable_arc_fitting() const override { return true; }
+};
+
+} // namespace Slic3r

src/libslic3r/BeltGCodeWriter.cpp

@@ -0,0 +1,277 @@
+#include "BeltGCodeWriter.hpp"
+#include "FirstLayerPlane.hpp"
+#include "Geometry.hpp"
+#include <boost/log/trivial.hpp>
+
+namespace Slic3r {
+
+namespace {
+
+// Decide whether a particular destination point gets first-layer treatment.
+// When the plane evaluator is active, distance from the plane wins; otherwise
+// fall back to the layer-coarse m_is_first_layer flag set by the caller.
+inline bool belt_point_on_first_layer(
+    const FirstLayerPlane *plane,
+    double                 first_layer_thickness_mm,
+    bool                   layer_first_flag,
+    const Vec3d           &point_slicing_mm)
+{
+    if (plane && plane->is_active())
+        return plane->is_first_layer(point_slicing_mm, first_layer_thickness_mm);
+    return layer_first_flag;
+}
+
+} // namespace
+
+// ---- Belt configuration ---------------------------------------------------
+
+void BeltGCodeWriter::set_belt_back_transform(const PrintConfig &config)
+{
+    m_belt_back_transform.init_from_config(config);
+}
+
+void BeltGCodeWriter::set_machine_frame_transform(const PrintConfig &config)
+{
+    m_machine_frame_transform.init_from_config(config);
+}
+
+Vec3d BeltGCodeWriter::to_machine_coords(const Vec3d &pos) const
+{
+    // Step 1+2: To Cartesian (back_transform + axis_remap).
+    // In world-coordinates mode (PA line / PA pattern calibration) the input
+    // already describes a point relative to the belt surface, so the
+    // slicer->world back-transform is skipped and only the machine kinematics
+    // (axis remap + frame shear/scale) are applied.
+    Vec3d after_back = m_world_coordinates ? pos : m_belt_back_transform.apply(pos);
+    Vec3d result     = apply_axis_remap(after_back);
+    Vec3d after_remap = result;
+    // Step 3: Machine-frame transform (belt frame tilt) applied LAST so it acts
+    // as a global linear transform on the placed coords.
+    Vec3d final = m_machine_frame_transform.apply(result);
+
+    // [BELT-DEBUG] One-shot log per layer transition (i.e. when the input Z
+    // crosses an integer mm boundary) to keep the log volume manageable while
+    // still capturing one sample per ~5 layers.  Shows the full pipeline so
+    // Case A vs Case B can be compared step-by-step.
+    static thread_local int s_last_logged_z = std::numeric_limits<int>::min();
+    int z_bucket = static_cast<int>(std::floor(pos.z() * 5.0));  // every 0.2mm
+    if (z_bucket != s_last_logged_z) {
+        s_last_logged_z = z_bucket;
+        BOOST_LOG_TRIVIAL(trace) << "[BELT-DEBUG] to_machine_coords"
+            << " slicer_in=(" << pos.x() << "," << pos.y() << "," << pos.z() << ")"
+            << " after_back=(" << after_back.x() << "," << after_back.y() << "," << after_back.z() << ")"
+            << " after_remap=(" << after_remap.x() << "," << after_remap.y() << "," << after_remap.z() << ")"
+            << " final=(" << final.x() << "," << final.y() << "," << final.z() << ")"
+            << " mft_active=" << m_machine_frame_transform.is_active()
+            << " back_active=" << m_belt_back_transform.is_active();
+    }
+    return final;
+}
+
+// ---- Overridden movement methods ------------------------------------------
+
+std::string BeltGCodeWriter::travel_to_xy(const Vec2d &point, const std::string &comment)
+{
+    m_pos(0) = point(0);
+    m_pos(1) = point(1);
+
+    this->set_current_position_clear(true);
+    Vec2d point_on_plate = { point(0) - m_x_offset, point(1) - m_y_offset };
+
+    // Belt printer: transform to machine coordinates (XY travel also needs Z due to YZ rotation)
+    Vec3d machine = to_machine_coords(Vec3d(point_on_plate.x(), point_on_plate.y(), m_pos.z()));
+
+    GCodeG1Formatter w;
+    w.emit_xyz(machine);
+    const bool first_layer_for_point = belt_point_on_first_layer(
+        m_first_layer_plane, m_first_layer_thickness_mm, m_is_first_layer,
+        Vec3d(point.x(), point.y(), m_pos.z()));
+    auto speed = first_layer_for_point
+        ? this->config.get_abs_value_at("initial_layer_travel_speed", m_cached_extruder_idx)
+        : this->config.travel_speed.get_at(m_cached_extruder_idx);
+    w.emit_f(speed * 60.0);
+    w.emit_comment(GCodeWriter::full_gcode_comment, comment);
+    return w.string();
+}
+
+std::string BeltGCodeWriter::lazy_lift(LiftType lift_type, bool spiral_vase)
+{
+    // Belt printer: force NormalLift since SpiralLift and SlopeLift compute
+    // slope angles that don't account for the YZ coordinate rotation.
+    return GCodeWriter::lazy_lift(LiftType::NormalLift, spiral_vase);
+}
+
+std::string BeltGCodeWriter::eager_lift(const LiftType type)
+{
+    // Belt printer: force NormalLift (SpiralLift/SlopeLift don't account for YZ rotation).
+    return GCodeWriter::eager_lift(LiftType::NormalLift);
+}
+
+std::string BeltGCodeWriter::_travel_to_z(double z, const std::string &comment)
+{
+    m_pos(2) = z;
+
+    double speed = this->config.travel_speed_z.get_at(m_cached_extruder_idx);
+    if (speed == 0.) {
+        const bool first_layer_for_point = belt_point_on_first_layer(
+            m_first_layer_plane, m_first_layer_thickness_mm, m_is_first_layer,
+            Vec3d(m_pos.x(), m_pos.y(), z));
+        speed = first_layer_for_point ? this->config.get_abs_value_at("initial_layer_travel_speed", m_cached_extruder_idx)
+                                      : this->config.travel_speed.get_at(m_cached_extruder_idx);
+    }
+
+    // Belt printer: a Z-only move in slicing frame needs to emit both Y and Z in machine coords.
+    Vec3d machine = to_machine_coords(Vec3d(m_pos.x() - m_x_offset, m_pos.y() - m_y_offset, z));
+
+    GCodeG1Formatter w;
+    w.emit_xyz(machine);
+    w.emit_f(speed * 60.0);
+    w.emit_comment(GCodeWriter::full_gcode_comment, comment);
+    return w.string();
+}
+
+std::string BeltGCodeWriter::extrude_to_xy(const Vec2d &point, double dE, const std::string &comment, bool force_no_extrusion)
+{
+    m_pos(0) = point(0);
+    m_pos(1) = point(1);
+    if (std::abs(dE) <= std::numeric_limits<double>::epsilon())
+        force_no_extrusion = true;
+
+    if (!force_no_extrusion)
+        filament()->extrude(dE);
+
+    Vec2d point_on_plate = { point(0) - m_x_offset, point(1) - m_y_offset };
+
+    // Belt printer: transform and emit XYZ (Y and Z are coupled)
+    Vec3d machine = to_machine_coords(Vec3d(point_on_plate.x(), point_on_plate.y(), m_pos.z()));
+
+    GCodeG1Formatter w;
+    w.emit_xyz(machine);
+    if (!force_no_extrusion)
+        w.emit_e(filament()->E());
+    w.emit_comment(GCodeWriter::full_gcode_comment, comment);
+    return w.string();
+}
+
+std::string BeltGCodeWriter::extrude_to_xyz(const Vec3d &point, double dE, const std::string &comment, bool force_no_extrusion)
+{
+    m_pos = point;
+    m_lifted = 0;
+    if (!force_no_extrusion)
+        filament()->extrude(dE);
+
+    Vec3d point_on_plate = { point(0) - m_x_offset, point(1) - m_y_offset, point(2) };
+    point_on_plate = to_machine_coords(point_on_plate);
+
+    GCodeG1Formatter w;
+    w.emit_xyz(point_on_plate);
+    if (!force_no_extrusion)
+        w.emit_e(filament()->E());
+    w.emit_comment(GCodeWriter::full_gcode_comment, comment);
+    return w.string();
+}
+
+std::string BeltGCodeWriter::travel_to_xyz(const Vec3d &point, const std::string &comment, bool force_z)
+{
+    // Belt-specific override of travel_to_xyz.
+    // Key differences from base:
+    // 1. All coordinates go through to_machine_coords()
+    // 2. Always emit full XYZ (can't split XY and Z due to coupling)
+    // 3. Lift type forced to NormalLift (handled by lazy_lift/eager_lift overrides)
+
+    Vec3d dest_point = point;
+    const bool first_layer_for_point = belt_point_on_first_layer(
+        m_first_layer_plane, m_first_layer_thickness_mm, m_is_first_layer, point);
+    auto travel_speed =
+        first_layer_for_point ? this->config.get_abs_value_at("initial_layer_travel_speed", m_cached_extruder_idx)
+                              : this->config.travel_speed.get_at(m_cached_extruder_idx);
+
+    // Handle pending z_hop
+    if (std::abs(m_to_lift) > EPSILON) {
+        assert(std::abs(m_lifted) < EPSILON);
+        if ((!this->is_current_position_clear() || m_pos != dest_point) &&
+            m_to_lift + m_pos(2) > point(2)) {
+            m_lifted = m_to_lift + m_pos(2) - point(2);
+            dest_point(2) = m_to_lift + m_pos(2);
+        }
+        m_to_lift = 0.;
+
+        std::string slop_move;
+        Vec3d source = { m_pos(0) - m_x_offset, m_pos(1) - m_y_offset, m_pos(2) };
+        Vec3d target = { dest_point(0) - m_x_offset, dest_point(1) - m_y_offset, dest_point(2) };
+        Vec3d delta = target - source;
+        Vec2d delta_no_z = { delta(0), delta(1) };
+
+        if (delta(2) > 0 && delta_no_z.norm() != 0.0f) {
+            // Belt: SpiralLift and SlopeLift are disabled (lazy_lift forces NormalLift),
+            // but handle NormalLift and fallthrough.
+            if (m_to_lift_type == LiftType::SlopeLift &&
+                this->is_current_position_clear() &&
+                atan2(delta(2), delta_no_z.norm()) < this->filament()->travel_slope()) {
+                Vec2d temp = delta_no_z.normalized() * delta(2) / tan(this->filament()->travel_slope());
+                Vec3d slope_top_point = Vec3d(temp(0), temp(1), delta(2)) + source;
+                slope_top_point = to_machine_coords(slope_top_point);
+                GCodeG1Formatter w0;
+                w0.emit_xyz(slope_top_point);
+                w0.emit_f(travel_speed * 60.0);
+                w0.emit_comment(GCodeWriter::full_gcode_comment, comment);
+                slop_move = w0.string();
+            }
+            else if (m_to_lift_type == LiftType::NormalLift && this->is_current_position_clear()) {
+                // Only lift-in-place when the current position is known. On a normal
+                // printer _travel_to_z emits a Z-only move, but in belt mode Z is coupled
+                // to Y/X, so _travel_to_z re-emits the current m_pos through the belt
+                // shear. At print start (and after custom gcode) m_pos.xy is still the
+                // uninitialised origin (0,0), which shears into a bogus machine point
+                // (e.g. X=bed_max, Y=layer_z) far up the gantry. Skipping the separate
+                // lift here is safe: there is nothing to lift over yet, and the
+                // xy_z_move below travels straight to the destination with full XYZ,
+                // establishing the correct position. This mirrors the SlopeLift branch
+                // above, which already guards on is_current_position_clear().
+                slop_move = _travel_to_z(target.z(), "normal lift Z");
+            }
+        }
+
+        std::string xy_z_move;
+        {
+            Vec3d emit_target = to_machine_coords(target);
+            GCodeG1Formatter w0;
+            // Belt mode: always emit full XYZ since Y and Z are coupled
+            w0.emit_xyz(emit_target);
+            w0.emit_f(travel_speed * 60.0);
+            w0.emit_comment(GCodeWriter::full_gcode_comment, comment);
+            xy_z_move = w0.string();
+        }
+        m_pos = dest_point;
+        this->set_current_position_clear(true);
+        return slop_move + xy_z_move;
+    }
+    else if (!force_z && !this->will_move_z(point(2))) {
+        double nominal_z = m_pos(2) - m_lifted;
+        m_lifted -= (point(2) - nominal_z);
+        if (std::abs(m_lifted) < EPSILON)
+            m_lifted = 0.;
+        this->set_current_position_clear(true);
+        return this->travel_to_xy(to_2d(point));
+    }
+    else {
+        m_lifted = 0;
+    }
+
+    Vec3d point_on_plate = { dest_point(0) - m_x_offset, dest_point(1) - m_y_offset, dest_point(2) };
+    point_on_plate = to_machine_coords(point_on_plate);
+
+    // Belt mode: always emit full XYZ
+    GCodeG1Formatter w;
+    w.emit_xyz(point_on_plate);
+    // Use the first-layer-aware travel_speed computed at the top of this function,
+    // not the raw config travel_speed, so initial-layer travels are correctly slowed.
+    w.emit_f(travel_speed * 60.0);
+    w.emit_comment(GCodeWriter::full_gcode_comment, comment);
+
+    m_pos = dest_point;
+    this->set_current_position_clear(true);
+    return w.string();
+}
+
+} // namespace Slic3r

src/libslic3r/BeltGCodeWriter.hpp

@@ -0,0 +1,64 @@
+#pragma once
+
+#include "GCodeWriter.hpp"
+#include "GCode/BeltBackTransform.hpp"
+#include "GCode/MachineFrameTransform.hpp"
+
+namespace Slic3r {
+
+class FirstLayerPlane;
+
+// Belt-printer-specific GCode writer.
+//
+// Inherits from GCodeWriter and overrides movement methods to apply
+// coordinate transformation (back-transform, axis remap, machine-frame
+// transform) and emit coupled XYZ moves (Y and Z are coupled due to belt tilt).
+class BeltGCodeWriter : public GCodeWriter
+{
+public:
+    BeltGCodeWriter() : GCodeWriter() {}
+
+    // Belt configuration (axis remap is inherited from GCodeWriter)
+    void set_belt_back_transform(const PrintConfig &config);
+    void set_machine_frame_transform(const PrintConfig &config);
+    Vec3d to_machine_coords(const Vec3d &pos) const;
+
+    // World-coordinates mode: incoming coordinates are treated as points
+    // relative to the physical belt surface (X across, Y along the belt,
+    // Z height above it) instead of slicing-frame coordinates — the
+    // slicer->world back-transform is skipped. Used by the PA line / PA
+    // pattern calibration generators, whose logical bed coordinates describe
+    // first-layer drawings on the build surface.
+    void set_world_coordinates(bool enable) { m_world_coordinates = enable; }
+
+    // First-layer plane: when set to a non-null active evaluator, travel
+    // speed selection consults the plane per-move and uses
+    // initial_layer_travel_speed for points within first_layer_height_mm
+    // of the plane (regardless of slicing layer index).
+    void set_first_layer_plane(const FirstLayerPlane *plane,
+                               double first_layer_height_mm) {
+        m_first_layer_plane         = plane;
+        m_first_layer_thickness_mm  = first_layer_height_mm;
+    }
+
+    // Overridden movement methods
+    std::string travel_to_xy(const Vec2d &point, const std::string &comment = std::string()) override;
+    std::string travel_to_xyz(const Vec3d &point, const std::string &comment = std::string(), bool force_z = false) override;
+    std::string extrude_to_xy(const Vec2d &point, double dE, const std::string &comment = std::string(), bool force_no_extrusion = false) override;
+    std::string extrude_to_xyz(const Vec3d &point, double dE, const std::string &comment = std::string(), bool force_no_extrusion = false) override;
+    std::string lazy_lift(LiftType lift_type = LiftType::NormalLift, bool spiral_vase = false) override;
+    std::string eager_lift(const LiftType type) override;
+
+protected:
+    std::string _travel_to_z(double z, const std::string &comment) override;
+
+private:
+    BeltBackTransform     m_belt_back_transform;
+    MachineFrameTransform m_machine_frame_transform;
+    bool                  m_world_coordinates = false;
+    // Borrowed pointer; lifetime owned by GCode.  null = inactive.
+    const FirstLayerPlane *m_first_layer_plane = nullptr;
+    double          m_first_layer_thickness_mm = 0.;
+};
+
+} // namespace Slic3r

src/libslic3r/BeltPurge.cpp

@@ -0,0 +1,346 @@
+// ORCA-Belt: backend of the belt purge tower (the belt replacement for the
+// classic wipe/prime tower).
+//
+// Kept in its own translation unit so the belt-purge logic stays out of the way
+// of unrelated upstream changes to Print.cpp / PrintObjectSlice.cpp and carries
+// no regression risk for normal printers: none of these methods do anything
+// unless the print is a belt printer with the belt purge tower enabled.
+//
+//   Print::has_belt_purge_tower()      - is the belt purge tower active?
+//   Print::_align_belt_purge_layers()  - snap the prism's layer grid onto the
+//                                        printed objects' grid
+//   Print::_plan_belt_purge()          - route filament-change purging into the
+//                                        prism (flush-into-objects), no wipe tower
+//   PrintObject::belt_shift_layer_grid()      - shift a sliced layer grid
+//   PrintObject::belt_truncate_layers_above() - cancel the prism past the last swap
+//
+// (Declarations live in Print.hpp alongside the rest of the Print interface.)
+
+#include "Print.hpp"
+#include "PrintConfig.hpp"
+#include "Exception.hpp"
+#include "GCode/ToolOrdering.hpp"
+#include "Layer.hpp"
+#include "ExtrusionEntity.hpp"
+#include "ExtrusionEntityCollection.hpp"
+#include "I18N.hpp"
+#include "format.hpp"
+#include "LocalesUtils.hpp"
+#include "libslic3r.h"
+
+#include <algorithm>
+#include <cmath>
+#include <limits>
+
+#include <boost/log/trivial.hpp>
+
+namespace Slic3r {
+
+// Belt purge prism: purging after filament changes is routed into a sliced
+// prism object via the flush-into-objects machinery instead of a wipe tower.
+bool Print::has_belt_purge_tower() const
+{
+    // Its own purge-tower "type", gated by the belt-only enable_belt_purge_tower
+    // option (not the classic enable_prime_tower).
+    if (!(m_config.belt_printer.value
+          && m_config.enable_belt_purge_tower.value
+          && !m_config.spiral_mode.value
+          && m_config.filament_diameter.values.size() > 1))
+        return false;
+
+    return std::any_of(m_objects.begin(), m_objects.end(), [](const PrintObject *object) {
+        return object->config().belt_purge_tower_object.value;
+    });
+}
+
+// Belt mode: align ALL objects on the plate (the printed objects AND the purge
+// prism) onto one common layer grid, so the prism can absorb every toolchange.
+//
+// After belt slicing each object's layer print_z carries a per-object global z
+// offset (mesh-vertex-scan belt_z_shift + instance-Y-dependent terms), so
+// objects at different belt-Y positions get layer grids with DIFFERENT residues
+// (mod layer height). Purge marking looks absorbers up with
+// get_layer_at_printz(lt.print_z, EPSILON), so a toolchange on object B only
+// absorbs into the prism if the prism has a layer at B's print_z. Snapping only
+// the prism to one object therefore worked for a single (assembled) multi-color
+// object but failed with multiple separate objects — the prism could follow only
+// one grid, and toolchanges on the others went unabsorbed ("multiple layer
+// grids" warning).
+//
+// Fix: pick one reference grid (the tallest object) and shift every object onto
+// it. Each shift is at most half a layer height — a sub-100µm move along the
+// belt, the very same mechanism the per-object global_z_offset already uses, and
+// it keeps each object internally consistent (belt_shift_layer_grid moves the
+// object's layers, its support layers, and its belt floor together). Equal layer
+// height across objects is enforced by Print::validate(), so once residues match
+// every object steps on the same lattice {ref_offset + k*h} and every toolchange
+// layer coincides with a prism layer.
+void Print::_align_belt_purge_layers()
+{
+    PrintObject *prism = nullptr;
+    for (PrintObject *po : m_objects)
+        if (po->config().belt_purge_tower_object.value && !po->layers().empty()) {
+            prism = po;
+            break;
+        }
+    if (prism == nullptr || prism->layers().empty())
+        return;
+
+    const double h = prism->config().layer_height.value;
+    if (h <= EPSILON)
+        return;
+
+    // Grid residue of an object's layer grid: identical for all of an object's
+    // layers above the first since they step by h.
+    auto grid_offset = [h](const PrintObject *po) -> double {
+        if (po->layers().empty())
+            return 0.;
+        const double z = po->layers().front()->print_z;
+        return z - std::floor(z / h) * h; // in [0, h)
+    };
+
+    // Reference grid: the tallest non-prism object (proxy for the object with
+    // the most toolchange layers — minimizes how far the rest must move).
+    const PrintObject *ref     = nullptr;
+    double             ref_top = -std::numeric_limits<double>::max();
+    for (const PrintObject *po : m_objects) {
+        if (po->config().belt_purge_tower_object.value || po->layers().empty())
+            continue;
+        const double top = po->layers().back()->print_z;
+        if (top > ref_top) {
+            ref_top = top;
+            ref     = po;
+        }
+    }
+    if (ref == nullptr)
+        return;
+
+    const double ref_offset = grid_offset(ref);
+
+    // Snap every object (printed objects AND the prism) onto the reference grid.
+    for (PrintObject *po : m_objects) {
+        if (po->layers().empty())
+            continue;
+        double delta = ref_offset - grid_offset(po);
+        if (delta > 0.5 * h)
+            delta -= h;
+        else if (delta <= -0.5 * h)
+            delta += h;
+        po->belt_shift_layer_grid(delta); // no-op for the reference object (delta ~ 0)
+    }
+
+    BOOST_LOG_TRIVIAL(debug) << "[BELT-DEBUG] purge grid align: snapped " << m_objects.size()
+        << " objects onto ref grid offset=" << ref_offset
+        << " (ref=" << ref->model_object()->name << ")";
+}
+
+// Belt mode replacement for _make_wipe_tower(): plan filament-change purging
+// into the belt purge prism (and any other flush_into_* object) using the
+// flush-into-objects machinery, without generating classic wipe tower G-code.
+// The toolchange itself is emitted by GCode::set_extruder() via the
+// change_filament_gcode macro; the overrides marked here make the new
+// filament's first extrusions land in the purge prism.
+void Print::_plan_belt_purge()
+{
+    m_wipe_tower_data.clear();
+
+    // psWipeTower may be invalidated without posSlice (for example after a
+    // filament-map or tool-ordering change). Restore a prism shortened by the
+    // previous plan so a newly higher toolchange can use its original layers.
+    for (PrintObject *po : m_objects)
+        if (po->config().belt_purge_tower_object.value)
+            po->belt_restore_truncated_layers();
+
+    // Must run before ToolOrdering is built: LayerTools merge per-object layer
+    // print_z values, and the prism only absorbs purge where its (snapped)
+    // layers coincide with the toolchange layers.
+    this->_align_belt_purge_layers();
+
+    const unsigned int number_of_extruders = (unsigned int) m_config.filament_colour.values.size();
+
+    // No initial priming extrusions: there is no tower to prime on.
+    m_wipe_tower_data.tool_ordering = ToolOrdering(*this, (unsigned int) -1, false);
+    m_wipe_tower_data.tool_ordering.sort_and_build_data(*this, (unsigned int) -1, false);
+
+    if (m_wipe_tower_data.tool_ordering.empty() || m_wipe_tower_data.tool_ordering.last_extruder() == unsigned(-1))
+        throw Slic3r::SlicingError("The print is empty. The model is not printable with current print settings.");
+
+    if (!m_wipe_tower_data.tool_ordering.has_wipe_tower())
+        // No toolchanges anywhere, nothing to purge.
+        return;
+
+    this->throw_if_canceled();
+
+    // Flush volumes per filament pair, mirroring the generic wipe tower path:
+    // full flush matrix for single extruder multi material with purging enabled,
+    // plain prime volume otherwise.
+    std::vector<float> flush_matrix(cast<float>(
+        get_flush_volumes_matrix(m_config.flush_volumes_matrix.values, 0, m_config.nozzle_diameter.values.size())));
+    std::vector<std::vector<float>> wipe_volumes;
+    for (unsigned int i = 0; i < number_of_extruders; ++i)
+        wipe_volumes.push_back(std::vector<float>(flush_matrix.begin() + i * number_of_extruders,
+                                                  flush_matrix.begin() + (i + 1) * number_of_extruders));
+    const bool  use_flush_matrix = m_config.purge_in_prime_tower && m_config.single_extruder_multi_material;
+    const float flush_multiplier = (float) m_config.flush_multiplier.get_at(0);
+
+    // Cancel the purge prism early: pre-scan the tool ordering for the highest
+    // print_z that actually has a toolchange, then drop the prism's layers above
+    // it so the tower stops at the last color swap (saves filament/time). This
+    // MUST happen before the marking loop below: ensure_perimeters_infills_order
+    // force-overrides the prism's extrusions on every layer (it is a dedicated
+    // flush object), so truncating afterwards would leave dangling overrides
+    // pointing into deleted layers.
+    {
+        double       last_tc_z   = -1.;
+        unsigned int cur_ext     = m_wipe_tower_data.tool_ordering.first_extruder();
+        for (const auto &lt : m_wipe_tower_data.tool_ordering.layer_tools())
+            for (const unsigned int e : lt.extruders)
+                if (e != cur_ext) { last_tc_z = lt.print_z; cur_ext = e; }
+        if (last_tc_z >= 0.)
+            for (PrintObject *po : m_objects)
+                if (po->config().belt_purge_tower_object.value && !po->layers().empty()) {
+                    po->belt_truncate_layers_above(last_tc_z);
+                    break;
+                }
+    }
+
+    // Diagnostic: the prism only absorbs purge at toolchange layers whose
+    // print_z coincides with one of its own layers. Compare the prism's layer
+    // print_z range to the toolchange print_z range and count how many
+    // toolchange layers actually land on a prism layer. This distinguishes a
+    // range/grid-alignment failure (no coverage) from a capacity shortfall
+    // (covered but not enough cross-section).
+    PrintObject *prism_po = nullptr;
+    for (PrintObject *po : m_objects)
+        if (po->config().belt_purge_tower_object.value && !po->layers().empty()) { prism_po = po; break; }
+    const PrintObject *diag_prism = prism_po;
+    if (diag_prism != nullptr)
+        BOOST_LOG_TRIVIAL(warning) << "[BELT-DEBUG] purge prism layer range print_z=["
+            << diag_prism->layers().front()->print_z << ", " << diag_prism->layers().back()->print_z
+            << "] nlayers=" << diag_prism->layers().size();
+    int tc_layers = 0, tc_layers_covered = 0;
+
+    float  total_leftover      = 0.f;
+    float  worst_layer_leftover = 0.f;
+    double worst_layer_z       = 0.;
+
+    unsigned int current_extruder_id = m_wipe_tower_data.tool_ordering.first_extruder();
+    for (auto &layer_tools : m_wipe_tower_data.tool_ordering.layer_tools()) {
+        float layer_leftover = 0.f;
+        bool  layer_has_tc   = false;
+        for (const unsigned int extruder_id : layer_tools.extruders) {
+            if (extruder_id == current_extruder_id)
+                continue;
+            if (!layer_has_tc) {
+                layer_has_tc = true;
+                ++tc_layers;
+                if (diag_prism != nullptr && diag_prism->get_layer_at_printz(layer_tools.print_z, EPSILON) != nullptr)
+                    ++tc_layers_covered;
+            }
+            float volume_to_wipe = use_flush_matrix ?
+                wipe_volumes[current_extruder_id][extruder_id] * flush_multiplier :
+                (float) m_config.prime_volume;
+            float leftover = layer_tools.wiping_extrusions().mark_wiping_extrusions(*this, current_extruder_id, extruder_id,
+                                                                                    volume_to_wipe);
+            BOOST_LOG_TRIVIAL(trace) << "[BELT-DEBUG] purge toolchange print_z=" << layer_tools.print_z
+                << " filament " << current_extruder_id << "->" << extruder_id
+                << " requested=" << volume_to_wipe
+                << " absorbed=" << volume_to_wipe - leftover
+                << " leftover=" << leftover;
+            layer_leftover += leftover;
+            current_extruder_id = extruder_id;
+        }
+
+        // Do not destructively remove unclaimed fill entities here. psWipeTower
+        // can rerun without regenerating infill, and a later tool ordering may
+        // need entities that were unclaimed by the previous plan.
+        layer_tools.wiping_extrusions().ensure_perimeters_infills_order(*this);
+        if (layer_leftover > 0.f) {
+            total_leftover += layer_leftover;
+            if (layer_leftover > worst_layer_leftover) {
+                worst_layer_leftover = layer_leftover;
+                worst_layer_z        = layer_tools.print_z;
+            }
+        }
+        this->throw_if_canceled();
+    }
+
+    BOOST_LOG_TRIVIAL(warning) << "[BELT-DEBUG] purge coverage: " << tc_layers_covered << "/" << tc_layers
+        << " toolchange layers land on a prism layer"
+        << (tc_layers > 0 && tc_layers_covered == 0 ? " (RANGE/GRID MISALIGNMENT — prism absorbs nothing)" :
+            tc_layers_covered < tc_layers ? " (partial coverage)" : " (full coverage)");
+
+    if (total_leftover > 1.f) {
+        this->active_step_add_warning(
+            PrintStateBase::WarningLevel::CRITICAL,
+            Slic3r::format(_u8L("The belt purge tower cannot absorb the full purge volume: %1% mm³ in total could not "
+                                "be purged (worst layer: %2% mm³ at height %3%). The print may show color bleeding. "
+                                "Increase the belt purge tower width, or reduce flushing volumes."),
+                           int(std::ceil(total_leftover)), int(std::ceil(worst_layer_leftover)),
+                           Slic3r::float_to_string_decimal_point(worst_layer_z, 2)));
+        BOOST_LOG_TRIVIAL(warning) << "[BELT-DEBUG] purge planning leftover total=" << total_leftover
+            << " worst_layer=" << worst_layer_leftover << " at print_z=" << worst_layer_z;
+    }
+}
+
+// Belt mode: shift the sliced layer grid by delta. Mirrors the global_z_offset
+// application in slice() — layer print_z and belt_floor_z_shift move together
+// so belt floor clipping stays consistent with the shifted grid. Used by
+// Print::_align_belt_purge_layers() to snap the purge prism onto the printed
+// objects' layer grid; |delta| <= half a layer height, i.e. a sub-layer shift
+// of the prism along the belt.
+void PrintObject::belt_shift_layer_grid(double delta)
+{
+    if (std::abs(delta) < EPSILON)
+        return;
+    for (Layer *layer : m_layers)
+        layer->print_z += delta;
+    for (SupportLayer *layer : m_support_layers)
+        layer->print_z += delta;
+    m_slicing_params.belt_floor_z_shift += delta;
+    BOOST_LOG_TRIVIAL(trace) << "[BELT-DEBUG] belt_shift_layer_grid"
+        << " obj=" << this->model_object()->name
+        << " delta=" << delta
+        << " first_layer.print_z=" << (m_layers.empty() ? 0. : m_layers.front()->print_z);
+}
+
+// Belt mode: drop layers strictly above z (used to cancel the purge prism early
+// once there are no more toolchanges above z, so the tower stops at the last
+// color swap instead of wasting filament up the rest of the belt). Each layer's
+// cross-section is already sliced, so removing upper layers does not affect the
+// last toolchange's coverage. Deletes the Layer objects and clears the new top
+// layer's upper-layer link. Returns the number of layers removed.
+size_t PrintObject::belt_truncate_layers_above(coordf_t z)
+{
+    // A repeated plan always starts from the restored full layer set.
+    assert(m_belt_truncated_layers.empty());
+    size_t keep = m_layers.size();
+    while (keep > 0 && m_layers[keep - 1]->print_z > z + EPSILON)
+        --keep;
+    if (keep >= m_layers.size())
+        return 0;
+    const size_t removed = m_layers.size() - keep;
+    m_belt_truncated_layers.assign(m_layers.begin() + keep, m_layers.end());
+    m_layers.resize(keep);
+    if (!m_layers.empty())
+        m_layers.back()->upper_layer = nullptr;
+    BOOST_LOG_TRIVIAL(debug) << "[BELT-DEBUG] truncate purge prism above print_z=" << z
+        << " kept=" << keep << " removed=" << removed
+        << " new_top=" << (m_layers.empty() ? 0. : m_layers.back()->print_z);
+    return removed;
+}
+
+void PrintObject::belt_restore_truncated_layers()
+{
+    if (m_belt_truncated_layers.empty())
+        return;
+
+    m_layers.insert(m_layers.end(), m_belt_truncated_layers.begin(), m_belt_truncated_layers.end());
+    m_belt_truncated_layers.clear();
+    for (size_t i = 0; i < m_layers.size(); ++i) {
+        m_layers[i]->lower_layer = i == 0 ? nullptr : m_layers[i - 1];
+        m_layers[i]->upper_layer = i + 1 < m_layers.size() ? m_layers[i + 1] : nullptr;
+    }
+}
+
+} // namespace Slic3r

src/libslic3r/BeltSliceStrategy.cpp

@@ -0,0 +1,143 @@
+#include "BeltSliceStrategy.hpp"
+#include "Model.hpp"
+
+#include <limits>
+
+#include <boost/log/trivial.hpp>
+#ifdef SLIC3R_BELT_DIAGNOSTIC_LOG
+#include <iomanip>
+#include <sstream>
+#include <thread>
+#endif
+
+namespace Slic3r {
+
+void BeltSliceStrategy::apply_preslice_transforms(Transform3d           &trafo,
+                                                  const PrintConfig     &config,
+                                                  const ModelVolumePtrs &model_volumes,
+                                                  double                *out_belt_min_z)
+{
+    // 1. Standalone pre-slice axis remap (works without belt mode).
+    const bool has_remap = BeltTransformPipeline::has_preslice_remap(config);
+    if (has_remap)
+        trafo = BeltTransformPipeline::build_preslice_remap(config) * trafo;
+
+    // 2. Belt rotation — the sole mesh-side belt transform (matching
+    //    BeltTransformPipeline::build_forward_transform).  Only active in
+    //    belt-printer mode.
+    bool has_rotation = false;
+    if (config.belt_printer.value) {
+        const Matrix3d rot = BeltTransformPipeline::build_rotation_matrix(config, &has_rotation);
+        if (has_rotation) {
+            Transform3d belt_xform = Transform3d::Identity();
+            belt_xform.linear() = rot;
+            trafo = belt_xform * trafo;
+        }
+    }
+
+    if (!has_remap && !has_rotation)
+        return;
+
+    // 3. Z-shift — detect if the mesh clips below the build plate after the
+    // transforms and lift it.  Each mesh vertex must be brought into object space
+    // via mv->get_matrix() before applying the full trafo (which is in object
+    // space).  Missing this on assemblies (where per-volume get_matrix() positions
+    // each volume within the object) would compute min_z against mesh-local vertex
+    // coordinates rather than object-space coordinates, so volumes translated along
+    // the slicer's Z axis would be silently excluded from the bound check.
+#ifdef SLIC3R_BELT_DIAGNOSTIC_LOG
+    // Capture the incoming trafo for diagnostic logging.
+    // This is the slicer-frame transform AFTER remap + rotation but BEFORE z_shift.
+    const Transform3d trafo_pre_shift = trafo;
+    auto log_mat = [](const Matrix3d &m) {
+        std::ostringstream ss;
+        ss << std::fixed << std::setprecision(4);
+        ss << "[[" << m(0,0) << "," << m(0,1) << "," << m(0,2) << "],"
+           << "["  << m(1,0) << "," << m(1,1) << "," << m(1,2) << "],"
+           << "["  << m(2,0) << "," << m(2,1) << "," << m(2,2) << "]]";
+        return ss.str();
+    };
+    auto log_vec3 = [](const Vec3d &v) {
+        std::ostringstream ss;
+        ss << std::fixed << std::setprecision(4);
+        ss << "(" << v.x() << "," << v.y() << "," << v.z() << ")";
+        return ss.str();
+    };
+    BOOST_LOG_TRIVIAL(trace) << "[BELT-DEBUG] apply_preslice_transforms enter"
+        << " has_rotation=" << has_rotation
+        << " has_remap=" << has_remap
+        << " trafo.linear=" << log_mat(trafo_pre_shift.linear())
+        << " trafo.translation=" << log_vec3(trafo_pre_shift.translation())
+        << " volumes=" << model_volumes.size();
+#endif
+
+    double min_z = std::numeric_limits<double>::max();
+#ifdef SLIC3R_BELT_DIAGNOSTIC_LOG
+    int vol_idx = 0;
+#endif
+    for (const ModelVolume *mv : model_volumes) {
+#ifdef SLIC3R_BELT_DIAGNOSTIC_LOG
+        if (!mv->is_model_part()) { ++vol_idx; continue; }
+#else
+        if (!mv->is_model_part()) continue;
+#endif
+        Transform3d vol_trafo = trafo * mv->get_matrix();
+        const auto &its = mv->mesh().its;
+#ifdef SLIC3R_BELT_DIAGNOSTIC_LOG
+        // Per-volume bbox in mesh-frame and post-trafo slicer-frame.
+        Vec3d mesh_min(std::numeric_limits<double>::max(), std::numeric_limits<double>::max(), std::numeric_limits<double>::max());
+        Vec3d mesh_max(std::numeric_limits<double>::lowest(), std::numeric_limits<double>::lowest(), std::numeric_limits<double>::lowest());
+        Vec3d slicer_min(std::numeric_limits<double>::max(), std::numeric_limits<double>::max(), std::numeric_limits<double>::max());
+        Vec3d slicer_max(std::numeric_limits<double>::lowest(), std::numeric_limits<double>::lowest(), std::numeric_limits<double>::lowest());
+        double vol_min_z = std::numeric_limits<double>::max();
+#endif
+        for (const stl_vertex &v : its.vertices) {
+            Vec3d vm = v.cast<double>();
+            Vec3d pt = vol_trafo * vm;
+            min_z = std::min(min_z, pt.z());
+#ifdef SLIC3R_BELT_DIAGNOSTIC_LOG
+            mesh_min = mesh_min.cwiseMin(vm);
+            mesh_max = mesh_max.cwiseMax(vm);
+            slicer_min = slicer_min.cwiseMin(pt);
+            slicer_max = slicer_max.cwiseMax(pt);
+            vol_min_z = std::min(vol_min_z, pt.z());
+#endif
+        }
+#ifdef SLIC3R_BELT_DIAGNOSTIC_LOG
+        BOOST_LOG_TRIVIAL(trace) << "[BELT-DEBUG]   vol[" << vol_idx
+            << "] id=" << mv->id().id << " name='" << mv->name << "'"
+            << " mesh_bbox_min=" << log_vec3(mesh_min) << " mesh_bbox_max=" << log_vec3(mesh_max)
+            << " get_matrix.translation=" << log_vec3(mv->get_matrix().translation())
+            << " slicer_bbox_min=" << log_vec3(slicer_min) << " slicer_bbox_max=" << log_vec3(slicer_max)
+            << " vol_min_z=" << vol_min_z;
+        ++vol_idx;
+#endif
+    }
+    const double z_shift_val = (min_z < 0. && min_z != std::numeric_limits<double>::max()) ? -min_z : 0.;
+#ifdef SLIC3R_BELT_DIAGNOSTIC_LOG
+    BOOST_LOG_TRIVIAL(trace) << "[BELT-DEBUG] combined min_z=" << min_z
+        << " z_shift_val=" << z_shift_val;
+#endif
+    if (z_shift_val > 0.) {
+        Transform3d z_shift = Transform3d::Identity();
+        z_shift.matrix()(2, 3) = z_shift_val;
+        trafo = z_shift * trafo;
+    }
+    // out_belt_min_z is only meaningful in belt mode; the standalone-remap path
+    // never reported it.
+    if (out_belt_min_z && config.belt_printer.value) {
+        const double new_val = (min_z != std::numeric_limits<double>::max()) ? min_z : 0.;
+#ifdef SLIC3R_BELT_DIAGNOSTIC_LOG
+        BOOST_LOG_TRIVIAL(trace) << "[BELT-DEBUG] write m_belt_min_z tid=" << std::this_thread::get_id()
+            << " target=" << out_belt_min_z << " old=" << *out_belt_min_z << " new=" << new_val;
+#endif
+        *out_belt_min_z = new_val;
+    }
+#ifdef SLIC3R_BELT_DIAGNOSTIC_LOG
+    BOOST_LOG_TRIVIAL(trace) << "[BELT-DEBUG] apply_preslice_transforms exit"
+        << " final_trafo.linear=" << log_mat(trafo.linear())
+        << " final_trafo.translation=" << log_vec3(trafo.translation());
+#endif
+}
+
+} // namespace Slic3r

src/libslic3r/BeltSliceStrategy.hpp

@@ -0,0 +1,36 @@
+#pragma once
+
+#include "libslic3r.h"
+#include "Point.hpp"
+#include "BeltTransform.hpp"
+#include "PrintConfig.hpp"
+#include "Model.hpp"
+
+namespace Slic3r {
+
+// Belt printer / pre-slice transform strategy.
+//
+// Composes, in order, the pre-slice mesh transforms applied before slicing:
+//   1. Pre-slice axis remap (standalone — works without belt mode)
+//   2. Belt rotation (the sole mesh-side belt transform; shear & scale are a
+//      g-code-side stage, see MachineFrameTransform)
+//   3. Per-object Z-shift that lifts the mesh above the build plate
+//
+// Isolates this belt/remap-specific logic from the generic slicing pipeline in
+// PrintObjectSlice.cpp.
+class BeltSliceStrategy
+{
+public:
+    // Apply the pre-slice remap + belt rotation + Z-shift to `trafo` in place.
+    // No-op when neither a remap nor a belt rotation is configured.
+    //
+    // out_belt_min_z (if non-null) receives the minimum mesh Z after the
+    // transforms, but only in belt-printer mode — the standalone-remap path
+    // never reported it.
+    static void apply_preslice_transforms(Transform3d           &trafo,
+                                          const PrintConfig     &config,
+                                          const ModelVolumePtrs &model_volumes,
+                                          double                *out_belt_min_z = nullptr);
+};
+
+} // namespace Slic3r

src/libslic3r/BeltTransform.cpp

@@ -0,0 +1,223 @@
+#include "BeltTransform.hpp"
+#include "Model.hpp"
+
+#include <limits>
+
+namespace Slic3r {
+
+// ---- Matrix builders ------------------------------------------------------
+
+Transform3d BeltTransformPipeline::build_preslice_remap(const PrintConfig &config)
+{
+    Transform3d pre_remap = Transform3d::Identity();
+    if (!has_preslice_remap(config))
+        return pre_remap;
+
+    int pre_rx = int(config.preslice_remap_x.value);
+    int pre_ry = int(config.preslice_remap_y.value);
+    int pre_rz = int(config.preslice_remap_z.value);
+
+    // Each remap value selects a source axis and sign.
+    auto remap_column = [](int r) -> Vec3d {
+        int axis = r % 3;
+        Vec3d col = Vec3d::Zero();
+        if (r < 3)      col[axis] =  1.0;  // +axis
+        else if (r < 6) col[axis] = -1.0;  // -axis
+        else            col[axis] = -1.0;  // Rev: max - pos = -(pos - max)
+        return col;
+    };
+
+    Matrix3d remap_lin;
+    remap_lin.col(0) = remap_column(pre_rx);
+    remap_lin.col(1) = remap_column(pre_ry);
+    remap_lin.col(2) = remap_column(pre_rz);
+    pre_remap.linear() = remap_lin;
+
+    // Translation for Rev modes (needs build volume extents).
+    if (pre_rx >= 6 || pre_ry >= 6 || pre_rz >= 6) {
+        BoundingBoxf bbox_bed(config.printable_area.values);
+        Vec3d vol_max(bbox_bed.max.x(), bbox_bed.max.y(),
+                      config.printable_height.value);
+        Vec3d remap_trans = Vec3d::Zero();
+        auto add_rev = [&](int r, int out) {
+            if (r >= 6) remap_trans[out] = vol_max[r % 3];
+        };
+        add_rev(pre_rx, 0);
+        add_rev(pre_ry, 1);
+        add_rev(pre_rz, 2);
+        pre_remap.translation() = remap_trans;
+    }
+
+    return pre_remap;
+}
+
+Matrix3d BeltTransformPipeline::build_rotation_matrix(const PrintConfig &config, bool *has_rot_out)
+{
+    BeltRotationAxis axis = config.belt_slice_rotation.value;
+    double angle_deg = config.belt_slice_rotation_angle.value;
+    bool active = axis != BeltRotationAxis::None && std::abs(angle_deg) > EPSILON;
+    if (has_rot_out) *has_rot_out = active;
+    if (!active)
+        return Matrix3d::Identity();
+    double angle_rad = Geometry::deg2rad(angle_deg);
+    Vec3d unit_axis;
+    switch (axis) {
+    case BeltRotationAxis::X: unit_axis = Vec3d::UnitX(); break;
+    case BeltRotationAxis::Y: unit_axis = Vec3d::UnitY(); break;
+    case BeltRotationAxis::Z: unit_axis = Vec3d::UnitZ(); break;
+    default:                  return Matrix3d::Identity();
+    }
+    return Eigen::AngleAxisd(angle_rad, unit_axis).toRotationMatrix();
+}
+
+Transform3d BeltTransformPipeline::build_forward_transform(const PrintConfig &config)
+{
+    // Mesh-side belt transform: rotation applied after the pre-slice axis remap.
+    // (Shear & scale are a g-code-side stage, not part of the mesh transform.)
+    Transform3d pre_remap = build_preslice_remap(config);
+    Matrix3d    rot       = build_rotation_matrix(config);
+
+    Transform3d combined = Transform3d::Identity();
+    combined.linear() = rot;
+    combined = combined * pre_remap;
+    return combined;
+}
+
+// ---- Bounding box remap ---------------------------------------------------
+
+BoundingBoxf3 BeltTransformPipeline::remap_bbox(const BoundingBoxf3 &bb, const PrintConfig &config)
+{
+    int pre_rx = int(config.preslice_remap_x.value);
+    int pre_ry = int(config.preslice_remap_y.value);
+    int pre_rz = int(config.preslice_remap_z.value);
+
+    if (pre_rx == int(RemapAxis::PosX) &&
+        pre_ry == int(RemapAxis::PosY) &&
+        pre_rz == int(RemapAxis::PosZ))
+        return bb;  // Identity remap.
+
+    auto remap_coord = [](int r, const Vec3d &v) -> double {
+        int axis = r % 3;
+        if (r < 3) return v[axis];
+        return -v[axis];
+    };
+
+    Vec3d mn = bb.min.cast<double>(), mx = bb.max.cast<double>();
+    BoundingBoxf3 rbb;
+    for (int i = 0; i < 8; ++i) {
+        Vec3d c((i & 1) ? mx.x() : mn.x(),
+                (i & 2) ? mx.y() : mn.y(),
+                (i & 4) ? mx.z() : mn.z());
+        Vec3d rc(remap_coord(pre_rx, c), remap_coord(pre_ry, c), remap_coord(pre_rz, c));
+        if (i == 0) rbb = BoundingBoxf3(rc, rc);
+        else rbb.merge(rc);
+    }
+    return rbb;
+}
+
+BoundingBoxf3 BeltTransformPipeline::remap_bbox(const ModelObject &model_object, const PrintConfig &config)
+{
+    return remap_bbox(model_object.raw_bounding_box(), config);
+}
+
+// ---- Belt floor parameters ------------------------------------------------
+
+// Shared implementation for both PrintConfig and DynamicPrintConfig.
+// Template avoids duplicating the math for the two config types.
+namespace {
+
+template<typename Config>
+BeltTransformPipeline::BeltHeightResult compute_belt_height_and_floor_impl(
+    const Config &config, const BoundingBoxf3 &bb, double original_height)
+{
+    BeltTransformPipeline::BeltHeightResult result;
+    result.object_height = original_height;
+
+    // Extract the mesh rotation from config (the sole mesh-side belt transform).
+    BeltRotationAxis rot_axis;
+    double           rot_angle;
+
+    if constexpr (std::is_same_v<Config, PrintConfig>) {
+        rot_axis  = config.belt_slice_rotation.value;
+        rot_angle = config.belt_slice_rotation_angle.value;
+    } else {
+        // DynamicPrintConfig path
+        auto get_float = [&](const char *key) {
+            auto *opt = config.template option<ConfigOptionFloat>(key);
+            return opt ? opt->value : 0.0;
+        };
+        auto get_rot_axis = [&](const char *key) {
+            auto *opt = config.template option<ConfigOptionEnum<BeltRotationAxis>>(key);
+            return opt ? opt->value : BeltRotationAxis::None;
+        };
+        rot_axis  = get_rot_axis("belt_slice_rotation");
+        rot_angle = get_float("belt_slice_rotation_angle");
+    }
+
+    bool has_rotation = rot_axis != BeltRotationAxis::None && std::abs(rot_angle) > EPSILON;
+    if (!has_rotation)
+        return result;
+
+    // Rotation path: sweep the 8 bbox corners through R to get the rotated height,
+    // then derive the belt floor (the image of machine-Z = 0 under R).
+    double angle_rad = Geometry::deg2rad(rot_angle);
+    Vec3d unit_axis;
+    switch (rot_axis) {
+    case BeltRotationAxis::X: unit_axis = Vec3d::UnitX(); break;
+    case BeltRotationAxis::Y: unit_axis = Vec3d::UnitY(); break;
+    case BeltRotationAxis::Z: unit_axis = Vec3d::UnitZ(); break;
+    default:                  unit_axis = Vec3d::UnitX(); break;
+    }
+    Matrix3d R = Eigen::AngleAxisd(angle_rad, unit_axis).toRotationMatrix();
+    double min_rz = std::numeric_limits<double>::max();
+    double max_rz = std::numeric_limits<double>::lowest();
+    for (int i = 0; i < 8; ++i) {
+        Vec3d c((i & 1) ? bb.max.x() : bb.min.x(),
+                (i & 2) ? bb.max.y() : bb.min.y(),
+                (i & 4) ? bb.max.z() : bb.min.z());
+        double z = (R * c).z();
+        min_rz = std::min(min_rz, z);
+        max_rz = std::max(max_rz, z);
+    }
+    result.object_height = max_rz - min_rz;
+
+    // Belt floor in slicer-frame is the image of z_machine = 0 under R.
+    //   R(+α, X): point (·, y, 0) → (·, cos α · y, sin α · y) ⇒ z = tan(α) · y_s
+    //   R(+α, Y): point (x, ·, 0) → (cos α · x, ·, -sin α · x) ⇒ z = -tan(α) · x_s
+    //   R(+α, Z): point (·, ·, 0) → (·, ·, 0); no tilt → no floor
+    double sin_a = std::sin(angle_rad), cos_a = std::cos(angle_rad);
+    switch (rot_axis) {
+    case BeltRotationAxis::X:
+        result.floor_params.shear_factor = (std::abs(cos_a) > EPSILON) ?  sin_a / cos_a : 0.;
+        result.floor_params.from_axis    = 1; // Y
+        break;
+    case BeltRotationAxis::Y:
+        result.floor_params.shear_factor = (std::abs(cos_a) > EPSILON) ? -sin_a / cos_a : 0.;
+        result.floor_params.from_axis    = 0; // X
+        break;
+    case BeltRotationAxis::Z:
+    default:
+        result.floor_params.shear_factor = 0.0;
+        result.floor_params.from_axis    = 1;
+        break;
+    }
+    result.floor_params.z_shift = bb.min.z() + ((min_rz < 0.) ? -min_rz : 0.);
+
+    return result;
+}
+
+} // anonymous namespace
+
+BeltTransformPipeline::BeltHeightResult BeltTransformPipeline::compute_belt_height_and_floor(
+    const PrintConfig &config, const BoundingBoxf3 &remapped_bbox, double original_height)
+{
+    return compute_belt_height_and_floor_impl(config, remapped_bbox, original_height);
+}
+
+BeltTransformPipeline::BeltHeightResult BeltTransformPipeline::compute_belt_height_and_floor(
+    const DynamicPrintConfig &config, const BoundingBoxf3 &remapped_bbox, double original_height)
+{
+    return compute_belt_height_and_floor_impl(config, remapped_bbox, original_height);
+}
+
+} // namespace Slic3r

src/libslic3r/BeltTransform.hpp

@@ -0,0 +1,152 @@
+#pragma once
+
+#include "libslic3r.h"
+#include "Point.hpp"
+#include "BoundingBox.hpp"
+#include "PrintConfig.hpp"
+#include "Geometry.hpp"
+
+#include <cmath>
+
+namespace Slic3r {
+
+class ModelObject;
+
+// Shared belt-printer transform math.
+//
+// The pre-slice pipeline applied in PrintObjectSlice.cpp is:
+//     trafo_out = z_shift * rotation * pre_remap * trafo_in
+//
+// Rotation is the sole mesh-side belt transform; shear & scale are applied
+// to the g-code instead (see MachineFrameTransform).  This class provides the
+// building blocks so every call site uses the same implementation.  z_shift is
+// object-dependent (computed from mesh vertex bounds) and is NOT included in
+// build_forward_transform().  The machine-frame shear/scale is derived directly
+// from the tilt angle in MachineFrameTransform and no longer lives here.
+//
+// Design note: this mesh-rotation approach replaced an earlier pre-shear
+// method (now removed).  While that initial pre-shear method was instrumental
+// in getting belt printer slicing off the ground in the first place, its place is
+// in the past.  A big thank you goes to the Unlayered3D team, who recommended 
+// switching to a pre-slice rotation stage instead.  Doing so keeps the slicing 
+// operation isometric — no distortion of the sliced geometry — while the 
+// non-orthogonal machine-axis compensation is confined to a g-code-side shear/scale
+// derived from the same tilt angle.
+// 
+// This fixed a number of issues, including several issues noticed by hotcubcar
+// regarding adaptive infills not working, gyroid becoming anisotropic, and more 
+// that were all mostly resolved as a result of the switch.
+// 
+// This also means that the pre-slice rotation transform methodology can be used 
+// more cleanly on non-belt printers.
+// - HarrierPigeon (Joseph Robertson)
+
+class BeltTransformPipeline
+{
+public:
+    // ---- Identity checks --------------------------------------------------
+
+    static bool has_preslice_remap(const PrintConfig &config)
+    {
+        return int(config.preslice_remap_x.value) != int(RemapAxis::PosX) ||
+               int(config.preslice_remap_y.value) != int(RemapAxis::PosY) ||
+               int(config.preslice_remap_z.value) != int(RemapAxis::PosZ);
+    }
+
+    // Overload accepting DynamicPrintConfig (used in static slicing_parameters).
+    static bool has_preslice_remap(const DynamicPrintConfig &config)
+    {
+        auto get_int = [&](const char *key) -> int {
+            auto *opt = config.option<ConfigOptionEnum<RemapAxis>>(key);
+            return opt ? int(opt->value) : 0;
+        };
+        return get_int("preslice_remap_x") != int(RemapAxis::PosX) ||
+               get_int("preslice_remap_y") != int(RemapAxis::PosY) ||
+               get_int("preslice_remap_z") != int(RemapAxis::PosZ);
+    }
+
+    static bool has_rotation(const PrintConfig &config)
+    {
+        return config.belt_slice_rotation.value != BeltRotationAxis::None &&
+               std::abs(config.belt_slice_rotation_angle.value) > EPSILON;
+    }
+
+    // Physical belt tilt derived from the slicing rotation — the single source of
+    // truth for bed rendering, support gravity tilt and the bed-exclusion
+    // projection.  Returns the tilt magnitude in degrees split onto the X and Y
+    // build-plate tilt axes according to the rotation axis:
+    //   rotation about X  → tilt_x = angle   (gantry tilts in the YZ plane)
+    //   rotation about Y  → tilt_y = angle   (gantry tilts in the XZ plane)
+    //   rotation about Z / None → no tilt    (in-plane spin doesn't tilt the belt)
+    // The magnitude uses abs(angle) so a negative rotation still reports a positive
+    // physical tilt.
+    struct PhysicalTilt { double tilt_x_deg = 0.; double tilt_y_deg = 0.; };
+
+    static PhysicalTilt physical_tilt(BeltRotationAxis axis, double angle_deg)
+    {
+        PhysicalTilt t;
+        double mag = std::abs(angle_deg);
+        switch (axis) {
+        case BeltRotationAxis::X: t.tilt_x_deg = mag; break;
+        case BeltRotationAxis::Y: t.tilt_y_deg = mag; break;
+        default: break; // Z / None: no physical tilt
+        }
+        return t;
+    }
+
+    static PhysicalTilt physical_tilt(const PrintConfig &config)
+    {
+        return physical_tilt(config.belt_slice_rotation.value,
+                             config.belt_slice_rotation_angle.value);
+    }
+
+    // ---- Matrix builders --------------------------------------------------
+
+    // Build the pre-slice axis remap transform (includes Rev-mode translation).
+    static Transform3d build_preslice_remap(const PrintConfig &config);
+
+    // Build the 3x3 rotation matrix from belt_slice_rotation* config.
+    // Returns Identity if rotation axis is None or angle is ~0.
+    // Also sets has_rot_out if non-null.
+    static Matrix3d build_rotation_matrix(const PrintConfig &config, bool *has_rot_out = nullptr);
+
+    // Combined forward transform (rotation * pre_remap) — the mesh-side belt
+    // transform that BeltSliceStrategy applies and BeltBackTransform inverts.
+    // Does NOT include the per-object Z-shift.
+    static Transform3d build_forward_transform(const PrintConfig &config);
+
+    // ---- Bounding box remap -----------------------------------------------
+
+    // Remap a bounding box through the pre-slice axis remap.
+    // Returns the original bbox if remap is identity.
+    static BoundingBoxf3 remap_bbox(const BoundingBoxf3 &bb, const PrintConfig &config);
+    static BoundingBoxf3 remap_bbox(const ModelObject &model_object, const PrintConfig &config);
+
+    // ---- Belt floor parameters --------------------------------------------
+
+    struct BeltFloorParams {
+        double shear_factor = 0.0;
+        int    from_axis    = 1;
+        double z_shift      = 0.0;
+    };
+
+    // Result of computing belt height + floor params.
+    struct BeltHeightResult {
+        double          object_height;  // Effective object height after shear/scale
+        BeltFloorParams floor_params;
+    };
+
+    // Compute effective object height and belt floor parameters from config
+    // and pre-remapped bounding box.  original_height is the input height
+    // (bb.size().z() or model_object.max_z()).
+    static BeltHeightResult compute_belt_height_and_floor(
+        const PrintConfig &config, const BoundingBoxf3 &remapped_bbox,
+        double original_height);
+
+    // Overload for DynamicPrintConfig (used by static slicing_parameters).
+    static BeltHeightResult compute_belt_height_and_floor(
+        const DynamicPrintConfig &config, const BoundingBoxf3 &remapped_bbox,
+        double original_height);
+};
+
+} // namespace Slic3r

src/libslic3r/Brim.cpp

@@ -449,7 +449,9 @@ static ExPolygons outer_inner_brim_area(const Print& print,
             const bool         use_brim_ears = object->config().brim_type == btPainted;
             const bool         use_inner_brim_ears = (use_auto_brim_ears || use_brim_ears) && !object->config().brim_ears_outer_only.value;
             const bool         has_inner_brim = brim_type == btInnerOnly || brim_type == btOuterAndInner || use_inner_brim_ears;
-            const bool         has_outer_brim = brim_type == btOuterOnly || brim_type == btOuterAndInner || brim_type == btAutoBrim || use_auto_brim_ears || use_brim_ears;
+            // btLeadingEdgeOnly is a belt-printer mode; on a flat bed there is no leading
+            // edge, so it degrades to an ordinary outer brim rather than silently to none.
+            const bool         has_outer_brim = brim_type == btOuterOnly || brim_type == btOuterAndInner || brim_type == btAutoBrim || brim_type == btLeadingEdgeOnly || use_auto_brim_ears || use_brim_ears;
             coord_t            ear_detection_length = scale_(object->config().brim_ears_detection_length.value);
             coordf_t           brim_ears_max_angle = object->config().brim_ears_max_angle.value;
             //ORCA: Select brim base slices from EFC-compensated outline when enabled.
@@ -864,6 +866,17 @@ void make_brim(const Print& print, PrintTryCancel try_cancel, Polygons& islands_
     std::vector<unsigned int>& printExtruders,
     std::map<ObjectInstanceID, ExPolygons>* objectBrimAreasByInstanceOut)
 {
+    // Belt printers never use the flat plate brim.
+    //
+    // With a tilted belt the brim has to be laid onto the belt plane over many layers,
+    // which BeltBrim.cpp does during posSupportMaterial.  With an untilted belt this
+    // could in principle fall through and produce an ordinary brim, but it would never
+    // reach the G-code: the plate brim is emitted out of skirt_brim_groups(), which
+    // _make_skirt() builds, and that returns early for every belt printer.  Running the
+    // generator anyway would just burn time on geometry nobody prints.
+    if (print.config().belt_printer.value)
+        return;
+
     std::map<ObjectInstanceID, ExPolygons> brimAreaMap;
     Flow                 flow = print.brim_flow();
     ExPolygons           islands_area_ex = outer_inner_brim_area(print,

src/libslic3r/BuildVolume.cpp

@@ -180,6 +180,31 @@ BuildVolume::BuildVolume(const std::vector<Vec2d> &printable_area, const double
     BOOST_LOG_TRIVIAL(debug) << "BuildVolume printable_area clasified as: " << this->type_name();
 }
 
+void BuildVolume::set_belt_printer(bool enabled, double angle_deg, bool infinite_y)
+{
+    m_is_belt_printer = enabled;
+    m_belt_angle = angle_deg;
+    m_belt_infinite_y = infinite_y;
+
+    // Restart from the unmodified bbox each call. Without this, toggling
+    // belt mode off (or switching infinite_y true→false) would leave the
+    // extents inflated and break collision / object_state checks.
+    BoundingBoxf bboxf = get_extents(m_bed_shape);
+    m_bboxf = BoundingBoxf3{ to_3d(bboxf.min, 0.), to_3d(bboxf.max, m_max_print_height) };
+
+    if (enabled) {
+        if (infinite_y) {
+            // Extend the Y bound to a very large value for infinite belt.
+            m_bboxf.max.y() = 100000.;
+        }
+        // Belt printer: the Z extent already equals printable_height (set above), which
+        // is the usable vertical clearance above the belt. The gantry's axis range is
+        // sized to reach height/cos(tilt), so no diagonal scaling is applied here — this
+        // keeps the live "outside build volume" highlight in agreement with Print::validate().
+        (void) angle_deg;
+    }
+}
+
 #if 0
 // Tests intersections of projected triangles, not just their vertices against a bounding box.
 // This test also correctly evaluates collision of a non-convex object with the bounding box.
@@ -388,6 +413,11 @@ BuildVolume::ObjectState BuildVolume::object_state(const indexed_triangle_set& i
             build_volume.max.z() = std::numeric_limits<double>::max();
         if (ignore_bottom)
             build_volume.min.z() = -std::numeric_limits<double>::max();
+        // Belt printer: extend Y bounds for infinite Y.
+        if (m_is_belt_printer && m_belt_infinite_y) {
+            build_volume.min.y() = -std::numeric_limits<double>::max();
+            build_volume.max.y() = std::numeric_limits<double>::max();
+        }
         BoundingBox3Base<Vec3f> build_volumef(build_volume.min.cast<float>(), build_volume.max.cast<float>());
         // The following test correctly interprets intersection of a non-convex object with a rectangular build volume.
         //return rectangle_test(its, trafo, to_2d(build_volume.min), to_2d(build_volume.max), build_volume.max.z());

src/libslic3r/BuildVolume.hpp

@@ -57,6 +57,10 @@ public:
     // Initialize from PrintConfig::printable_area and PrintConfig::printable_height
     BuildVolume(const std::vector<Vec2d> &printable_area, const double printable_height, const std::vector<std::vector<Vec2d>> &extruder_areas, const std::vector<double>& extruder_printable_heights);
 
+    // Belt printer configuration.
+    void set_belt_printer(bool enabled, double angle_deg, bool infinite_y);
+    bool is_belt_printer() const { return m_is_belt_printer; }
+
     // Source data, unscaled coordinates.
     const std::vector<Vec2d>&   printable_area()         const { return m_bed_shape; }
     double                      printable_height()  const { return m_max_print_height; }
@@ -80,7 +84,7 @@ public:
     indexed_triangle_set        bounding_mesh(bool scale=true) const;
 
     // Center of the print bed, unscaled.
-    Vec2d                       bed_center()        const { return to_2d(m_bboxf.center()); }
+    Vec2d                       bed_center()        const { return get_extents(m_bed_shape).center(); }
     // Convex hull of polygon(), scaled.
     const Polygon&              convex_hull()       const { return m_convex_hull; }
     // Smallest enclosing circle of polygon(), scaled.
@@ -139,6 +143,10 @@ private:
     // Source definition of the print volume height (PrintConfig::printable_height)
     double              m_max_print_height { 0.f };
     std::vector<double> m_extruder_printable_height;
+    // Belt printer state.
+    bool                m_is_belt_printer { false };
+    double              m_belt_angle { 0. };
+    bool                m_belt_infinite_y { false };
 
     // Derived values.
     BuildVolume_Type                m_type { BuildVolume_Type::Invalid };

src/libslic3r/CMakeLists.txt

@@ -80,6 +80,19 @@ set(lisbslic3r_sources
     BoundingBox.hpp
     BridgeDetector.cpp
     BridgeDetector.hpp
+    BeltBrim.cpp
+    BeltBrim.hpp
+    BeltGCode.cpp
+    BeltGCode.hpp
+    BeltGCodeWriter.cpp
+    BeltGCodeWriter.hpp
+    BeltPurge.cpp
+    BeltSliceStrategy.cpp
+    BeltSliceStrategy.hpp
+    BeltTransform.cpp
+    BeltTransform.hpp
+    FirstLayerPlane.cpp
+    FirstLayerPlane.hpp
     Brim.cpp
     BrimEarsPoint.hpp
     Brim.hpp
@@ -228,6 +241,10 @@ set(lisbslic3r_sources
     GCode/AdaptivePAProcessor.hpp
     GCode/AvoidCrossingPerimeters.cpp
     GCode/AvoidCrossingPerimeters.hpp
+    GCode/BeltBackTransform.cpp
+    GCode/BeltBackTransform.hpp
+    GCode/MachineFrameTransform.cpp
+    GCode/MachineFrameTransform.hpp
     GCode/ConflictChecker.cpp
     GCode/ConflictChecker.hpp
     GCode/CoolingBuffer.cpp
@@ -442,6 +459,8 @@ set(lisbslic3r_sources
     SlicingAdaptive.hpp
     Slicing.cpp
     Slicing.hpp
+    Support/BeltFloorContext.cpp
+    Support/BeltFloorContext.hpp
     Support/SupportCommon.cpp
     Support/SupportCommon.hpp
     Support/SupportLayer.hpp

src/libslic3r/ExPolygon.hpp

@@ -396,6 +396,11 @@ inline void translate(ExPolygons &expolys, const Point &p) {
         expoly.translate(p);
 }
 
+inline void translate(Polygons &polys, const Point &p) {
+    for (Polygon &poly : polys)
+        poly.translate(p);
+}
+
 inline void polygons_append(Polygons &dst, const ExPolygon &src) 
 { 
     dst.reserve(dst.size() + src.holes.size() + 1);

src/libslic3r/FirstLayerPlane.cpp

@@ -0,0 +1,225 @@
+#include "FirstLayerPlane.hpp"
+#include "BeltTransform.hpp"
+
+#include <algorithm>
+#include <climits>
+#include <cmath>
+
+namespace Slic3r {
+
+namespace {
+
+// Build the row of the gcode-axis-remap matrix R that produces machine_Z,
+// AS A FUNCTION OF a slicing-frame point in the GCode generator's coordinate
+// space.  Without back-transform this is just R.row(2).  With back-transform
+// the writer applies F^-1 before R, so the effective row is (R * F^-1).row(2).
+//
+// Returns a pair (gradient, constant) such that:
+//     machine_Z(p_slicing) = gradient.dot(p_slicing) + constant
+struct MachineZAffine {
+    Vec3d  gradient = Vec3d::UnitZ();
+    double constant = 0.0;
+};
+
+MachineZAffine compute_machine_z_affine(const PrintConfig &config)
+{
+    MachineZAffine out;
+
+    // R is the matrix form of GCodeWriter::apply_axis_remap.  Each output axis
+    // i picks one slicing-frame component (with sign + optional Rev mode
+    // translation) based on m_remap_{x,y,z}.  We only need row 2 (the z output)
+    // since machine_Z is what defines the first-layer plane.
+    int rz = int(config.gcode_remap_z.value);
+    int axis = rz % 3;
+    double sign;
+    double trans;
+    if (rz < int(RemapAxis::NegX)) {            // 0..2 = PosX/Y/Z
+        sign  = 1.0;
+        trans = 0.0;
+    } else if (rz < int(RemapAxis::RevX)) {     // 3..5 = NegX/Y/Z
+        sign  = -1.0;
+        trans = 0.0;
+    } else {                                     // 6..8 = RevX/Y/Z
+        sign = -1.0;
+        BoundingBoxf bbox_bed(config.printable_area.values);
+        Vec3d vol_max(bbox_bed.max.x(),
+                      bbox_bed.max.y(),
+                      config.printable_height.value);
+        trans = vol_max[axis];
+    }
+
+    Vec3d r_row = Vec3d::Zero();
+    r_row[axis] = sign;
+
+    // Without back-transform, machine_Z(slicing) = r_row · slicing + trans.
+    out.gradient = r_row;
+    out.constant = trans;
+
+    if (config.gcode_back_transform.value && config.belt_printer.value) {
+        // BeltGCodeWriter applies F^-1 before R when back-transform is on.
+        // So machine_Z(slicing) = r_row · (F^-1 · slicing) + trans
+        //                       = (r_row^T · F^-1) · slicing + trans
+        // We need to compose r_row with F^-1 from the LEFT (treating r_row as
+        // a row vector).  Eigen makes this easy: it's just F^-1.transpose() * r_row.
+        Transform3d forward = BeltTransformPipeline::build_forward_transform(config);
+        Transform3d inverse = forward.inverse();
+        // Note: forward.translation() is normally zero (per-print transforms
+        // don't add a translation; the per-object z_shift is added separately
+        // in PrintObjectSlice).  We still incorporate inverse.translation() in
+        // case a Rev-mode preslice_remap puts a translation in F.
+        Vec3d composed_grad = inverse.linear().transpose() * r_row;
+        double composed_trans =
+            r_row.dot(inverse.translation()) + trans;
+        out.gradient = composed_grad;
+        out.constant = composed_trans;
+    }
+
+    return out;
+}
+
+} // namespace
+
+FirstLayerPlane::FirstLayerPlane(const PrintConfig &config)
+{
+    // -------- Resolve Auto -------------------------------------------------
+    FirstLayerPlaneMode mode = config.first_layer_plane.value;
+    if (mode == FirstLayerPlaneMode::Auto) {
+        bool belt_affine_active = config.belt_printer.value &&
+            config.belt_slice_rotation.value != BeltRotationAxis::None &&
+            std::abs(config.belt_slice_rotation_angle.value) > EPSILON;
+        mode = belt_affine_active ? FirstLayerPlaneMode::BeltAffine
+                                  : FirstLayerPlaneMode::XY;
+    }
+    m_mode = mode;
+
+    // -------- Band thickness ----------------------------------------------
+    // Note: layer_height lives in PrintObjectConfig, not PrintConfig, so we
+    // can't fall back to it from here.  initial_layer_print_height is in
+    // PrintConfig and is the right default anyway (the legacy first-layer
+    // semantics used initial_layer_print_height, not the regular one).
+    double thickness = config.first_layer_plane_thickness.value;
+    if (thickness <= 0.0)
+        thickness = config.initial_layer_print_height.value;
+    if (thickness <= 0.0)
+        thickness = 0.2;
+    m_thickness_mm = thickness;
+
+    const double user_offset = config.first_layer_plane_offset.value;
+
+    // -------- Build the plane ---------------------------------------------
+    auto set_axis_aligned = [&](const Vec3d &n_unit, double offset_along_n) {
+        m_normal = n_unit;
+        m_offset = offset_along_n;
+    };
+
+    switch (mode) {
+    case FirstLayerPlaneMode::XY:
+        // Legacy XY plane.  Inactive: short-circuit to layer-index path.
+        set_axis_aligned(Vec3d::UnitZ(), user_offset);
+        m_active = false;
+        return;
+
+    case FirstLayerPlaneMode::YZ:
+        set_axis_aligned(Vec3d::UnitX(), user_offset);
+        m_active = true;
+        return;
+
+    case FirstLayerPlaneMode::XZ:
+        set_axis_aligned(Vec3d::UnitY(), user_offset);
+        m_active = true;
+        return;
+
+    case FirstLayerPlaneMode::BeltAffine: {
+        // Compute the slicing-frame plane that maps to machine_Z = user_offset
+        // under the gcode axis remap (and optional back-transform).
+        MachineZAffine mz = compute_machine_z_affine(config);
+        double cmag = mz.gradient.norm();
+        if (cmag < EPSILON) {
+            // Degenerate: slicing point doesn't affect machine_Z.  Fall back.
+            set_axis_aligned(Vec3d::UnitZ(), user_offset);
+            m_active = false;
+            return;
+        }
+        // Plane equation: gradient · slicing = user_offset - constant
+        const double K = user_offset - mz.constant;
+        m_normal = mz.gradient / cmag;
+        m_offset = K / cmag;
+        m_active = true;
+        return;
+    }
+
+    case FirstLayerPlaneMode::Auto:
+        // Should have been resolved above.
+        m_active = false;
+        return;
+    }
+
+    m_active = false;
+}
+
+double FirstLayerPlane::distance_from_plane(const Vec3d &point_slicing_mm) const
+{
+    return m_normal.dot(point_slicing_mm) - m_offset;
+}
+
+bool FirstLayerPlane::is_first_layer(const Vec3d &point_slicing_mm,
+                                     double first_layer_height_mm) const
+{
+    if (!m_active)
+        return false;
+    return distance_from_plane(point_slicing_mm) < first_layer_height_mm;
+}
+
+int FirstLayerPlane::effective_layer_index(const Vec3d &point_slicing_mm) const
+{
+    if (!m_active)
+        return INT_MAX / 2;  // Effectively "way past first layer".
+    double d = distance_from_plane(point_slicing_mm);
+    if (d <= 0.0)
+        return 0;
+    return int(std::floor(d / m_thickness_mm));
+}
+
+int FirstLayerPlane::min_effective_index_for_xy_bbox(
+    const BoundingBoxf &xy_bbox_mm, double slicing_z_mm) const
+{
+    if (!m_active)
+        return INT_MAX / 2;
+    // For the rectangular bbox in (x, y) at fixed z, the smallest value of
+    // (n.x*x + n.y*y + n.z*z - offset) is achieved at one of the four
+    // corners, with the smaller component picked when the corresponding
+    // normal coefficient is positive.
+    const double x_for_min = (m_normal.x() >= 0.0)
+        ? xy_bbox_mm.min.x() : xy_bbox_mm.max.x();
+    const double y_for_min = (m_normal.y() >= 0.0)
+        ? xy_bbox_mm.min.y() : xy_bbox_mm.max.y();
+    const double dmin = m_normal.x() * x_for_min
+                      + m_normal.y() * y_for_min
+                      + m_normal.z() * slicing_z_mm
+                      - m_offset;
+    if (dmin <= 0.0)
+        return 0;
+    return int(std::floor(dmin / m_thickness_mm));
+}
+
+int FirstLayerPlane::min_effective_index_for_bbox3(
+    const BoundingBoxf3 &bbox_mm) const
+{
+    if (!m_active)
+        return INT_MAX / 2;
+    const double x_for_min = (m_normal.x() >= 0.0)
+        ? bbox_mm.min.x() : bbox_mm.max.x();
+    const double y_for_min = (m_normal.y() >= 0.0)
+        ? bbox_mm.min.y() : bbox_mm.max.y();
+    const double z_for_min = (m_normal.z() >= 0.0)
+        ? bbox_mm.min.z() : bbox_mm.max.z();
+    const double dmin = m_normal.x() * x_for_min
+                      + m_normal.y() * y_for_min
+                      + m_normal.z() * z_for_min
+                      - m_offset;
+    if (dmin <= 0.0)
+        return 0;
+    return int(std::floor(dmin / m_thickness_mm));
+}
+
+} // namespace Slic3r

src/libslic3r/FirstLayerPlane.hpp

@@ -0,0 +1,76 @@
+#ifndef slic3r_FirstLayerPlane_hpp_
+#define slic3r_FirstLayerPlane_hpp_
+
+#include "libslic3r.h"
+#include "Point.hpp"
+#include "BoundingBox.hpp"
+#include "PrintConfig.hpp"
+
+namespace Slic3r {
+
+// Decides which extrusions get "first layer" treatment (no fan, slow speed,
+// initial-layer accel/jerk, deferred temperature drop) by reference to a
+// configurable plane in slicing-frame coordinates rather than the slicing
+// layer index.
+//
+// On a normal flat-bed printer the plane is XY at slicing_Z = 0 and the
+// evaluator is INACTIVE — every call site short-circuits back to the legacy
+// `Layer::id() == 0` test.  On a belt printer with a Z-from-Y shear the
+// belt surface (machine_Z = 0) maps to a plane in slicing-frame coordinates
+// derived from the gcode axis remap, so layer-index-based detection no
+// longer matches the physical first printed surface.
+//
+// Plane representation: unit normal `n` (slicing frame) and offset along
+// the normal such that the plane equation is `n · p == offset`.  Signed
+// perpendicular distance is `d(p) = n · p - offset`.  Positive distance
+// means "away from the belt surface", negative means "below the plane".
+class FirstLayerPlane
+{
+public:
+    explicit FirstLayerPlane(const PrintConfig &config);
+
+    // Inactive when the legacy XY layer-index path should be used.  This
+    // covers all non-belt printers and any belt printer where the user
+    // explicitly picked XY mode.
+    bool                is_active() const     { return m_active; }
+    FirstLayerPlaneMode effective_mode() const{ return m_mode; }
+    double              band_thickness_mm() const { return m_thickness_mm; }
+    const Vec3d &       normal() const        { return m_normal; }
+    double              plane_offset() const  { return m_offset; }
+
+    // Signed perpendicular distance from a slicing-frame point to the plane.
+    double distance_from_plane(const Vec3d &point_slicing_mm) const;
+
+    // True if perpendicular distance < first_layer_height_mm.  When the
+    // evaluator is inactive this returns false (call sites should fall back
+    // to the legacy per-layer path before reaching this function).
+    bool is_first_layer(const Vec3d &point_slicing_mm,
+                        double first_layer_height_mm) const;
+
+    // floor((distance - 0) / band_thickness), clamped to [0, +inf).  Used
+    // for "first N layers" thresholds (fan, slow_down_layers).  Returns 0
+    // for points within the band.  Returns INT_MAX/2 when inactive.
+    int effective_layer_index(const Vec3d &point_slicing_mm) const;
+
+    // Min effective index over a 2D bbox at a fixed slicing_Z.  Used for
+    // layer-level decisions (e.g. temperature transition gate) where we
+    // don't want to walk every extrusion in the layer.  For axis-aligned
+    // planes this is exact; for tilted planes it's a tight lower bound
+    // (the plane projection of the bbox's extreme corner).
+    int min_effective_index_for_xy_bbox(const BoundingBoxf &xy_bbox_mm,
+                                        double              slicing_z_mm) const;
+
+    // Same as above but the bbox spans a Z range too.
+    int min_effective_index_for_bbox3(const BoundingBoxf3 &bbox_mm) const;
+
+private:
+    bool                m_active        = false;
+    FirstLayerPlaneMode m_mode          = FirstLayerPlaneMode::XY;
+    Vec3d               m_normal        = Vec3d::UnitZ();  // unit, slicing frame
+    double              m_offset        = 0.0;             // n·p == m_offset
+    double              m_thickness_mm  = 0.0;
+};
+
+} // namespace Slic3r
+
+#endif // slic3r_FirstLayerPlane_hpp_

src/libslic3r/GCode.hpp

@@ -4,6 +4,8 @@
 #include "libslic3r.h"
 #include "ExPolygon.hpp"
 #include "GCodeWriter.hpp"
+#include "BeltGCodeWriter.hpp"
+#include "FirstLayerPlane.hpp"
 #include "Layer.hpp"
 #include "Point.hpp"
 #include "PlaceholderParser.hpp"
@@ -31,6 +33,7 @@
 
 #include <memory>
 #include <map>
+#include <optional>
 #include <set>
 #include <string>
 #include <cfloat>
@@ -214,16 +217,18 @@ public:
         m_last_obj_copy(nullptr, Point(std::numeric_limits<coord_t>::max(), std::numeric_limits<coord_t>::max())),
         // BBS
         m_toolchange_count(0),
-        m_nominal_z(0.)
+        m_nominal_z(0.),
+        m_writer(std::make_unique<GCodeWriter>())
         {}
-    ~GCode() = default;
+    virtual ~GCode() = default;
 
+public:
     // throws std::runtime_exception on error,
     // throws CanceledException through print->throw_if_canceled().
     void            do_export(Print* print, const char* path, GCodeProcessorResult* result = nullptr, ThumbnailsGeneratorCallback thumbnail_cb = nullptr);
     void            export_layer_filaments(GCodeProcessorResult* result);
     //BBS: set offset for gcode writer
-    void set_gcode_offset(double x, double y) { m_writer.set_xy_offset(x, y); m_processor.set_xy_offset(x, y);}
+    void set_gcode_offset(double x, double y) { m_writer->set_xy_offset(x, y); m_processor.set_xy_offset(x, y);}
 
     // Exported for the helper classes (OozePrevention, Wipe) and for the Perl binding for unit tests.
     const Vec2d&    origin() const { return m_origin; }
@@ -237,8 +242,8 @@ public:
     Vec3d                    point_to_gcode_quantized(const Point3& point) const;
     const FullPrintConfig &config() const { return m_config; }
     const Layer*    layer() const { return m_layer; }
-    GCodeWriter&    writer() { return m_writer; }
+    GCodeWriter&    writer() { return *m_writer; }
-    const GCodeWriter& writer() const { return m_writer; }
+    const GCodeWriter& writer() const { return *m_writer; }
     PlaceholderParser& placeholder_parser() { return m_placeholder_parser_integration.parser; }
     const PlaceholderParser& placeholder_parser() const { return m_placeholder_parser_integration.parser; }
     // Process a template through the placeholder parser, collect error messages to be reported
@@ -261,7 +266,7 @@ public:
     bool            needs_retraction(const Polyline& travel, ExtrusionRole role, LiftType& lift_type);
     std::string     retract(bool toolchange = false, bool is_last_retraction = false, LiftType lift_type = LiftType::NormalLift, bool apply_instantly = false, ExtrusionRole role = erNone);
     // extra_retract forwards a PETG pre-extrusion over-extrusion; default 0 -> identical to the plain deretract.
-    std::string     unretract(float extra_retract = 0.f) { return m_writer.unlift() + m_writer.unretract(extra_retract); }
+    std::string     unretract(float extra_retract = 0.f) { return m_writer->unlift() + m_writer->unretract(extra_retract); }
     std::string     set_extruder(unsigned int extruder_id, double print_z, bool by_object=false, int toolchange_temp_override = -1, bool defer_temp_wait = false);
     bool is_BBL_Printer();
     WipeTowerType wipe_tower_type();
@@ -286,6 +291,13 @@ public:
         const Layer* 		object_layer;
         const SupportLayer* support_layer;
         const PrintObject*  original_object; //BBS: used for shared object logic
+        // Belt printers only: an apron band that prints BELOW the object's first
+        // layer, so it has no object or support layer of its own.  Deliberately
+        // not a Layer, so it cannot leak Layer::id() semantics into initial-layer
+        // temperature, spiral vase, cooling or interpolation logic.  When this is
+        // the only thing set, layer() is null and process_layer() takes its
+        // dedicated brim-only branch.
+        const BeltBrimBand* belt_brim_band { nullptr };
         const Layer* 		layer()   const
         {
             if (object_layer != nullptr)
@@ -315,11 +327,25 @@ public:
                 count++;
             }
 
+            // A brim-only apron band contributes no object/support layer, and
+            // averaging zero terms would yield NaN.  Never folded into the
+            // average, so the non-belt result is bit-identical.
+            if (count == 0 && belt_brim_band != nullptr)
+                return belt_brim_band->print_z;
+
             return sum_z / count;
         }
     };
 
-private:
+    // Public accessor for the first-layer plane evaluator.  Used by
+    // CoolingBuffer (which is constructed with a GCode reference and needs
+    // to read the plane for per-segment fan re-evaluation).  All other
+    // first-layer-plane access points (on_first_layer overload, effective
+    // index helper) are in the protected section since they're called from
+    // GCode internals only.
+    const FirstLayerPlane *first_layer_plane() const { return m_first_layer_plane.get(); }
+
+protected:
     class GCodeOutputStream {
     public:
         GCodeOutputStream(FILE *f, GCodeProcessor &processor) : f(f), m_processor(processor) {}
@@ -347,9 +373,17 @@ private:
         FILE *f = nullptr;
         GCodeProcessor &m_processor;
     };
+
+    // Virtual hooks for belt printer subclass (BeltGCode).
+    // No-ops in base GCode; overridden in BeltGCode.
+    virtual void init_belt_writer(Print &print, bool is_bbl_printers) {}
+    virtual void write_belt_header(GCodeOutputStream &file, const Print &print) {}
+    virtual void on_set_origin(const PrintObject *obj, const Point &inst_shift) {}
+    virtual bool should_disable_arc_fitting() const { return false; }
+
     void            _do_export(Print &print, GCodeOutputStream &file, ThumbnailsGeneratorCallback thumbnail_cb);
 
-    static std::vector<LayerToPrint>        		                   collect_layers_to_print(const PrintObject &object);
+    static std::vector<LayerToPrint>        		                   collect_layers_to_print(const PrintObject &object, bool skip_empty_first_layer = false);
     static std::vector<std::pair<coordf_t, std::vector<LayerToPrint>>> collect_layers_to_print(const Print &print);
 
     std::string generate_skirt(const Print &print,
@@ -369,7 +403,28 @@ private:
     std::string generate_object_brim(const Print &print,
         const PrintObject &object,
         size_t instance_id,
-        bool first_layer);
+        bool first_layer,
+        const Layer *object_layer);
+
+    // Belt printers: emit one brim-only apron layer.  These print below the
+    // object's first layer, so there is no object or support layer for the normal
+    // process_layer() machinery to work from.  Kept to the minimum a layer needs -
+    // tool, Z move, extrusions - so that nothing here can perturb the
+    // Layer::id()-based logic the ordinary path relies on.
+    LayerResult process_belt_brim_layer(
+        const Print                     &print,
+        const std::vector<LayerToPrint> &layers,
+        const LayerTools                &layer_tools,
+        const bool                       last_layer,
+        const size_t                     single_object_instance_idx);
+
+    // Emit the apron bands carried by these layers.  Called from both the brim-only
+    // branch and the ordinary path, since a band's print_z can coincide with another
+    // object's layer on a multi-object belt.
+    std::string emit_belt_brim_bands(
+        const Print                     &print,
+        const std::vector<LayerToPrint> &layers,
+        const size_t                     single_object_instance_idx);
 
     LayerResult process_layer(
         const Print                     &print,
@@ -587,7 +642,7 @@ private:
     DynamicConfig                       m_calib_config;
     // scaled G-code resolution
     double                              m_scaled_resolution;
-    GCodeWriter                         m_writer;
+    std::unique_ptr<GCodeWriter>         m_writer;
 
     struct PlaceholderParserIntegration {
         void reset();
@@ -707,6 +762,11 @@ private:
 
     std::unique_ptr<CoolingBuffer>      m_cooling_buffer;
     std::unique_ptr<SpiralVase>         m_spiral_vase;
+    // First-layer plane evaluator.  Constructed once per print from the
+    // PrintConfig.  is_active() == false on non-belt printers and on belt
+    // printers without a Z-axis shear; in that case all per-path plane
+    // checks short-circuit to the legacy Layer::id() == 0 path.
+    std::unique_ptr<FirstLayerPlane>    m_first_layer_plane;
 
     std::unique_ptr<PressureEqualizer>  m_pressure_equalizer;
     
@@ -760,6 +820,13 @@ private:
     // resolvers. Distinct from m_layer_index (an export progress counter starting at -1).
     size_t m_cur_layer_idx{0};
 
+    // Belt brim apron layers only.  They have no Layer, so the print_z that
+    // _extrude() needs for the first-layer-plane probe is published here instead.
+    // Scoped by BeltBrimZGuard in process_belt_brim_layer(), never left set.
+    std::optional<coordf_t> m_belt_brim_z;
+    // Counter standing in for Layer::id() on apron layers, which precede layer 0.
+    size_t m_belt_brim_layer_idx{0};
+
     std::set<unsigned int>                  m_initial_layer_extruders;
     std::vector<std::vector<unsigned int>>  m_sorted_layer_filaments;
     // BBS
@@ -777,6 +844,25 @@ private:
     // On the first printing layer. This flag triggers first layer speeds.
     //BBS
     bool    on_first_layer() const { return m_layer != nullptr && m_layer->id() == 0 && abs(m_layer->bottom_z()) < EPSILON; }
+    // Per-point first-layer test.  When the FirstLayerPlane evaluator is
+    // active, the result depends on the supplied slicing-frame point;
+    // otherwise we delegate to the legacy per-layer test.  This is the
+    // entry point used by per-path call sites in _extrude.
+    bool on_first_layer(const Vec3d &point_slicing_mm) const {
+        if (m_first_layer_plane && m_first_layer_plane->is_active())
+            return m_first_layer_plane->is_first_layer(
+                point_slicing_mm, m_config.initial_layer_print_height.value);
+        return on_first_layer();
+    }
+    // "Effective layer index" used to drive layer-count thresholds like
+    // slow_down_layers.  When the evaluator is active this returns the
+    // perpendicular distance to the plane in band_thickness_mm units;
+    // otherwise it returns the legacy slicing layer index.
+    int effective_layer_index_for_point(const Vec3d &point_slicing_mm) const {
+        if (m_first_layer_plane && m_first_layer_plane->is_active())
+            return m_first_layer_plane->effective_layer_index(point_slicing_mm);
+        return on_first_layer() ? 0 : layer_id();
+    }
     int layer_id() const {
         if (m_layer == nullptr)
             return -1;

src/libslic3r/GCode/BeltBackTransform.cpp

@@ -0,0 +1,40 @@
+#include "BeltBackTransform.hpp"
+#include "../BeltTransform.hpp"
+
+namespace Slic3r {
+
+bool BeltBackTransform::init_from_config(const PrintConfig &config)
+{
+    m_active  = false;
+    m_inverse = Transform3d::Identity();
+
+    if (!config.belt_printer.value || !config.gcode_back_transform.value)
+        return false;
+
+    // Require at least one active transform to proceed.
+    bool has_global_rotation = config.belt_slice_rotation_global.value
+                            && config.belt_slice_rotation.value != BeltRotationAxis::None;
+    bool has_preslice_global = config.belt_preslice_global.value
+                            || config.preslice_remap_global.value;
+    if (!has_global_rotation && !has_preslice_global
+        && !BeltTransformPipeline::has_preslice_remap(config))
+        return false;
+
+    // Build the forward pipeline (rotation * pre_remap) and store its inverse.
+    Transform3d forward = BeltTransformPipeline::build_forward_transform(config);
+    if (forward.isApprox(Transform3d::Identity()))
+        return false;
+
+    m_inverse = forward.inverse();
+    m_active  = true;
+    return true;
+}
+
+Vec3d BeltBackTransform::apply(const Vec3d &pos) const
+{
+    if (!m_active)
+        return pos;
+    return m_inverse * pos;
+}
+
+} // namespace Slic3r

src/libslic3r/GCode/BeltBackTransform.hpp

@@ -0,0 +1,45 @@
+#ifndef slic3r_BeltBackTransform_hpp_
+#define slic3r_BeltBackTransform_hpp_
+
+#include "../libslic3r.h"
+#include "../Point.hpp"
+#include "../PrintConfig.hpp"
+
+namespace Slic3r {
+
+// Reverses the pre-slice remap + shear + scale transforms that
+// PrintObjectSlice.cpp applies to belt printer geometry, converting G-code
+// coordinates from the sliced (remapped/sheared/scaled) frame back to the
+// machine's real coordinate space.
+//
+// Initialized once from PrintConfig, then applied per-point in
+// GCodeWriter::to_machine_coords() before axis remapping.
+//
+// Active when gcode_back_transform is true AND at least one of:
+//   - a shear axis has global mode enabled, or
+//   - a pre-slice axis remap is non-identity.
+class BeltBackTransform
+{
+public:
+    BeltBackTransform() = default;
+
+    // Initialize from belt printer config.  Rebuilds the same pre-slice remap,
+    // shear, and scale matrices as PrintObjectSlice.cpp and precomputes the
+    // affine inverse.  Returns true if a non-identity back-transform was computed.
+    bool init_from_config(const PrintConfig &config);
+
+    // Apply the inverse transform to a point.  Returns pos unchanged if
+    // no back-transform is active.
+    Vec3d apply(const Vec3d &pos) const;
+
+    // True if a non-identity back-transform is active.
+    bool is_active() const { return m_active; }
+
+private:
+    bool       m_active  = false;
+    Transform3d m_inverse = Transform3d::Identity();
+};
+
+} // namespace Slic3r
+
+#endif // slic3r_BeltBackTransform_hpp_

src/libslic3r/GCode/CoolingBuffer.cpp

@@ -1,10 +1,14 @@
 #include "../GCode.hpp"
+#include "../FirstLayerPlane.hpp"
 #include "CoolingBuffer.hpp"
 #include <boost/algorithm/string/predicate.hpp>
 #include <boost/algorithm/string/replace.hpp>
 #include <boost/log/trivial.hpp>
+#include <algorithm>
+#include <cstdlib>
 #include <iostream>
 #include <float.h>
+#include <string_view>
 #include <system_error>
 #include <unordered_map>
 
@@ -28,6 +32,12 @@ CoolingBuffer::CoolingBuffer(GCode &gcodegen) : m_config(gcodegen.config()), m_t
         m_num_extruders = std::max(ex.id() + 1, m_num_extruders);
         m_extruder_ids.emplace_back(ex.id());
     }
+
+    // Borrow the first-layer plane from the GCode generator.  When inactive
+    // (non-belt printers and belt printers without Z shear), per-line fan
+    // re-evaluation is skipped and behavior is bit-identical to the legacy
+    // per-layer path.
+    m_first_layer_plane = gcodegen.first_layer_plane();
 }
 
 void CoolingBuffer::reset(const Vec3d &position)
@@ -328,6 +338,13 @@ std::string CoolingBuffer::process_layer(std::string &&gcode, size_t layer_id, b
         std::vector<PerExtruderAdjustments> per_extruder_adjustments = this->parse_layer_gcode(m_gcode, m_current_pos);
         float layer_time_stretched = this->calculate_layer_slowdown(per_extruder_adjustments);
         out = this->apply_layer_cooldown(m_gcode, layer_id, layer_time_stretched, per_extruder_adjustments);
+        // First-layer plane: per-segment fan re-evaluation post-pass.  Walks
+        // the cooled-down gcode and inserts inline M106 commands at band
+        // crossings (where the path's perpendicular distance to the plane
+        // crosses close_fan_the_first_x_layers thresholds).  No-op when
+        // the evaluator is inactive.
+        if (m_first_layer_plane && m_first_layer_plane->is_active())
+            out = this->apply_first_layer_plane_fan_eval(std::move(out), layer_id, layer_time_stretched);
         m_gcode.clear();
     }
     return out;
@@ -1059,4 +1076,214 @@ std::string CoolingBuffer::apply_layer_cooldown(
     return new_gcode;
 }
 
+// Pure helper: compute the main fan speed for a given effective layer index.
+// Mirrors the inline logic in change_extruder_set_fan but is callable from
+// per-line code in apply_first_layer_plane_fan_eval.
+int CoolingBuffer::compute_main_fan_speed(int effective_layer_id, float layer_time,
+                                           unsigned int extruder_id) const
+{
+#define EXTRUDER_CFG(opt) m_config.opt.get_at(extruder_id)
+    float fan_min_speed              = EXTRUDER_CFG(fan_min_speed);
+    float fan_max_speed              = EXTRUDER_CFG(fan_max_speed);
+    bool  reduce_fan_stop_start_freq = EXTRUDER_CFG(reduce_fan_stop_start_freq);
+    int   close_fan_the_first_x_layers = EXTRUDER_CFG(close_fan_the_first_x_layers);
+    int   full_fan_speed_layer       = EXTRUDER_CFG(full_fan_speed_layer);
+    float slow_down_layer_time       = float(EXTRUDER_CFG(slow_down_layer_time));
+    float fan_cooling_layer_time     = float(EXTRUDER_CFG(fan_cooling_layer_time));
+#undef EXTRUDER_CFG
+
+    if (close_fan_the_first_x_layers <= 0 && full_fan_speed_layer > 0)
+        close_fan_the_first_x_layers = 1;
+
+    float fan_speed_new = reduce_fan_stop_start_freq ? fan_min_speed : 0.f;
+    if (effective_layer_id >= close_fan_the_first_x_layers) {
+        if (layer_time < slow_down_layer_time) {
+            fan_speed_new = fan_max_speed;
+        } else if (layer_time < fan_cooling_layer_time) {
+            double t = (layer_time - slow_down_layer_time) /
+                       (fan_cooling_layer_time - slow_down_layer_time);
+            fan_speed_new = float(int(floor(t * fan_min_speed +
+                                            (1. - t) * fan_max_speed) + 0.5));
+        }
+        if (effective_layer_id + 1 < full_fan_speed_layer) {
+            float factor = float(effective_layer_id + 1 - close_fan_the_first_x_layers)
+                         / float(full_fan_speed_layer - close_fan_the_first_x_layers);
+            fan_speed_new = float(std::clamp(int(fan_speed_new * factor + 0.5f), 0, 255));
+        }
+    } else {
+        fan_speed_new = 0.f;
+    }
+    return int(fan_speed_new);
+}
+
+// Post-pass: walk the cooled-down gcode line by line, track XYZ position,
+// and insert M106 commands at first-layer-plane band crossings so the fan
+// follows perpendicular distance to the plane rather than the slicing-layer
+// index.  Only invoked when the FirstLayerPlane evaluator is active.
+//
+// This implementation is intentionally minimal: it overrides only the MAIN
+// fan (the one set by GCodeWriter::set_fan); overhang/internal-bridge/etc
+// special fans remain at their layer-level values from apply_layer_cooldown.
+// That keeps the per-line logic small while still giving the user precise
+// fan control near the belt surface, which is the main quality concern.
+std::string CoolingBuffer::apply_first_layer_plane_fan_eval(
+    std::string &&gcode_in, size_t /*layer_id*/, float layer_time)
+{
+    if (!m_first_layer_plane || !m_first_layer_plane->is_active())
+        return std::move(gcode_in);
+
+    const std::string &gcode = gcode_in;
+    std::string out;
+    out.reserve(gcode.size() + 256);
+
+    // Match the PWM floor applied at every other set_fan call in this file so
+    // band-crossing M106 emissions start the fan reliably at low speeds.
+    const unsigned int part_cooling_fan_min_pwm = static_cast<unsigned int>(std::max(0, m_config.part_cooling_fan_min_pwm.value));
+
+    // Track position in slicing-frame mm.  Seed from m_current_pos which the
+    // CoolingBuffer keeps up-to-date across layers.
+    Vec3d cur_pos_mm(m_current_pos[0], m_current_pos[1], m_current_pos[2]);
+
+    // Track current main fan speed by parsing M106 commands as we walk so
+    // we can restore it after a band exit.
+    int  current_main_fan = m_fan_speed;
+    int  pre_band_main_fan = current_main_fan;
+    // Implicit initial state: assume the layer started "out of the band"
+    // (i.e., the layer-level fan setting from apply_layer_cooldown is in
+    // effect).  The first movement we encounter will reconcile this.
+    bool in_first_layer_band = false;
+    unsigned int active_extruder = m_current_extruder;
+
+    auto parse_xyz_into = [](const std::string_view &line_sv, Vec3d &p) {
+        if (line_sv.size() < 3) return false;
+        if (line_sv[0] != 'G') return false;
+        if (line_sv[1] != '0' && line_sv[1] != '1') return false;
+        if (line_sv[2] != ' ' && line_sv[2] != '\t') return false;
+        const char *c   = line_sv.data() + 3;
+        const char *end = line_sv.data() + line_sv.size();
+        bool        any = false;
+        while (c < end && *c != ';') {
+            while (c < end && (*c == ' ' || *c == '\t')) ++c;
+            if (c >= end || *c == ';' || *c == '\n' || *c == '\r') break;
+            char axis = *c;
+            ++c;
+            if (axis == 'X' || axis == 'Y' || axis == 'Z') {
+                char *next;
+                double v = std::strtod(c, &next);
+                if (next != c) {
+                    if (axis == 'X') p.x() = v;
+                    else if (axis == 'Y') p.y() = v;
+                    else                  p.z() = v;
+                    c   = next;
+                    any = true;
+                    continue;
+                }
+            }
+            // Skip unrecognized word.
+            while (c < end && *c != ' ' && *c != '\t' && *c != ';' && *c != '\n')
+                ++c;
+        }
+        return any;
+    };
+
+    auto parse_m106 = [](const std::string_view &line_sv) -> int {
+        // Returns -1 if not an M106, otherwise the S value (0..255).
+        if (line_sv.size() < 4 || line_sv[0] != 'M') return -1;
+        if (!(line_sv[1] == '1' && line_sv[2] == '0' && line_sv[3] == '6'))
+            return -1;
+        // Find S<value>
+        size_t s_pos = line_sv.find('S');
+        if (s_pos == std::string_view::npos) return -1;
+        const char *c = line_sv.data() + s_pos + 1;
+        char *next;
+        long v = std::strtol(c, &next, 10);
+        if (next == c) return -1;
+        return int(std::clamp<long>(v, 0, 255));
+    };
+
+    auto parse_m107 = [](const std::string_view &line_sv) -> bool {
+        return line_sv.size() >= 4 && line_sv[0] == 'M' &&
+               line_sv[1] == '1' && line_sv[2] == '0' && line_sv[3] == '7';
+    };
+
+    auto parse_tool_change = [this](const std::string_view &line_sv) -> int {
+        // Returns the new extruder id, or -1 if not a toolchange.
+        if (line_sv.size() < m_toolchange_prefix.size() + 1) return -1;
+        if (line_sv.compare(0, m_toolchange_prefix.size(), m_toolchange_prefix) != 0)
+            return -1;
+        const char *c = line_sv.data() + m_toolchange_prefix.size();
+        char *next;
+        long v = std::strtol(c, &next, 10);
+        if (next == c) return -1;
+        return int(v);
+    };
+
+    const char *p   = gcode.c_str();
+    const char *end = gcode.c_str() + gcode.size();
+    while (p < end) {
+        const char *line_end = p;
+        while (line_end < end && *line_end != '\n') ++line_end;
+        const char *next_line = line_end;
+        if (next_line < end) ++next_line;  // include the '\n'
+
+        std::string_view line_sv(p, line_end - p);
+
+        // Track tool changes so the per-line fan eval uses the right extruder.
+        int new_tool = parse_tool_change(line_sv);
+        if (new_tool >= 0)
+            active_extruder = unsigned(new_tool);
+
+        // Track existing fan commands so we can restore the right value when
+        // exiting a band.
+        int m106_speed = parse_m106(line_sv);
+        if (m106_speed >= 0) {
+            current_main_fan = m106_speed;
+            if (!in_first_layer_band)
+                pre_band_main_fan = m106_speed;
+        } else if (parse_m107(line_sv)) {
+            current_main_fan = 0;
+            if (!in_first_layer_band)
+                pre_band_main_fan = 0;
+        }
+
+        // Movement line: parse XYZ, evaluate plane, possibly emit a fan
+        // change BEFORE this line.
+        bool moved = parse_xyz_into(line_sv, cur_pos_mm);
+        if (moved) {
+            const int eff_idx = m_first_layer_plane->effective_layer_index(cur_pos_mm);
+            const int close_n = m_config.close_fan_the_first_x_layers.get_at(active_extruder);
+            const bool now_in_band = eff_idx < std::max(close_n, 1);
+            if (now_in_band != in_first_layer_band) {
+                // Band crossing: emit a M106 with the appropriate speed.
+                int target_fan;
+                if (now_in_band) {
+                    // Entering the first-layer band: fan off.
+                    pre_band_main_fan = current_main_fan;
+                    target_fan = compute_main_fan_speed(eff_idx, layer_time, active_extruder);
+                } else {
+                    // Exiting the band: restore the layer's normal fan speed.
+                    // Use compute_main_fan_speed with the effective index so
+                    // the linear ramp factor (close_fan→full_fan_speed_layer)
+                    // also follows distance from the plane.
+                    target_fan = compute_main_fan_speed(eff_idx, layer_time, active_extruder);
+                    if (target_fan == 0)
+                        target_fan = pre_band_main_fan;
+                }
+                if (target_fan != current_main_fan) {
+                    out += GCodeWriter::set_fan(m_config.gcode_flavor, target_fan, part_cooling_fan_min_pwm);
+                    current_main_fan = target_fan;
+                    m_fan_speed = target_fan;
+                    m_current_fan_speed = target_fan;
+                }
+                in_first_layer_band = now_in_band;
+            }
+        }
+
+        out.append(p, next_line - p);
+        p = next_line;
+    }
+
+    return out;
+}
+
 } // namespace Slic3r

src/libslic3r/GCode/CoolingBuffer.hpp

@@ -10,6 +10,7 @@ namespace Slic3r {
 
 class GCode;
 class Layer;
+class FirstLayerPlane;
 struct PerExtruderAdjustments;
 
 // A standalone G-code filter, to control cooling of the print.
@@ -18,7 +19,7 @@ struct PerExtruderAdjustments;
 //
 // The simple it sounds, the actual implementation is significantly more complex.
 // Namely, for a multi-extruder print, each material may require a different cooling logic.
-// For example, some materials may not like to print too slowly, while with some materials 
+// For example, some materials may not like to print too slowly, while with some materials
 // we may slow down significantly.
 //
 class CoolingBuffer {
@@ -36,6 +37,21 @@ private:
     // Returns the adjusted G-code.
     std::string apply_layer_cooldown(const std::string &gcode, size_t layer_id, float layer_time, std::vector<PerExtruderAdjustments> &per_extruder_adjustments);
 
+    // First-layer plane: per-line fan re-evaluation post-pass.  Walks the
+    // post-cooldown gcode, tracks XYZ position, and inserts M106 commands at
+    // band-crossing transitions in slicing-frame coordinates.  Only runs
+    // when m_first_layer_plane is active.
+    std::string apply_first_layer_plane_fan_eval(std::string &&gcode_in,
+                                                  size_t        layer_id,
+                                                  float         layer_time);
+
+    // Pure helper: compute the main fan speed for a given effective layer
+    // index (layer-id units, mapped through the plane evaluator) and the
+    // current extruder.  Mirrors the inline logic in the change_extruder_set_fan
+    // lambda but is callable from per-line code.
+    int compute_main_fan_speed(int effective_layer_id, float layer_time,
+                               unsigned int extruder_id) const;
+
     // G-code snippet cached for the support layers preceding an object layer.
     std::string                 m_gcode;
     // Internal data.
@@ -58,6 +74,9 @@ private:
     unsigned int                m_current_nozzle;
     //BBS: current fan speed
     int                         m_current_fan_speed;
+    // First-layer plane evaluator, borrowed from GCode.  Null = inactive
+    // (legacy per-layer fan control).
+    const FirstLayerPlane      *m_first_layer_plane = nullptr;
 };
 
 }

src/libslic3r/GCode/GCodeProcessor.cpp

@@ -2533,6 +2533,12 @@ void GCodeProcessorResult::reset() {
     long_retraction_when_cut = false;
     timelapse_warning_code = 0;
     printable_height = 0.0f;
+    machine_frame_transform_active = false;
+    belt_tilt_angle = 0.f;
+    belt_z_origin   = 0.f;
+    preslice_remap_x = RemapAxis::PosX;
+    preslice_remap_y = RemapAxis::PosY;
+    preslice_remap_z = RemapAxis::PosZ;
     settings_ids.reset();
     filaments_count = 0;
     backtrace_enabled = false;
@@ -2769,6 +2775,32 @@ bool GCodeProcessor::check_multi_extruder_gcode_valid(const int
         return ps;
     };
 
+    // Belt-printer post-gcode shear/scale/post_remap is applied as the final
+    // step of BeltGCodeWriter::to_machine_coords, so MoveVertex.position is
+    // in the printer's machine frame.  Undo it here so XY area and Z height
+    // checks operate in the build-volume frame that printable_area /
+    // printable_height are defined in.  For non-belt printers
+    // (is_active() == false) apply_inverse is identity and behaviour is
+    // unchanged from before.
+    const bool machine_frame_active = m_machine_frame_transform.is_active();
+    auto compare_pos = [&](const GCodeProcessorResult::MoveVertex &move) -> Vec3d {
+        Vec3d pos = move.position.cast<double>();
+        if (!machine_frame_active)
+            return pos;
+        Vec3d extruder_off = Vec3d::Zero();
+        if (size_t(move.extruder_id) < m_extruder_offsets.size())
+            extruder_off = m_extruder_offsets[move.extruder_id].cast<double>();
+        // Strip plate + extruder offsets to recover the raw machine-frame
+        // coordinate that was emitted into the G-code (see store_move_vertex).
+        Vec3d machine(pos.x() - m_x_offset - extruder_off.x(),
+                      pos.y() - m_y_offset - extruder_off.y(),
+                      pos.z() - extruder_off.z() + m_z_offset);
+        Vec3d build = m_machine_frame_transform.apply_inverse(machine);
+        // Re-apply plate offset so the result matches plate_printable_poly,
+        // which is translated by plate_offset below.
+        return Vec3d(build.x() + m_x_offset, build.y() + m_y_offset, build.z());
+    };
+
     struct GCodePosInfo
     {
         Points pos;
@@ -2780,26 +2812,20 @@ bool GCodeProcessor::check_multi_extruder_gcode_valid(const int
     for (const GCodeProcessorResult::MoveVertex &move : m_result.moves) {
         // sometimes, the start line extrude was outside the edge of plate a little, this is allowed, so do not include into the gcode_path_pos
         if (move.type == EMoveType::Extrude /* && move.extrusion_role != ExtrusionRole::erFlush || move.type == EMoveType::Travel*/) {
+            const Vec3d cp = compare_pos(move);
+            // For belt printers we read Z from the inverse-transformed position
+            // (post-origin-snap, pre-machine-frame).  Otherwise keep the
+            // original print_z source (the slicer's layer-Z comment) so
+            // non-belt behaviour is bit-for-bit unchanged.
+            const float z_for_height = machine_frame_active ? float(cp.z()) : move.print_z;
             if (move.extrusion_role == ExtrusionRole::erCustom) {
-                /*if (move.is_arc_move_with_interpolation_points()) {
+                gcode_path_pos[move.object_label_id][int(move.extruder_id)].pos_custom.emplace_back(to_2d(cp));
-                    for (int i = 0; i < move.interpolation_points.size(); i++) {
-                        gcode_path_pos[move.object_label_id][int(move.extruder_id)].pos_custom.emplace_back(to_2d(move.interpolation_points[i].cast<double>()));
-                    }
-                } else {*/
-                    gcode_path_pos[move.object_label_id][int(move.extruder_id)].pos_custom.emplace_back(to_2d(move.position.cast<double>()));
-                //}
                 gcode_path_pos[move.object_label_id][int(move.extruder_id)].max_print_z_custom =
-                    std::max(gcode_path_pos[move.object_label_id][int(move.extruder_id)].max_print_z_custom, move.print_z);
+                    std::max(gcode_path_pos[move.object_label_id][int(move.extruder_id)].max_print_z_custom, z_for_height);
             } else {
-                /*if (move.is_arc_move_with_interpolation_points()) {
+                gcode_path_pos[move.object_label_id][int(move.extruder_id)].pos.emplace_back(to_2d(cp));
-                    for (int i = 0; i < move.interpolation_points.size(); i++) {
-                        gcode_path_pos[move.object_label_id][int(move.extruder_id)].pos.emplace_back(to_2d(move.interpolation_points[i].cast<double>()));
-                    }
-                } else {*/
-                    gcode_path_pos[move.object_label_id][int(move.extruder_id)].pos.emplace_back(to_2d(move.position.cast<double>()));
-                //}
                 gcode_path_pos[move.object_label_id][int(move.extruder_id)].max_print_z = std::max(gcode_path_pos[move.object_label_id][int(move.extruder_id)].max_print_z,
-                                                                                                   move.print_z);
+                                                                                                   z_for_height);
             }
         }
     }
@@ -3041,6 +3067,12 @@ void GCodeProcessor::apply_config(const PrintConfig& config)
 
     m_result.printable_height = config.printable_height;
 
+    // Belt printer: cache the post-gcode machine-frame transform so the
+    // multi-extruder validator can undo it and compare against build-volume
+    // bounds rather than machine-frame positions.
+    m_machine_frame_transform.init_from_config(config);
+    m_result.machine_frame_transform_active = m_machine_frame_transform.is_active();
+
     auto filament_maps = config.option<ConfigOptionInts>("filament_map");
     if (filament_maps != nullptr) {
         m_filament_maps = filament_maps->values;
@@ -4159,6 +4191,44 @@ void GCodeProcessor::process_tags(const std::string_view comment, bool producers
         return;
     }
 
+    // Belt printer: derive the physical tilt magnitude from the slicing-rotation
+    // angle header comment (used to enable the preview's belt view).
+    if (boost::starts_with(comment, " belt_slice_rotation_angle = ")) {
+        try {
+            m_result.belt_tilt_angle = std::abs(std::stof(std::string(comment.substr(29))));
+        } catch (...) {}
+        return;
+    }
+    // Belt printer: parse pre-slice axis remap from header comments.
+    {
+        auto trim = [](const std::string &s) -> std::string {
+            size_t start = s.find_first_not_of(" \t\r\n");
+            size_t end   = s.find_last_not_of(" \t\r\n");
+            return (start == std::string::npos) ? "" : s.substr(start, end - start + 1);
+        };
+        // Pre-slice axis remap
+        auto parse_remap_axis = [](const std::string &s) -> RemapAxis {
+            if (s == "pos_x") return RemapAxis::PosX;
+            if (s == "pos_y") return RemapAxis::PosY;
+            if (s == "pos_z") return RemapAxis::PosZ;
+            if (s == "neg_x") return RemapAxis::NegX;
+            if (s == "neg_y") return RemapAxis::NegY;
+            if (s == "neg_z") return RemapAxis::NegZ;
+            if (s == "rev_x") return RemapAxis::RevX;
+            if (s == "rev_y") return RemapAxis::RevY;
+            if (s == "rev_z") return RemapAxis::RevZ;
+            return RemapAxis::PosX;
+        };
+        if (boost::starts_with(comment, " preslice_remap_x = ")) {
+            m_result.preslice_remap_x = parse_remap_axis(trim(std::string(comment.substr(25)))); return;
+        }
+        if (boost::starts_with(comment, " preslice_remap_y = ")) {
+            m_result.preslice_remap_y = parse_remap_axis(trim(std::string(comment.substr(25)))); return;
+        }
+        if (boost::starts_with(comment, " preslice_remap_z = ")) {
+            m_result.preslice_remap_z = parse_remap_axis(trim(std::string(comment.substr(25)))); return;
+        }
+    }
     // wipe start tag
     if (boost::starts_with(comment, reserved_tag(ETags::Wipe_Start))) {
         m_wiping = true;
@@ -6055,6 +6125,13 @@ void GCodeProcessor::process_G92(const GCodeReader::GCodeLine& line)
     if (line.has_z()) {
         m_origin[Z] = m_end_position[Z] - line.z() * lengths_scale_factor;
         any_found = true;
+        // Belt only: the start G-code's purge-blob advance + G92 Z0 resets leave a constant
+        // machine-Z origin offset here; the designed-view back-transform subtracts it so
+        // toolpaths map to the model's belt coordinate (gcode Z). Gated on belt_tilt_angle
+        // (set from the belt header, parsed before the body) so non-belt G-code processing
+        // is byte-identical — no unconditional work on the shared path.
+        if (m_result.belt_tilt_angle != 0.f)
+            m_result.belt_z_origin = m_origin[Z];
     }
 
     if (line.has_e()) {
@@ -7033,6 +7110,22 @@ void GCodeProcessor::store_move_vertex(EMoveType type, EMovePathType path_type,
         m_result.print_statistics.total_travel_distance += m_travel_dist;
     }
 
+    // During the start G-code "prepare" stage the toolhead Z is not yet a real
+    // print height on a normal printer, so it is pinned to the first-layer height
+    // to keep the preview tidy. Belt printers are the exception: there the Z is
+    // written explicitly by BeltGCodeWriter and the designed-view back-transform
+    // couples machine Z into the rendered model Y (the belt tilt mixes the height
+    // and belt-feed axes). Overriding Z therefore back-transforms the last
+    // prepare-stage move (the unretract before the first extrusion) to model
+    // Y ~= 0, and the libvgcode path builder then draws a phantom extrusion
+    // segment from Y ~= 0 to the first real toolpath. Keep the real Z for belt
+    // printers so prepare-stage moves map correctly. Gated on belt_tilt_angle (set
+    // from the G-code header before the body is processed) so non-belt processing
+    // is byte-identical.
+    const float store_z = (m_processing_start_custom_gcode && m_result.belt_tilt_angle == 0.f)
+        ? m_first_layer_height
+        : m_end_position[Z] - m_z_offset;
+
     m_result.moves.push_back({
         m_last_line_id,
         type,
@@ -7040,7 +7133,7 @@ void GCodeProcessor::store_move_vertex(EMoveType type, EMovePathType path_type,
         static_cast<unsigned char>(filament_id),
         m_cp_color.current,
         //BBS: add plate's offset to the rendering vertices
-        Vec3f(m_end_position[X] + m_x_offset, m_end_position[Y] + m_y_offset, m_processing_start_custom_gcode ? m_first_layer_height : m_end_position[Z]- m_z_offset) + m_extruder_offsets[filament_id],
+        Vec3f(m_end_position[X] + m_x_offset, m_end_position[Y] + m_y_offset, store_z) + m_extruder_offsets[filament_id],
         static_cast<float>(m_end_position[E] - m_start_position[E]),
         m_feedrate,
         0.0f, // actual feedrate

src/libslic3r/GCode/GCodeProcessor.hpp

@@ -7,6 +7,7 @@
 #include "libslic3r/PrintConfig.hpp"
 #include "libslic3r/CustomGCode.hpp"
 #include "libslic3r/MultiNozzleUtils.hpp"
+#include "libslic3r/GCode/MachineFrameTransform.hpp"
 
 #include <cstdint>
 #include <array>
@@ -276,6 +277,22 @@ class Print;
         bool support_traditional_timelapse{true};
         float printable_height;
         float z_offset;
+        // Belt printer: physical tilt magnitude (deg) parsed from the slicing-rotation
+        // header comment; used to enable the preview's belt view.
+        float belt_tilt_angle{ 0.f };
+        // Belt printer: machine-Z origin offset (mm) left in m_origin[Z] by the start
+        // G-code (purge-blob belt advance + G92 Z0 resets). Move positions are stored
+        // as gcode_Z + this offset, so the designed-view back-transform must subtract it
+        // to recover the model's belt coordinate.
+        float belt_z_origin{ 0.f };
+        // Belt printer: post-gcode shear/scale/post_remap is configured and
+        // non-identity.  When set, the layer Z values in `moves` are in the
+        // machine frame and should not be compared against `printable_height`
+        // (which lives in the build-volume frame).
+        bool machine_frame_transform_active{ false };
+        RemapAxis preslice_remap_x{ RemapAxis::PosX };
+        RemapAxis preslice_remap_y{ RemapAxis::PosY };
+        RemapAxis preslice_remap_z{ RemapAxis::PosZ };
         SettingsIds settings_ids;
         size_t filaments_count;
         bool backtrace_enabled;
@@ -367,6 +384,12 @@ class Print;
             // Keep the SKIPPABLE per-type time on a copied result.
             skippable_part_time = other.skippable_part_time;
             initial_layer_time = other.initial_layer_time;
+            belt_tilt_angle = other.belt_tilt_angle;
+            belt_z_origin = other.belt_z_origin;
+            machine_frame_transform_active = other.machine_frame_transform_active;
+            preslice_remap_x = other.preslice_remap_x;
+            preslice_remap_y = other.preslice_remap_y;
+            preslice_remap_z = other.preslice_remap_z;
 #if ENABLE_GCODE_VIEWER_STATISTICS
             time = other.time;
 #endif
@@ -1136,6 +1159,12 @@ class Print;
         double          m_x_offset{ 0 };
         double          m_y_offset{ 0 };
 
+        // Belt-printer post-gcode shear/scale/post_remap. Used by
+        // check_multi_extruder_gcode_valid to undo the machine-frame
+        // transform on move positions so bounds checks operate in the
+        // pre-machine-frame (build-volume) frame.
+        MachineFrameTransform m_machine_frame_transform;
+
         unsigned int m_line_id;
         unsigned int m_last_line_id;
         float m_feedrate; // mm/s

src/libslic3r/GCode/MachineFrameTransform.cpp

@@ -0,0 +1,86 @@
+#include "MachineFrameTransform.hpp"
+#include "../Geometry.hpp"
+
+#include <cmath>
+
+namespace Slic3r {
+
+bool MachineFrameTransform::init_from_config(const PrintConfig &config)
+{
+    m_active            = false;
+    m_transform         = Transform3d::Identity();
+    m_transform_inverse = Transform3d::Identity();
+
+    if (!config.belt_printer.value)
+        return false;
+
+    // The machine-frame transform is derived from the single belt tilt (axis +
+    // angle) that also drives the pre-slice mesh rotation.  Expert decouple lets
+    // the machine-frame angle differ from the slicing rotation; otherwise both
+    // use belt_slice_rotation_angle.
+    const BeltRotationAxis axis = config.belt_slice_rotation.value;
+    if (axis == BeltRotationAxis::None || axis == BeltRotationAxis::Z)
+        return false; // Z is an in-plane spin: no machine-frame tilt.
+
+    const double angle_deg = config.belt_frame_tilt_decouple.value
+        ? config.belt_frame_tilt_angle.value
+        : config.belt_slice_rotation_angle.value;
+    if (std::abs(angle_deg) <= EPSILON)
+        return false;
+
+    const double angle_rad = Geometry::deg2rad(angle_deg);
+    const double sin_a      = std::sin(angle_rad);
+    if (std::abs(sin_a) <= EPSILON)
+        return false;
+    const double cot_a   = std::cos(angle_rad) / sin_a;
+    const double inv_sin = 1.0 / std::abs(sin_a);
+
+    // This stage runs after the conventional belt axis swap. For an X-axis
+    // slicing rotation, remapped Y is model height and remapped Z is travel
+    // along the belt. Convert those Cartesian coordinates to machine axes with
+    // the established belt-printer convention:
+    //   machine gantry = model height / sin(a)
+    //   machine belt   = model belt + model height * cot(a)
+    // The Y-rotation case is the same mapping on X/Z, with the rotation sign.
+    // At 45 degrees tan/cot and sin/cos are equal, which previously hid the
+    // incorrect complementary-angle formulas used by this unified transform.
+    Matrix3d shear = Matrix3d::Identity();
+    Matrix3d scale = Matrix3d::Identity();
+    if (axis == BeltRotationAxis::X) {
+        shear(2, 1) =  cot_a;   // Z from Y
+        scale(1, 1) =  inv_sin; // Y
+    } else { // BeltRotationAxis::Y
+        shear(2, 0) = -cot_a;   // Z from X
+        scale(0, 0) =  inv_sin; // X
+    }
+
+    // Apply shear first, then scale (the historical default ShearThenScale order:
+    // result = scale * shear * p).  For the canonical 45°/X belt this maps
+    // (x,y,z) -> (x, y/sin, y + z), matching the previous per-axis config.
+    Transform3d combined = Transform3d::Identity();
+    combined.linear() = scale * shear;
+
+    if (combined.isApprox(Transform3d::Identity()))
+        return false;
+
+    m_transform         = combined;
+    m_transform_inverse = combined.inverse();
+    m_active            = true;
+    return true;
+}
+
+Vec3d MachineFrameTransform::apply(const Vec3d &pos) const
+{
+    if (!m_active)
+        return pos;
+    return m_transform * pos;
+}
+
+Vec3d MachineFrameTransform::apply_inverse(const Vec3d &pos) const
+{
+    if (!m_active)
+        return pos;
+    return m_transform_inverse * pos;
+}
+
+} // namespace Slic3r

src/libslic3r/GCode/MachineFrameTransform.hpp

@@ -0,0 +1,54 @@
+#ifndef slic3r_MachineFrameTransform_hpp_
+#define slic3r_MachineFrameTransform_hpp_
+
+#include "../libslic3r.h"
+#include "../Point.hpp"
+#include "../PrintConfig.hpp"
+
+namespace Slic3r {
+
+// Post-stage machine-frame transform for belt printers.
+//
+// Applied in BeltGCodeWriter::to_machine_coords AFTER the back-transform and
+// the gcode_remap_* axis remap.  Maps Cartesian (axis-permuted) G-code
+// coordinates into the printer's physical machine frame.
+//
+// Derived entirely from the single belt tilt (belt_slice_rotation axis +
+// belt_slice_rotation_angle): a shear coupling the height axis to the belt-feed
+// axis (factor cot a) plus a 1/sin a scale on the gantry-height axis.  The expert
+// belt_frame_tilt_decouple flag lets the machine-frame angle differ from the
+// pre-slice rotation angle via belt_frame_tilt_angle.
+class MachineFrameTransform
+{
+public:
+    MachineFrameTransform() = default;
+
+    // Initialize from belt printer config.  Returns true if a non-identity
+    // transform was computed.  Inactive when belt_printer is disabled or
+    // both shear and scale are identity.
+    bool init_from_config(const PrintConfig &config);
+
+    // Apply the transform to a point.  Returns pos unchanged if not active.
+    Vec3d apply(const Vec3d &pos) const;
+
+    // Apply the inverse transform.  Returns pos unchanged if not active.
+    // Used by validators that need to compare emitted machine-frame
+    // coordinates against build-volume bounds.
+    Vec3d apply_inverse(const Vec3d &pos) const;
+
+    bool is_active() const { return m_active; }
+
+    // The composed shear*scale transform (identity when inactive). Exposed so the
+    // G-code viewer can build the machine->model back-transform for the upright
+    // ("designed") belt preview.
+    const Transform3d& transform() const { return m_transform; }
+
+private:
+    bool        m_active            = false;
+    Transform3d m_transform         = Transform3d::Identity();
+    Transform3d m_transform_inverse = Transform3d::Identity();
+};
+
+} // namespace Slic3r
+
+#endif // slic3r_MachineFrameTransform_hpp_

src/libslic3r/GCode/ToolOrdering.cpp

@@ -395,6 +395,10 @@ bool ToolOrdering::insert_wipe_tower_extruder()
 {
     if (!m_print_config_ptr || !m_print_config_ptr->enable_prime_tower)
         return false;
+    // Belt mode has no classic wipe tower; the dedicated wipe tower filament
+    // must not inject extra toolchanges into the purge prism planning.
+    if (m_print_config_ptr->belt_printer)
+        return false;
     if (m_print_config_ptr->wipe_tower_filament == 0)
         return false;
 
@@ -492,6 +496,11 @@ ToolOrdering::ToolOrdering(const PrintObject &object, unsigned int first_extrude
             zs.emplace_back(layer->print_z);
         for (auto layer : object.support_layers())
             zs.emplace_back(layer->print_z);
+        // Belt brim apron bands sit below the object's first layer and have no
+        // layer of their own, but tools_for_layer() asserts an exact Z match, so
+        // their print_z must be part of the ordering.
+        for (const BeltBrimBand &band : object.belt_brim_prologue())
+            zs.emplace_back(band.print_z);
         this->initialize_layers(zs);
     }
 
@@ -536,6 +545,10 @@ ToolOrdering::ToolOrdering(const Print &print, unsigned int first_extruder, bool
                 zs.emplace_back(layer->print_z);
             for (auto layer : object->support_layers())
                 zs.emplace_back(layer->print_z);
+            // See the single-object ctor: belt brim apron bands need their own
+            // ordering entries or tools_for_layer() will assert.
+            for (const BeltBrimBand &band : object->belt_brim_prologue())
+                zs.emplace_back(band.print_z);
 
             max_layer_height = std::max(max_layer_height, object->config().layer_height.value);
         }
@@ -970,6 +983,44 @@ void ToolOrdering::collect_extruders(const PrintObject &object, const std::vecto
         }
     }
 
+    // Belt brim apron bands own their layers outright: they print below the
+    // object's first layer, so no object or support layer claims an extruder there
+    // and process_layer() would bail out at "Nothing to extrude".  Claim the
+    // object's outer wall filament, in the same raw 1-based domain the loops above
+    // push.  Deliberately not layer_tools.has_object, which drives skirt marking
+    // and wiping overrides.
+    if (! object.belt_brim_prologue().empty()) {
+        // 1-based, same domain the object/support pushes above use; reindexed to 0-based
+        // with the rest of the list later.
+        const unsigned int brim_filament = object.belt_brim_filament();
+        for (const BeltBrimBand &band : object.belt_brim_prologue()) {
+            if (band.fills.empty())
+                continue;
+            LayerTools &layer_tools = this->tools_for_layer(band.print_z);
+            layer_tools.extruders.push_back(brim_filament);
+            layer_tools.has_belt_brim = true;
+        }
+    }
+
+    // Coincident brim bands (belt_brim_by_layer) print ON an object layer rather than
+    // below it, but that layer can produce no InstanceVisit in process_layer - a
+    // zero-extrusion lead-in slice with no coinciding support - and the band would then
+    // be silently dropped.  Register the brim filament on every layer that carries a
+    // coincident band, in the same 1-based domain as the prologue push above, so a brim
+    // pass always exists there.
+    if (object.has_belt_brim()) {
+        const unsigned int brim_filament = object.belt_brim_filament();
+        const auto        &by_layer      = object.belt_brim_by_layer();
+        const size_t       n             = std::min(by_layer.size(), object.layers().size());
+        for (size_t i = 0; i < n; ++ i) {
+            if (by_layer[i].empty())
+                continue;
+            LayerTools &layer_tools = this->tools_for_layer(object.layers()[i]->print_z);
+            layer_tools.extruders.push_back(brim_filament);
+            layer_tools.has_belt_brim = true;
+        }
+    }
+
     for (auto& layer : m_layer_tools) {
         // Sort and remove duplicates
         sort_remove_duplicates(layer.extruders);
@@ -1012,12 +1063,28 @@ void ToolOrdering::fill_wipe_tower_partitions(const PrintConfig &config, coordf_
     }
 
     //FIXME this is a hack to get the ball rolling.
+    // The `print_z < object_bottom_z` clause reads "below the object" as "raft
+    // gap".  On a belt printer that is wrong: the brim apron legitimately prints
+    // below the object's first layer, and treating those layers as raft would put a
+    // wipe tower at negative Z.  Belt brim and the prime tower are mutually
+    // exclusive (rejected in Print::validate()), so simply drop the clause there.
+    //
+    // Gate on config.belt_printer, NOT on has_belt_brim: every layer below the
+    // object bottom on a belt printer is legitimately a sub-object stream - brim
+    // apron, belt support printed below Z0, or the object's own lead-in - and none of
+    // them is ever raft, because Print::validate() rejects raft_layers>0 on a belt
+    // printer outright.  Narrowing this to has_belt_brim would reclassify
+    // belt-support-below-floor layers as raft on brim-less belt prints and reintroduce
+    // the negative-Z wipe tower, so the broad belt_printer gate is correct.
+    const bool belt_no_raft_gap = config.belt_printer.value;
     for (LayerTools &lt : m_layer_tools)
         lt.has_wipe_tower |= ((lt.has_object || lt.has_support) && (config.timelapse_type == TimelapseType::tlSmooth || lt.wipe_tower_partitions > 0))
-            || lt.print_z < object_bottom_z + EPSILON;
+            || (! belt_no_raft_gap && lt.print_z < object_bottom_z + EPSILON);
 
     // Test for a raft, insert additional wipe tower layer to fill in the raft separation gap.
-    for (size_t i = 0; i + 1 < m_layer_tools.size(); ++ i) {
+    // Skipped on belt printers for the same reason as the clause above: layers
+    // below the object are brim apron, not raft.
+    for (size_t i = 0; ! belt_no_raft_gap && i + 1 < m_layer_tools.size(); ++ i) {
         const LayerTools &lt      = m_layer_tools[i];
         const LayerTools &lt_next = m_layer_tools[i + 1];
         if (lt.print_z < object_bottom_z + EPSILON && lt_next.print_z >= object_bottom_z + EPSILON) {

src/libslic3r/GCode/ToolOrdering.hpp

@@ -75,6 +75,12 @@ public:
     void set_layer_tools_ptr(const LayerTools* lt) { m_layer_tools = lt; }
 
 private:
+    // Returns true if entity is not printed with its usual extruder for a given copy.
+    bool is_entity_overridden(const ExtrusionEntity* entity, const PrintObject *object, size_t copy_id) const {
+        auto it = entity_map.find(std::make_tuple(entity, object));
+        return it != entity_map.end() && copy_id < it->second.size() && it->second[copy_id] != -1;
+    }
+
     int first_nonsoluble_extruder_on_layer(const PrintConfig& print_config) const;
     int last_nonsoluble_extruder_on_layer(const PrintConfig& print_config) const;
 
@@ -84,12 +90,6 @@ private:
     void set_support_extruder_override(const PrintObject* object, size_t copy_id, int extruder, size_t num_of_copies);
     void set_support_interface_extruder_override(const PrintObject* object, size_t copy_id, int extruder, size_t num_of_copies);
 
-    // Returns true in case that entity is not printed with its usual extruder for a given copy:
-    bool is_entity_overridden(const ExtrusionEntity* entity, const PrintObject *object, size_t copy_id) const {
-        auto it = entity_map.find(std::make_tuple(entity, object));
-        return it == entity_map.end() ? false : it->second[copy_id] != -1;
-    }
-
     std::map<std::tuple<const ExtrusionEntity*, const PrintObject *>, ExtruderPerCopy> entity_map;  // to keep track of who prints what
     // BBS
     std::map<const PrintObject*, int> support_map;
@@ -165,6 +165,10 @@ public:
     // Should a skirt be printed at this layer?
     // Layers are marked for infinite skirt aka draft shield. Not all the layers have to be printed.
     bool                        has_skirt = false;
+    // Belt printers: is this one of the brim-only apron layers below the object's
+    // first layer?  Kept separate from has_object so skirt marking and wiping
+    // overrides are unaffected.
+    bool                        has_belt_brim = false;
     // Will there be anything extruded on this layer for the wipe tower?
     // Due to the support layers possibly interleaving the object layers,
     // wipe tower will be disabled for some support only layers.

src/libslic3r/GCodeWriter.cpp

@@ -1,5 +1,6 @@
 #include "GCodeWriter.hpp"
 #include "CustomGCode.hpp"
+#include "Geometry.hpp"
 #include "I18N.hpp"
 #include "PrintConfig.hpp"
 #include "ClipperUtils.hpp"
@@ -23,6 +24,36 @@ namespace Slic3r {
 
 bool GCodeWriter::full_gcode_comment = true;
 
+void GCodeWriter::set_axis_remap(int rx, int ry, int rz)
+{
+    m_remap_x = rx;
+    m_remap_y = ry;
+    m_remap_z = rz;
+}
+
+void GCodeWriter::set_build_volume_max(const Vec3d &max)
+{
+    m_build_vol_max = max;
+}
+
+bool GCodeWriter::has_axis_remap() const
+{
+    return m_remap_x != 0 || m_remap_y != 1 || m_remap_z != 2;
+}
+
+Vec3d GCodeWriter::apply_axis_remap(const Vec3d &pos) const
+{
+    if (!has_axis_remap())
+        return pos;
+    auto remap = [this, &pos](int r) -> double {
+        int axis = r % 3;
+        if (r < 3) return pos[axis];
+        if (r < 6) return -pos[axis];
+        return m_build_vol_max[axis] - pos[axis];
+    };
+    return { remap(m_remap_x), remap(m_remap_y), remap(m_remap_z) };
+}
+
 bool GCodeWriter::supports_separate_travel_acceleration(GCodeFlavor flavor)
 {
     return (flavor == gcfRepetier || flavor == gcfMarlinFirmware ||  flavor == gcfRepRapFirmware);
@@ -757,7 +788,13 @@ std::string GCodeWriter::travel_to_xy(const Vec2d &point, const std::string &com
     Vec2d point_on_plate = { point(0) - m_x_offset, point(1) - m_y_offset };
 
     GCodeG1Formatter w;
-    w.emit_xy(point_on_plate);
+    if (has_axis_remap()) {
+        // Axis remap may couple XY with Z; emit full XYZ in machine coordinates.
+        Vec3d machine = apply_axis_remap(Vec3d(point_on_plate.x(), point_on_plate.y(), m_pos.z()));
+        w.emit_xyz(machine);
+    } else {
+        w.emit_xy(point_on_plate);
+    }
     auto speed = m_is_first_layer
         ? this->config.get_abs_value_at("initial_layer_travel_speed", m_cached_extruder_idx) : this->config.travel_speed.get_at(m_cached_extruder_idx);
     w.emit_f(speed * 60.0);
@@ -797,8 +834,9 @@ std::string GCodeWriter::lazy_lift(LiftType lift_type, bool spiral_vase)
 }
 
 // BBS: immediately execute an undelayed lift move with a spiral lift pattern
-// designed specifically for subsequent gcode injection (e.g. timelapse) 
+// designed specifically for subsequent gcode injection (e.g. timelapse)
 std::string GCodeWriter::eager_lift(const LiftType type) {
+    const LiftType effective_type = type;
     std::string lift_move;
     double target_lift = 0;
     {
@@ -812,7 +850,7 @@ std::string GCodeWriter::eager_lift(const LiftType type) {
     }
 
     // BBS: spiral lift only safe with known position
-    if (type == LiftType::SpiralLift && this->is_current_position_clear()) {
+    if (effective_type == LiftType::SpiralLift && this->is_current_position_clear()) {
         double radius = target_lift / (2 * PI * atan(filament()->travel_slope()));
         // static spiral alignment when no move in x,y plane.
         // spiral centra is a radius distance to the right (y=0)
@@ -899,7 +937,10 @@ std::string GCodeWriter::travel_to_xyz(const Vec3d &point, const std::string &co
                 Vec2d temp = delta_no_z.normalized() * delta(2) / tan(this->filament()->travel_slope());
                 Vec3d slope_top_point = Vec3d(temp(0), temp(1), delta(2)) + source;
                 GCodeG1Formatter w0;
-                w0.emit_xyz(slope_top_point);
+                // A slope lift is a straight (linear) diagonal move, so remapping its
+                // endpoint is exact. Route the destination through apply_axis_remap()
+                // when a remap is active (no-op at identity).
+                w0.emit_xyz(has_axis_remap() ? apply_axis_remap(slope_top_point) : slope_top_point);
                 w0.emit_f(travel_speed * 60.0);
                 //BBS
                 w0.emit_comment(GCodeWriter::full_gcode_comment, comment);
@@ -913,7 +954,14 @@ std::string GCodeWriter::travel_to_xyz(const Vec3d &point, const std::string &co
         std::string xy_z_move;
         {
             GCodeG1Formatter w0;
-            if (this->is_current_position_clear()) {
+            if (has_axis_remap()) {
+                // Remap may couple XY with Z; emit full XYZ in machine coordinates.
+                w0.emit_xyz(apply_axis_remap(target));
+                w0.emit_f(travel_speed * 60.0);
+                w0.emit_comment(GCodeWriter::full_gcode_comment, comment);
+                xy_z_move = w0.string();
+            }
+            else if (this->is_current_position_clear()) {
                 w0.emit_xyz(target);
                 w0.emit_f(travel_speed * 60.0);
                 w0.emit_comment(GCodeWriter::full_gcode_comment, comment);
@@ -951,7 +999,13 @@ std::string GCodeWriter::travel_to_xyz(const Vec3d &point, const std::string &co
     Vec3d point_on_plate = { dest_point(0) - m_x_offset, dest_point(1) - m_y_offset, dest_point(2) };
     std::string out_string;
     GCodeG1Formatter w;
-    if (!this->is_current_position_clear())
+    if (has_axis_remap()) {
+        // Remap may couple XY with Z; emit full XYZ in machine coordinates.
+        w.emit_xyz(apply_axis_remap(point_on_plate));
+        w.emit_f(this->config.travel_speed.get_at(m_cached_extruder_idx) * 60.0);
+        w.emit_comment(GCodeWriter::full_gcode_comment, comment);
+        out_string = w.string();
+    } else if (!this->is_current_position_clear())
     {
         //force to move xy first then z after filament change
         w.emit_xy(Vec2d(point_on_plate.x(), point_on_plate.y()));
@@ -1001,7 +1055,13 @@ std::string GCodeWriter::_travel_to_z(double z, const std::string &comment)
     }
 
     GCodeG1Formatter w;
-    w.emit_z(z);
+    if (has_axis_remap()) {
+        // Remap may couple Z with other axes; emit full XYZ.
+        Vec3d machine = apply_axis_remap(Vec3d(m_pos.x() - m_x_offset, m_pos.y() - m_y_offset, z));
+        w.emit_xyz(machine);
+    } else {
+        w.emit_z(z);
+    }
     w.emit_f(speed * 60.0);
     //BBS
     w.emit_comment(GCodeWriter::full_gcode_comment, comment);
@@ -1010,6 +1070,14 @@ std::string GCodeWriter::_travel_to_z(double z, const std::string &comment)
 
 std::string GCodeWriter::_spiral_travel_to_z(double z, const Vec2d &ij_offset, const std::string &comment)
 {
+    // A circular XY arc / spiral lift cannot be correctly axis-remapped by
+    // transforming only its endpoint: the arc plane (G17/XY) and the I-J center
+    // would change under the remap. When an axis remap is active, fall back to a
+    // plain linear lift instead of emitting a possibly-wrong spiral/arc. This
+    // single guard covers every spiral call site (lazy/eager lift and travel_to_xyz).
+    if (has_axis_remap())
+        return _travel_to_z(z, comment);
+
     std::string output;
     double speed = this->config.travel_speed_z.get_at(m_cached_extruder_idx);
 
@@ -1109,7 +1177,12 @@ std::string GCodeWriter::extrude_to_xy(const Vec2d &point, double dE, const std:
     Vec2d point_on_plate = { point(0) - m_x_offset, point(1) - m_y_offset };
 
     GCodeG1Formatter w;
-    w.emit_xy(point_on_plate);
+    if (has_axis_remap()) {
+        Vec3d machine = apply_axis_remap(Vec3d(point_on_plate.x(), point_on_plate.y(), m_pos.z()));
+        w.emit_xyz(machine);
+    } else {
+        w.emit_xy(point_on_plate);
+    }
     if (!force_no_extrusion)
         w.emit_e(filament()->E());
     //BBS
@@ -1155,10 +1228,18 @@ std::string GCodeWriter::extrude_to_xyz(const Vec3d &point, double dE, const std
     Vec3d point_on_plate = { point(0) - m_x_offset, point(1) - m_y_offset, point(2) };
 
     GCodeG1Formatter w;
-    if (z_changed)
+    if (has_axis_remap()) {
+        // z_changed was computed from the ORIGINAL slicing Z, but an axis remap can
+        // make machine-Z depend on slicing X/Y. An X/Y-only move (slicing-Z
+        // unchanged) would then drop the required machine-Z word, so always emit
+        // full XYZ whenever a remap is active.
+        point_on_plate = apply_axis_remap(point_on_plate);
         w.emit_xyz(point_on_plate);
-    else
+    } else if (z_changed) {
+        w.emit_xyz(point_on_plate);
+    } else {
         w.emit_xy(Vec2d(point_on_plate.x(), point_on_plate.y()));
+    }
     if (!force_no_extrusion)
         w.emit_e(filament()->E());
     //BBS

src/libslic3r/GCodeWriter.hpp

@@ -9,11 +9,11 @@
 #include "Polygon.hpp"
 #include "PrintConfig.hpp"
 #include "GCode/CoolingBuffer.hpp"
-
 namespace Slic3r {
 
 class GCodeWriter {
 public:
+    virtual ~GCodeWriter() = default;
     GCodeConfig config;
     bool multiple_extruders;
 
@@ -78,23 +78,23 @@ public:
     std::string set_speed(double F, const std::string &comment = std::string(), const std::string &cooling_marker = std::string());
     // SoftFever NOTE: the returned speed is mm/minute
     double      get_current_speed() const { return m_current_speed;}
-    std::string travel_to_xy(const Vec2d &point, const std::string &comment = std::string());
+    virtual std::string travel_to_xy(const Vec2d &point, const std::string &comment = std::string());
-    std::string travel_to_xyz(const Vec3d &point, const std::string &comment = std::string(), bool force_z = false);
+    virtual std::string travel_to_xyz(const Vec3d &point, const std::string &comment = std::string(), bool force_z = false);
     std::string travel_to_z(double z, const std::string &comment = std::string(), bool force = false);
     bool        will_move_z(double z) const;
-    std::string extrude_to_xy(const Vec2d &point, double dE, const std::string &comment = std::string(), bool force_no_extrusion = false);
+    virtual std::string extrude_to_xy(const Vec2d &point, double dE, const std::string &comment = std::string(), bool force_no_extrusion = false);
     //BBS: generate G2 or G3 extrude which moves by arc
     std::string extrude_arc_to_xy(const Vec2d &point, const Vec2d &center_offset, double dE, const bool is_ccw, const std::string &comment = std::string(), bool force_no_extrusion = false);
-    std::string extrude_to_xyz(const Vec3d &point, double dE, const std::string &comment = std::string(), bool force_no_extrusion = false);
+    virtual std::string extrude_to_xyz(const Vec3d &point, double dE, const std::string &comment = std::string(), bool force_no_extrusion = false);
     std::string retract(bool before_wipe = false, double retract_length = 0);
     std::string retract_for_toolchange(bool before_wipe = false, double retract_length = 0);
     // extra_retract adds a small over-extrusion to the deretract move (PETG pre-extrusion).
     // Default 0 -> byte-identical to the plain deretract.
     std::string unretract(float extra_retract = 0.f);
     // do lift instantly
-    std::string eager_lift(const LiftType type);
+    virtual std::string eager_lift(const LiftType type);
     // record a lift request, do realy lift in next travel
-    std::string lazy_lift(LiftType lift_type = LiftType::NormalLift, bool spiral_vase = false);
+    virtual std::string lazy_lift(LiftType lift_type = LiftType::NormalLift, bool spiral_vase = false);
     std::string unlift();
     const Vec3d& get_position() const { return m_pos; }
     Vec3d&       get_position() { return m_pos; }
@@ -136,16 +136,48 @@ public:
     void invalidate_acceleration() { m_last_acceleration = 0; m_last_travel_acceleration = 0; }
     void invalidate_jerk() { m_last_jerk = 0; }
 
+    // Axis remap: permute/negate/reverse axes in G-code output.
+    // Works standalone (without belt mode) for printers with non-standard axis conventions.
+    void set_axis_remap(int rx, int ry, int rz);
+    void set_build_volume_max(const Vec3d &max);
+    bool has_axis_remap() const;
+
     // Returns whether this flavor supports separate print and travel acceleration.
     static bool supports_separate_travel_acceleration(GCodeFlavor flavor);
-  private:
+protected:
+    // Position/lift/offset state — accessible to subclasses (e.g. BeltGCodeWriter)
+    Vec3d           m_pos = Vec3d::Zero();
+    double          m_x_offset{ 0 };
+    double          m_y_offset{ 0 };
+    double          m_lifted;
+    double          m_to_lift;
+    LiftType        m_to_lift_type;
+    bool            m_is_first_layer = true;
+    bool            m_is_current_pos_clear = false;
+    double          m_current_speed;
+
+    virtual std::string _travel_to_z(double z, const std::string &comment);
+
+    // Axis remap state — accessible to subclasses.
+    int             m_remap_x = 0;  // RemapAxis: 0=+X, 1=+Y, 2=+Z, 3=-X, etc.
+    int             m_remap_y = 1;
+    int             m_remap_z = 2;
+    Vec3d           m_build_vol_max = Vec3d::Zero();
+
+    // Apply axis remap to a point. Returns pos unchanged if remap is identity.
+    Vec3d apply_axis_remap(const Vec3d &pos) const;
+
+    // Motion uses the global/base process variant until a filament becomes active.
+    // Protected so BeltGCodeWriter indexes the per-extruder speed options (travel_speed,
+    // travel_speed_z, initial_layer_travel_speed) exactly as the base writer does.
+    size_t     m_cached_extruder_idx;
+
+private:
 	// Extruders are sorted by their ID, so that binary search is possible.
     std::vector<Extruder> m_filament_extruders;
     bool            m_single_extruder_multi_material;
     std::vector<Extruder*> m_curr_filament_extruder;
     int        m_curr_extruder_id;
-    // Motion uses the global/base process variant until a filament becomes active.
-    size_t     m_cached_extruder_idx;
     unsigned int              m_last_acceleration;
     unsigned int              m_last_travel_acceleration;
     std::vector<unsigned int> m_max_travel_acceleration;
@@ -167,19 +199,6 @@ public:
     //BBS
     int             m_last_bed_temperature;
     bool            m_last_bed_temperature_reached;
-    double          m_lifted;
-
-    // BBS
-    double          m_to_lift;
-    LiftType        m_to_lift_type;
-    Vec3d           m_pos = Vec3d::Zero();
-    //BBS: this flag is used to indicate whether the m_pos is real.
-    //A example that of the first move, the m_pos is zero, but the real position of extruder doesn't
-    //Pos must be clear after the first xyz travel move
-    bool            m_is_current_pos_clear = false;
-    //BBS: x, y offset for gcode generated
-    double          m_x_offset{ 0 };
-    double          m_y_offset{ 0 };
 
     // Orca: slicing resolution in mm
     double          m_resolution = 0.01;
@@ -191,21 +210,18 @@ public:
     // non-rectangular beds such as delta/circular printers.
     Polygon              m_bed_printable_area;
     std::vector<Polygon> m_extruder_printable_areas;
-    
+
     std::string m_gcode_label_objects_start;
     std::string m_gcode_label_objects_end;
 
     //SoftFever
     bool            m_is_bbl_printers = false;
-    double          m_current_speed;
-    bool            m_is_first_layer = true;
 
     enum class Acceleration {
         Travel,
         Print
     };
 
-    std::string _travel_to_z(double z, const std::string &comment);
     std::string _spiral_travel_to_z(double z, const Vec2d &ij_offset, const std::string &comment);
     // Orca: printable area of the active extruder (per-extruder when configured, otherwise the bed). Null when unknown.
     const Polygon *active_printable_area() const;

src/libslic3r/Preset.cpp

@@ -1124,7 +1124,7 @@ static std::vector<std::string> s_Preset_print_options{
     "top_surface_speed", "support_speed", "support_object_xy_distance", "support_object_first_layer_gap", "support_interface_speed",
     "bridge_speed", "internal_bridge_speed", "gap_infill_speed", "travel_speed", "travel_speed_z", "initial_layer_speed",
     "outer_wall_acceleration", "initial_layer_acceleration", "top_surface_acceleration", "default_acceleration", "skirt_type", "skirt_loops", "skirt_speed","min_skirt_length", "skirt_distance", "skirt_start_angle", "skirt_height","single_loop_draft_shield", "draft_shield",
-    "brim_width", "brim_object_gap", "brim_flow_ratio", "brim_use_efc_outline", "combine_brims", "brim_type", "brim_ears_max_angle", "brim_ears_detection_length", "brim_ears_outer_only", "enable_support", "support_type", "support_threshold_angle", "support_threshold_overlap","enforce_support_layers",
+    "brim_width", "leading_brim_length", "extra_brim_width", "brim_object_gap", "brim_flow_ratio", "brim_use_efc_outline", "combine_brims", "brim_type", "brim_ears_max_angle", "brim_ears_detection_length", "brim_ears_outer_only", "enable_support", "support_type", "support_threshold_angle", "support_threshold_overlap","enforce_support_layers",
     "raft_layers", "raft_first_layer_density", "raft_first_layer_expansion", "raft_contact_distance", "raft_expansion",
     "support_base_pattern", "support_base_pattern_spacing", "support_expansion", "support_style",
     // BBS
@@ -1194,6 +1194,8 @@ static std::vector<std::string> s_Preset_print_options{
     "prime_volume",
     "prime_tower_infill_gap",
     "prime_tower_flat_ironing",
+    "belt_purge_tower_width",
+    "belt_purge_tower_object",
     "enable_tower_interface_features",
     "enable_tower_interface_cooldown_during_tower",
     "wipe_tower_no_sparse_layers",
@@ -1439,8 +1441,17 @@ static std::vector<std::string> s_Preset_machine_limits_options {
 
 static std::vector<std::string> s_Preset_printer_options {
     "printer_technology",
-    "printable_area", "extruder_printable_area", "support_parallel_printheads", "parallel_printheads_count", "parallel_printheads_bed_exclude_areas", "bed_exclude_area","bed_custom_texture", "bed_custom_model", "gcode_flavor",
+    "printable_area", "extruder_printable_area", "support_parallel_printheads", "parallel_printheads_count", "parallel_printheads_bed_exclude_areas", "bed_exclude_area","bed_custom_texture", "bed_custom_model", "build_plate_tilt_x", "build_plate_tilt_y", "belt_printer", "belt_printer_infinite_y",
-     "gcode_skip_config_block", "fan_kickstart", "part_cooling_fan_min_pwm", "fan_speedup_time", "fan_speedup_overhangs",
+    "belt_slice_rotation", "belt_slice_rotation_angle", "belt_slice_rotation_global",
+    "preslice_remap_x", "preslice_remap_y", "preslice_remap_z", "preslice_remap_global",
+    "gcode_remap_x", "gcode_remap_y", "gcode_remap_z", "gcode_back_transform",
+    "belt_frame_tilt_decouple", "belt_frame_tilt_angle",
+    "belt_preslice_global",
+    "first_layer_plane", "first_layer_plane_offset", "first_layer_plane_thickness",
+    "belt_support_floor_offset", "belt_support_floor_mode", "belt_support_z_offset_mode",
+    "enable_belt_purge_tower",
+    "gcode_flavor", "gcode_skip_config_block",
+    "fan_kickstart", "part_cooling_fan_min_pwm", "fan_speedup_time", "fan_speedup_overhangs",
     "single_extruder_multi_material", "manual_filament_change", "file_start_gcode", "machine_start_gcode", "machine_end_gcode", "before_layer_change_gcode", "printing_by_object_gcode", "layer_change_gcode", "time_lapse_gcode", "wrapping_detection_gcode", "change_filament_gcode", "change_extrusion_role_gcode",
     "printer_model", "printer_variant", "printer_extruder_id", "printer_extruder_variant", "extruder_variant_list", "default_nozzle_volume_type",
     "printable_height", "extruder_printable_height", "extruder_clearance_radius", "extruder_clearance_height_to_lid", "extruder_clearance_height_to_rod",

src/libslic3r/Print.cpp

@@ -18,6 +18,9 @@
 #include "Thread.hpp"
 #include "Time.hpp"
 #include "GCode.hpp"
+#include "BeltGCode.hpp"
+#include "BeltTransform.hpp"
+#include "GCode/MachineFrameTransform.hpp"
 #include "GCode/WipeTower.hpp"
 #include "GCode/WipeTower2.hpp"
 #include "GCode/WipeTowerEstimate.hpp"
@@ -26,6 +29,7 @@
 #include "MaterialType.hpp"
 #include "Model.hpp"
 #include "format.hpp"
+#include "LocalesUtils.hpp"
 #include <float.h>
 
 #include <algorithm>
@@ -111,6 +115,12 @@ bool Print::invalidate_state_by_config_options(const ConfigOptionResolver & /* n
     // Cache the plenty of parameters, which influence the G-code generator only,
     // or they are only notes not influencing the generated G-code.
     static std::unordered_set<std::string> steps_gcode = {
+        // Belt printer G-code axis remap (only affects G-code output, not slicing).
+        "gcode_remap_x",
+        "gcode_remap_y",
+        "gcode_remap_z",
+        // Machine-frame transform (derived from belt tilt; only affects G-code output).
+        "belt_frame_tilt_decouple", "belt_frame_tilt_angle",
         //BBS
         "additional_cooling_fan_speed",
         "reduce_crossing_wall",
@@ -310,8 +320,26 @@ bool Print::invalidate_state_by_config_options(const ConfigOptionResolver & /* n
             // Spiral Vase forces different kind of slicing than the normal model:
             // In Spiral Vase mode, holes are closed and only the largest area contour is kept at each layer.
             // Therefore toggling the Spiral Vase on / off requires complete reslicing.
-            || opt_key == "spiral_mode") {
+            || opt_key == "spiral_mode"
+            // Build plate tilt changes slicing plane orientation.
+            || opt_key == "build_plate_tilt_x"
+            || opt_key == "build_plate_tilt_y"
+            // Belt printer transform options change the mesh geometry before slicing.
+            || opt_key == "belt_printer"
+            || opt_key == "belt_slice_rotation"
+            || opt_key == "belt_slice_rotation_angle"
+            || opt_key == "belt_slice_rotation_global"
+            || opt_key == "belt_preslice_global"
+            || opt_key == "preslice_remap_global"
+            || opt_key == "preslice_remap_x"
+            || opt_key == "preslice_remap_y"
+            || opt_key == "preslice_remap_z") {
             osteps.emplace_back(posSlice);
+        } else if (
+               opt_key == "belt_support_floor_offset"
+            || opt_key == "belt_support_floor_mode"
+            || opt_key == "belt_support_z_offset_mode") {
+            osteps.emplace_back(posSupportMaterial);
         } else if (
                opt_key == "print_sequence"
             || opt_key == "filament_type"
@@ -346,6 +374,7 @@ bool Print::invalidate_state_by_config_options(const ConfigOptionResolver & /* n
             || opt_key == "hot_plate_temp"
             || opt_key == "textured_plate_temp"
             || opt_key == "enable_prime_tower"
+            || opt_key == "enable_belt_purge_tower"
             || opt_key == "enable_wrapping_detection"
             || opt_key == "prime_tower_enable_framework"
             || opt_key == "prime_tower_width"
@@ -377,6 +406,7 @@ bool Print::invalidate_state_by_config_options(const ConfigOptionResolver & /* n
             || opt_key == "prime_volume"
             || opt_key == "flush_into_infill"
             || opt_key == "flush_into_support"
+            || opt_key == "belt_purge_tower_width"
             || opt_key == "initial_layer_infill_speed"
             || opt_key == "travel_speed"
             || opt_key == "travel_speed_z"
@@ -608,6 +638,9 @@ std::vector<ObjectID> Print::print_object_ids() const
 
 bool Print::has_infinite_skirt() const
 {
+    // Belt printer: no skirt support.
+    if (m_config.belt_printer.value)
+        return false;
     // Orca: unclear why (m_config.ooze_prevention && this->extruders().size() > 1) logic is here, removed.
     // return (m_config.draft_shield == dsEnabled && m_config.skirt_loops > 0) || (m_config.ooze_prevention && this->extruders().size() > 1);
 
@@ -616,6 +649,9 @@ bool Print::has_infinite_skirt() const
 
 bool Print::has_skirt() const
 {
+    // Belt printer: no skirt support.
+    if (m_config.belt_printer.value)
+        return false;
     return (m_config.skirt_height > 0);
 }
 
@@ -624,6 +660,24 @@ bool Print::has_brim() const
     return std::any_of(m_objects.begin(), m_objects.end(), [](PrintObject *object) { return object->has_brim(); });
 }
 
+bool Print::has_tilted_belt() const
+{
+    if (! m_config.belt_printer.value)
+        return false;
+    // A Z rotation leaves the belt floor flat (BeltTransform forces shear = 0) and no
+    // rotation at all means the machine is geometrically a flat bed.
+    const BeltRotationAxis axis = m_config.belt_slice_rotation.value;
+    if (axis != BeltRotationAxis::X && axis != BeltRotationAxis::Y)
+        return false;
+    const double tilt = std::abs(m_config.belt_slice_rotation_angle.value);
+    return tilt >= BELT_BRIM_MIN_TILT_DEG && tilt <= BELT_BRIM_MAX_TILT_DEG;
+}
+
+bool Print::has_belt_brim() const
+{
+    return std::any_of(m_objects.begin(), m_objects.end(), [](PrintObject *object) { return object->has_belt_brim(); });
+}
+
 //BBS
 std::vector<size_t> Print::layers_sorted_for_object(float start, float end, std::vector<LayerPtrs> &layers_of_objects, std::vector<BoundingBox> &boundingBox_for_objects, VecOfPoints &objects_instances_shift)
 {
@@ -1353,6 +1407,84 @@ StringObjectException Print::validate(std::vector<StringObjectException> *warnin
     if (extruders.empty())
         return { L("No extrusions under current settings.") };
 
+    // Belt printer validation: incompatible features.
+    if (m_config.belt_printer.value) {
+        for (const PrintObject *object : m_objects) {
+            if (object->config().raft_layers > 0)
+                return { L("Raft is not compatible with belt printer mode.") };
+        }
+        if (m_config.draft_shield != dsDisabled)
+            return { L("Draft shield is not compatible with belt printer mode.") };
+
+        // Belt brim spans many layers and owns the layers below the object, which
+        // neither the prime tower nor spiral vase can share.
+        if (this->has_belt_brim()) {
+            if (m_config.enable_prime_tower.value)
+                return { L("Brim is not compatible with the prime tower on a belt printer. "
+                           "Disable one of them.") };
+            if (m_config.spiral_mode.value)
+                return { L("Brim is not compatible with spiral vase mode on a belt printer. "
+                           "Disable one of them.") };
+        }
+
+        for (const PrintObject *object : m_objects) {
+            const PrintObjectConfig &ocfg = object->config();
+            // Mirror PrintObject::has_belt_brim(): an inner-only brim needs a positive
+            // brim_width (leading/extra widen only the outer ring), so keep this
+            // predicate in step or the belt-brim warnings below would fire for a brim
+            // that has_belt_brim() rejects.
+            const bool wants_brim = ocfg.brim_type != btNoBrim
+                                 && (ocfg.brim_type == btInnerOnly
+                                         ? ocfg.brim_width.value > 0.
+                                         : (ocfg.brim_width.value > 0. || ocfg.leading_brim_length.value > 0.
+                                            || ocfg.extra_brim_width.value > 0.));
+            if (! wants_brim)
+                continue;
+
+            if (! this->has_tilted_belt()) {
+                if (std::abs(m_config.belt_slice_rotation_angle.value) > BELT_BRIM_MAX_TILT_DEG)
+                    warn(L("The belt is too steep for a brim, so no brim will be generated."),
+                         "brim_width", object->model_object());
+                else
+                    warn(L("A brim is only generated when the belt is tilted. Set a belt tilt angle, "
+                           "or remove the brim setting."),
+                         "brim_type", object->model_object());
+            }
+
+            if (ocfg.brim_type == btAutoBrim || ocfg.brim_type == btEar || ocfg.brim_type == btPainted)
+                warn(L("Belt printers support outer and inner brim only. Auto, Mouse ear and Painted "
+                       "brim are printed as Outer brim only, using Brim width."),
+                     "brim_type", object->model_object());
+
+            if (ocfg.leading_brim_length.value > 0. && ocfg.brim_object_gap.value > 0.)
+                warn(L("Brim-object gap separates the leading brim from the object's leading edge, "
+                       "which is the edge it is meant to anchor. Set the gap to 0 when using leading "
+                       "brim length."),
+                     "brim_object_gap", object->model_object());
+
+            // Unconditional: this suppresses the WHOLE belt brim, not just the apron, so a
+            // user asking for any brim at all needs to be told they are getting none.
+            if (! object->belt_brim_instances_compatible())
+                warn(L("This object's copies are spaced along the belt, so they would each need "
+                       "their own brim and none is generated. Print them as separate objects, or "
+                       "arrange the copies side by side across the belt."),
+                     "brim_type", object->model_object());
+        }
+        if (this->has_belt_brim() && m_objects.size() > 1)
+            warn(L("Leading brim length extends ahead of each object along the belt, and Arrange does "
+                   "not reserve that space. Leave room between objects."),
+                 "leading_brim_length");
+    } else {
+        // "Leading edge only" describes where a part meets a moving belt, so it has no
+        // meaning on a fixed bed.  Brim.cpp prints it as an ordinary outer brim rather
+        // than silently producing nothing; say so.
+        for (const PrintObject *object : m_objects)
+            if (object->config().brim_type == btLeadingEdgeOnly)
+                warn(L("\"Leading edge only\" brim applies to belt printers. On this printer it is "
+                       "printed as an ordinary outer brim."),
+                     "brim_type", object->model_object());
+    }
+
     // Orca: a gradient mixed filament only renders its gradient with "Mixed color sublayer" on;
     // without it ToolOrdering::resolve_mixed_filaments prints one whole component per layer and
     // the gradient is dropped silently. extruders() already covers painting, height ranges,
@@ -1408,6 +1540,25 @@ StringObjectException Print::validate(std::vector<StringObjectException> *warnin
             add_warning(layer_warning);
     }
 
+    if (m_config.belt_printer.value && m_config.enable_belt_purge_tower.value
+        && m_config.print_sequence == PrintSequence::ByObject
+        && extruders.size() > 1) {
+        StringObjectException warningtemp;
+        warningtemp.string     = L("The belt purge tower is not generated in \"By object\" print sequence; "
+                                   "filament changes will not be purged.");
+        warningtemp.opt_key    = "enable_belt_purge_tower";
+        warningtemp.is_warning = true;
+        add_warning(warningtemp);
+    }
+
+    if (m_config.belt_printer.value && m_config.enable_belt_purge_tower.value) {
+        const size_t prism_count = std::count_if(m_objects.begin(), m_objects.end(), [](const PrintObject *object) {
+            return object->config().belt_purge_tower_object.value;
+        });
+        if (prism_count > 1)
+            return {L("The project contains multiple managed belt purge towers. Reload the plate or toggle the belt purge tower off and on to regenerate it.")};
+    }
+
     if (m_config.enable_prime_tower) {
         for (const PrintObject* object : m_objects) {
             if (object->config().precise_z_height.value) {
@@ -1461,35 +1612,65 @@ StringObjectException Print::validate(std::vector<StringObjectException> *warnin
         return profile;
     };
 
-    // Checks that the print does not exceed the max print height
+    // Checks that the print does not exceed the max print height.
-    for (size_t print_object_idx = 0; print_object_idx < m_objects.size(); ++ print_object_idx) {
+    // For belt printers the slicing-frame Z spans the sheared X-length and
+    // is not comparable to printable_height (which is gantry clearance in the
+    // build-volume frame).  Compare against the model's pre-shear Z instead,
+    // mirroring the bbox computed in PrintObject::update_slicing_parameters.
+    // When the post-gcode MachineFrameTransform is active the printer's
+    // physical Z mapping is non-trivial — skip the check entirely.
+    const bool belt_printer = this->config().belt_printer.value;
+    bool skip_max_height_check = false;
+    if (belt_printer) {
+        MachineFrameTransform machine_frame;
+        machine_frame.init_from_config(this->config());
+        skip_max_height_check = machine_frame.is_active();
+    }
+    const double shrinkage_compensation_z = this->shrinkage_compensation().z();
+    for (size_t print_object_idx = 0; !skip_max_height_check && print_object_idx < m_objects.size(); ++ print_object_idx) {
         const PrintObject &print_object = *m_objects[print_object_idx];
-        //FIXME It is quite expensive to generate object layers just to get the print height!
-        if (auto layers = generate_object_layers(print_object.slicing_parameters(), layer_height_profile(print_object_idx), print_object.config().precise_z_height.value);
-            !layers.empty()) {
 
-            Vec3d test =this->shrinkage_compensation();
+        double effective_max_z       = 0;
-            const double shrinkage_compensation_z = this->shrinkage_compensation().z();
+        bool   last_layer_below_max  = false;
-            
+        bool   have_height           = false;
-            if (shrinkage_compensation_z != 1. && layers.back() > (this->config().printable_height / shrinkage_compensation_z + EPSILON)) {
+
-                // The object exceeds the maximum build volume height because of shrinkage compensation.
+        if (belt_printer) {
-                return StringObjectException{
+            double raw_z = print_object.model_object()->max_z();
-                    Slic3r::format(_u8L("While the object %1% itself fits the build volume, it exceeds the maximum build volume height because of material shrinkage compensation."), print_object.model_object()->name),
+            if (BeltTransformPipeline::has_preslice_remap(this->config()))
-                    print_object.model_object(),
+                raw_z = BeltTransformPipeline::remap_bbox(*print_object.model_object(), this->config()).size().z();
-                    ""
+            effective_max_z = raw_z;
-                };
+            have_height     = raw_z > 0;
-            } else if (layers.back() > this->config().printable_height + EPSILON) {
+        } else {
-                // Test whether the last slicing plane is below or above the print volume.
+            //FIXME It is quite expensive to generate object layers just to get the print height!
-                return StringObjectException{
+            auto layers = generate_object_layers(print_object.slicing_parameters(), layer_height_profile(print_object_idx), print_object.config().precise_z_height.value);
-                    0.5 * (layers[layers.size() - 2] + layers.back()) > this->config().printable_height + EPSILON ?
+            if (!layers.empty()) {
-                    Slic3r::format(_u8L("The object %1% exceeds the maximum build volume height."), print_object.model_object()->name) :
+                effective_max_z      = layers.back();
-                    Slic3r::format(_u8L("While the object %1% itself fits the build volume, its last layer exceeds the maximum build volume height."), print_object.model_object()->name) +
+                last_layer_below_max = layers.size() >= 2 &&
-                    " " + _u8L("You might want to reduce the size of your model or change current print settings and retry."),
+                    0.5 * (layers[layers.size() - 2] + layers.back()) <= this->config().printable_height + EPSILON;
-                    print_object.model_object(),
+                have_height          = true;
-                    ""
-                };
             }
         }
+
+        if (!have_height)
+            continue;
+
+        if (shrinkage_compensation_z != 1. && effective_max_z > (this->config().printable_height / shrinkage_compensation_z + EPSILON)) {
+            // The object exceeds the maximum build volume height because of shrinkage compensation.
+            return StringObjectException{
+                Slic3r::format(_u8L("While the object %1% itself fits the build volume, it exceeds the maximum build volume height because of material shrinkage compensation."), print_object.model_object()->name),
+                print_object.model_object(),
+                ""
+            };
+        } else if (effective_max_z > this->config().printable_height + EPSILON) {
+            return StringObjectException{
+                last_layer_below_max ?
+                Slic3r::format(_u8L("While the object %1% itself fits the build volume, its last layer exceeds the maximum build volume height."), print_object.model_object()->name) +
+                " " + _u8L("You might want to reduce the size of your model or change current print settings and retry.") :
+                Slic3r::format(_u8L("The object %1% exceeds the maximum build volume height."), print_object.model_object()->name),
+                print_object.model_object(),
+                ""
+            };
+        }
     }
 
     // Some of the objects has variable layer height applied by painting or by a table.
@@ -1509,12 +1690,12 @@ StringObjectException Print::validate(std::vector<StringObjectException> *warnin
                     return {_u8L("Variable layer height is not supported with Organic supports.") };
         }
 
-    if (this->has_wipe_tower() && ! m_objects.empty()) {
+    if ((this->has_wipe_tower() || this->has_belt_purge_tower()) && ! m_objects.empty()) {
         // Orca: wipe_tower_filament (issue #10971) is inserted into the tool order after
         // resolve_mixed_filaments has expanded every mixed (virtual) slot, so a mixed slot here
         // would reach the G-code as a tool change to a slot no nozzle carries. The GUI hides
         // mixed slots from the option; this guards loaded projects and the CLI.
-        if (m_config.wipe_tower_filament > 0) {
+        if (this->has_wipe_tower() && m_config.wipe_tower_filament > 0) {
             const auto  &is_mixed = m_config.filament_is_mixed.values;
             const size_t wipe_idx = size_t(m_config.wipe_tower_filament - 1);
             if (wipe_idx < is_mixed.size() && is_mixed[wipe_idx])
@@ -1536,12 +1717,17 @@ StringObjectException Print::validate(std::vector<StringObjectException> *warnin
                 }
         }
 
-        if (! m_config.use_relative_e_distances)
+        // The following two constraints come from the classic wipe tower G-code
-            return { L("The Wipe Tower is currently only supported with the relative extruder addressing (use_relative_e_distances=1).") };
+        // generator; purging into the belt purge prism uses normal object
+        // extrusions and does not need them.
+        if (this->has_wipe_tower()) {
+            if (! m_config.use_relative_e_distances)
+                return { L("The Wipe Tower is currently only supported with the relative extruder addressing (use_relative_e_distances=1).") };
+
+            if (m_config.ooze_prevention && m_config.single_extruder_multi_material)
+                return {L("Ooze prevention is only supported with the wipe tower when 'single_extruder_multi_material' is off.")};
+        }
 
-        if (m_config.ooze_prevention && m_config.single_extruder_multi_material)
-            return {L("Ooze prevention is only supported with the wipe tower when 'single_extruder_multi_material' is off.")};
-            
 #if 0
         if (m_config.gcode_flavor != gcfRepRapSprinter && m_config.gcode_flavor != gcfRepRapFirmware &&
             m_config.gcode_flavor != gcfRepetier && m_config.gcode_flavor != gcfMarlinLegacy && m_config.gcode_flavor != gcfMarlinFirmware)
@@ -2261,8 +2447,28 @@ BoundingBox PrintObject::get_first_layer_bbox(float& a, float& layer_height, std
             a += area(slice);
         }
     }
-    if (has_brim())
+    // Guard on `defined`: make_brim() can return before assigning this (it does on
+    // belt printers, where has_brim() is still true but the plate brim is skipped),
+    // and overwriting a valid bbox with an undefined one corrupted the first-layer
+    // centre and the GUI's first-layer area readout.
+    if (has_brim() && firstLayerObjectBrimBoundingBox.defined)
         bbox = firstLayerObjectBrimBoundingBox;
+    // Belt brim: the apron reaches ahead of the object along the belt.
+    if (has_belt_brim()) {
+        const Point shift = instances().empty() ? Point(0, 0) : instances()[0].shift_without_plate_offset();
+        for (const ExPolygons &areas : m_belt_brim_areas_by_layer)
+            for (const ExPolygon &ex : areas) {
+                BoundingBox bb = get_extents(ex.contour);
+                bb.translate(shift.x(), shift.y());
+                bbox.merge(bb);
+            }
+        for (const BeltBrimBand &band : m_belt_brim_prologue)
+            for (const ExPolygon &ex : band.areas) {
+                BoundingBox bb = get_extents(ex.contour);
+                bb.translate(shift.x(), shift.y());
+                bbox.merge(bb);
+            }
+    }
     return bbox;
 }
 
@@ -2361,15 +2567,24 @@ void Print::process(long long *time_cost_with_cache, bool use_cache)
     int object_count = m_objects.size();
     std::set<PrintObject*> need_slicing_objects;
     std::set<PrintObject*> re_slicing_objects;
+    // Belt global modes couple each object's bed position into its layer Z values,
+    // so sharing layers between "identical" objects is wrong.
+    bool belt_no_share = m_config.belt_printer.value &&
+        ((m_config.belt_slice_rotation_global.value
+              && m_config.belt_slice_rotation.value != BeltRotationAxis::None)
+         || m_config.preslice_remap_global.value
+         || m_config.belt_preslice_global.value);
     if (!use_cache) {
         for (int index = 0; index < object_count; index++)
         {
             PrintObject *obj =  m_objects[index];
-            for (PrintObject *slicing_obj : need_slicing_objects)
+            if (!belt_no_share) {
-            {
+                for (PrintObject *slicing_obj : need_slicing_objects)
-                if (is_print_object_the_same(obj, slicing_obj)) {
+                {
-                    obj->set_shared_object(slicing_obj);
+                    if (is_print_object_the_same(obj, slicing_obj)) {
-                    break;
+                        obj->set_shared_object(slicing_obj);
+                        break;
+                    }
                 }
             }
             if (!obj->get_shared_object())
@@ -2388,12 +2603,14 @@ void Print::process(long long *time_cost_with_cache, bool use_cache)
             PrintObject *obj =  m_objects[index];
             bool found_shared = false;
             if (need_slicing_objects.find(obj) == need_slicing_objects.end()) {
-                for (PrintObject *slicing_obj : need_slicing_objects)
+                if (!belt_no_share) {
-                {
+                    for (PrintObject *slicing_obj : need_slicing_objects)
-                    if (is_print_object_the_same(obj, slicing_obj)) {
+                    {
-                        obj->set_shared_object(slicing_obj);
+                        if (is_print_object_the_same(obj, slicing_obj)) {
-                        found_shared = true;
+                            obj->set_shared_object(slicing_obj);
-                        break;
+                            found_shared = true;
+                            break;
+                        }
                     }
                 }
                 if (!found_shared) {
@@ -2601,7 +2818,10 @@ void Print::process(long long *time_cost_with_cache, bool use_cache)
 
         m_wipe_tower_data.clear();
         m_tool_ordering.clear();
-        if (this->has_wipe_tower()) {
+        if (this->has_belt_purge_tower() && this->config().print_sequence != PrintSequence::ByObject) {
+            this->_plan_belt_purge();
+        }
+        else if (this->has_wipe_tower()) {
             this->_make_wipe_tower();
         }
         else if (this->config().print_sequence != PrintSequence::ByObject) {
@@ -2849,6 +3069,26 @@ void Print::process(long long *time_cost_with_cache, bool use_cache)
         }
 
 
+        // Belt brim: bound the first-layer convex hull by the lowest apron band, so
+        // bed levelling and the initial purge line account for brim that reaches
+        // ahead of every object.
+        if (this->has_belt_brim()) {
+            for (PrintObject *object : m_objects) {
+                if (! object->has_belt_brim() || object->belt_brim_prologue().empty())
+                    continue;
+                const BeltBrimBand &lowest = object->belt_brim_prologue().front();
+                for (const PrintInstance &instance : object->instances())
+                    for (const ExPolygon &ex : lowest.areas) {
+                        Polygon poly = ex.contour;
+                        poly.translate(instance.shift);
+                        append(m_first_layer_convex_hull.points, std::move(poly.points));
+                    }
+            }
+        }
+
+        // Unchanged for belt printers: _make_skirt() already returns early for them, and
+        // the belt brim does not populate m_brimMapByInstance, which is what the
+        // skirt/brim grouping reads.
         if (has_skirt() || has_infinite_skirt() || has_brim()) {
             // Generate skirt/brim groups after brim so per-object and draft-shield footprints
             // include brims when grouping and offsetting skirt loops.
@@ -2943,12 +3183,17 @@ std::string Print::export_gcode(const std::string& path_template, GCodeProcessor
     this->set_status(80, message);
 
     // The following line may die for multiple reasons.
-    GCode gcode;
+    // Factory: use BeltGCode for belt printers, plain GCode otherwise.
+    std::unique_ptr<GCode> gcode;
+    if (m_config.belt_printer.value)
+        gcode = std::make_unique<BeltGCode>();
+    else
+        gcode = std::make_unique<GCode>();
     //BBS: compute plate offset for gcode-generator
     const Vec3d origin = this->get_plate_origin();
-    gcode.set_gcode_offset(origin(0), origin(1));
+    gcode->set_gcode_offset(origin(0), origin(1));
-    gcode.do_export(this, path.c_str(), result, thumbnail_cb);
+    gcode->do_export(this, path.c_str(), result, thumbnail_cb);
-    gcode.export_layer_filaments(result);
+    gcode->export_layer_filaments(result);
     //BBS
     if (result != nullptr) {
         result->conflict_result = m_conflict_result;
@@ -2963,6 +3208,10 @@ std::string Print::export_gcode(const std::string& path_template, GCodeProcessor
 
 void Print::_make_skirt()
 {
+    // Belt printer: skirt is not compatible.
+    if (m_config.belt_printer.value)
+        return;
+  
     const bool generate_skirt = this->has_skirt() || this->has_infinite_skirt();
 
     // First off we need to decide how tall the skirt must be.
@@ -4003,6 +4252,13 @@ int Print::get_config_index(int filament_id, int layer_id, const std::vector<std
 // Wipe tower support.
 bool Print::has_wipe_tower() const
 {
+    // Belt printers never get the classic wipe tower: its G-code is generated
+    // directly in machine XY coordinates and bypasses the belt rotation
+    // transform. Purging is routed into the belt purge prism instead
+    // (see has_belt_purge_tower() / _plan_belt_purge()).
+    if (m_config.belt_printer.value)
+        return false;
+
     if (m_config.enable_prime_tower.value == true) {
         if (m_config.enable_wrapping_detection.value && m_config.wrapping_exclude_area.values.size() > 2)
             return true;
@@ -4015,6 +4271,7 @@ bool Print::has_wipe_tower() const
     return false;
 }
 
+
 const WipeTowerData &Print::wipe_tower_data(size_t filaments_cnt) const
 {
     // Until the tower is generated, size it with the estimate the GUI/CLI placement uses, so
@@ -4044,6 +4301,7 @@ bool Print::enable_timelapse_print() const
     return m_config.timelapse_type.value == TimelapseType::tlSmooth;
 }
 
+
 void Print::_make_wipe_tower()
 {
     m_wipe_tower_data.clear();

src/libslic3r/Print.hpp

@@ -17,6 +17,8 @@
 #include "GCode/ThumbnailData.hpp"
 #include "GCode/GCodeProcessor.hpp"
 #include "MultiMaterialSegmentation.hpp"
+#include "BeltBrim.hpp"
+#include "BeltTransform.hpp"
 #include "ObjectID.hpp"
 #include "libslic3r.h"
 
@@ -205,6 +207,13 @@ class ConstSupportLayerPtrsAdaptor : public ConstVectorOfPtrsAdaptor<SupportLaye
     ConstSupportLayerPtrsAdaptor(const SupportLayerPtrs *data) : ConstVectorOfPtrsAdaptor<SupportLayer>(data) {}
 };
 
+// Returns the model's raw bounding box with pre-slice axis remap applied.
+// When no remap is active, returns the unmodified raw_bounding_box().
+inline BoundingBoxf3 belt_remapped_bbox(const ModelObject &model_object, const PrintConfig &config)
+{
+    return BeltTransformPipeline::remap_bbox(model_object, config);
+}
+
 // Single instance of a PrintObject.
 // As multiple PrintObjects may be generated for a single ModelObject (their instances differ in rotation around Z),
 // ModelObject's instancess will be distributed among these multiple PrintObjects.
@@ -389,6 +398,30 @@ public:
             && ! this->has_raft();
     }
 
+    // Belt brim.  A tilted belt needs its brim laid onto the belt plane over many
+    // layers instead of as one flat first-layer ring, so it is generated by
+    // BeltBrim.cpp and stored per layer here.  Deliberately separate from
+    // has_brim(): that predicate feeds PrintRegion extruder collection, support
+    // trimming and the spiral vase probe, and widening it would perturb belt
+    // support output.
+    bool                         has_belt_brim() const;
+    // Brim filament for this object's belt brim, returned in the 1-based domain of
+    // PrintRegion::outer_wall_filament_id and the raw values pushed into
+    // LayerTools::extruders in ToolOrdering::collect_extruders (ToolOrdering reindexes
+    // the whole list to 0-based afterwards).  Lowest positive outer_wall_filament_id
+    // over the printing regions, 1 if none is explicitly set.
+    unsigned int                 belt_brim_filament() const;
+    // False when this object's instances sit at different points ALONG the belt, which
+    // would need a separate set of bands each.  Public so validate() can explain it.
+    bool                         belt_brim_instances_compatible() const;
+    const std::vector<ExtrusionEntityCollection>& belt_brim_by_layer()       const { return m_belt_brim_by_layer; }
+    const std::vector<ExPolygons>&                belt_brim_areas_by_layer() const { return m_belt_brim_areas_by_layer; }
+    const std::vector<BeltBrimBand>&              belt_brim_prologue()       const { return m_belt_brim_prologue; }
+    void                         clear_belt_brim();
+    void                         set_belt_brim(std::vector<ExtrusionEntityCollection> &&by_layer,
+                                               std::vector<ExPolygons>                &&areas,
+                                               std::vector<BeltBrimBand>              &&prologue);
+
     // BBS
     const ExtrusionEntityCollection& object_skirt() const {
         return m_skirt;
@@ -538,6 +571,17 @@ private:
     std::vector<std::set<int>> detect_extruder_geometric_unprintables() const;
 
     void slice_volumes();
+    // Belt mode: shift the sliced layer grid (layer print_z and the belt floor
+    // clipping shift) by delta, used by Print::_align_belt_purge_layers() to
+    // snap the purge prism's layers onto the printed objects' layer grid.
+    void belt_shift_layer_grid(double delta);
+    // Belt mode: remove layers above z (cancel the purge prism past the last
+    // toolchange). Returns how many layers were dropped.
+    size_t belt_truncate_layers_above(coordf_t z);
+    // Restore layers removed by belt_truncate_layers_above() before replanning.
+    // Wipe-tower-only invalidations do not necessarily reslice the object, so
+    // truncation must be reversible when later toolchanges move upward.
+    void belt_restore_truncated_layers();
     //BBS
     ExPolygons _shrink_contour_holes(double contour_delta, double hole_delta, const ExPolygons& polys) const;
     // BBS
@@ -580,7 +624,14 @@ private:
 
     SlicingParameters                       m_slicing_params;
     LayerPtrs                               m_layers;
+    LayerPtrs                               m_belt_truncated_layers;
     SupportLayerPtrs                        m_support_layers;
+    // Belt brim, generated in posSupportMaterial by BeltBrim.cpp.  Object-local
+    // slicing frame, one entry per object layer plus a prologue of brim-only
+    // bands that print below the object's first layer.
+    std::vector<ExtrusionEntityCollection>  m_belt_brim_by_layer;
+    std::vector<ExPolygons>                 m_belt_brim_areas_by_layer;
+    std::vector<BeltBrimBand>               m_belt_brim_prologue;
     // BBS
     std::shared_ptr<TreeSupportData>        m_tree_support_preview_cache;
 
@@ -599,7 +650,27 @@ private:
 
     PrintObject*                            m_shared_object{ nullptr };
 
-    
+    // Belt printer: global Z offset applied to this object's layers for shear positioning.
+    double                                  m_belt_global_z_offset { 0.0 };
+    // Belt printer: min_z of mesh after belt shear (before Z-shift), for z_offset calc.
+    double                                  m_belt_min_z { 0.0 };
+    // Belt printer: XY correction from global pre-slice mode, applied to G-code origin.
+    Vec2d                                   m_belt_global_xy_correction { Vec2d::Zero() };
+    // Belt printer: exact belt_floor_z_shift computed during posSlice from a
+    // vertex-level scan of the post-transform mesh.  Cached separately from
+    // m_slicing_params so that rebuilding m_slicing_params on a non-belt-affecting
+    // invalidation (e.g. support config change) doesn't replace the exact value
+    // with the bbox approximation seeded by create_from_config().  Cleared when
+    // posSlice is invalidated.
+    double                                  m_belt_floor_z_shift_cached { 0.0 };
+    bool                                    m_belt_floor_z_shift_cache_valid { false };
+public:
+    double belt_global_z_offset() const { return m_belt_global_z_offset; }
+    double belt_min_z() const { return m_belt_min_z; }
+    Vec2d  belt_global_xy_correction() const { return m_belt_global_xy_correction; }
+private:
+
+
     // SoftFever
     // 
     // object id
@@ -960,6 +1031,15 @@ public:
     bool                has_infinite_skirt() const;
     bool                has_skirt() const;
     bool                has_brim() const;
+    // True when the belt is tilted enough that the BELT plane, not the bed plane, is
+    // the adhesion surface.  The flat plate brim is geometrically meaningless then
+    // and must not run, whatever the per-object brim settings say - in particular
+    // brim_type "Auto", which has_brim() reports as enabled even at width 0.
+    bool                has_tilted_belt() const;
+    // True when at least one object actually gets a tilted-belt brim generated.
+    // Implies has_tilted_belt(), but additionally requires the object's own brim
+    // settings to ask for one.
+    bool                has_belt_brim() const;
     //BBS
     bool                has_auto_brim() const    {
         return std::any_of(m_objects.begin(), m_objects.end(), [](PrintObject* object) { return object->config().brim_type == btAutoBrim; });
@@ -1034,6 +1114,8 @@ public:
 
     // Wipe tower support.
     bool                        has_wipe_tower() const;
+    // Belt purge prism (belt-mode replacement for the wipe tower).
+    bool                        has_belt_purge_tower() const;
     const WipeTowerData&        wipe_tower_data(size_t filaments_cnt = 0) const;
     const ToolOrdering& 		tool_ordering() const { return m_tool_ordering; }
 
@@ -1283,6 +1365,12 @@ private:
 
     void                _make_skirt();
     void                _make_wipe_tower();
+    // Belt mode: route filament-change purging into the belt purge prism
+    // (flush-into-objects) without generating a classic wipe tower.
+    void                _plan_belt_purge();
+    // Belt mode: shift the purge prism's layer grid to match the printed
+    // objects' grid so toolchange layers find prism layers to purge into.
+    void                _align_belt_purge_layers();
     void                finalize_first_layer_convex_hull();
     void                update_filament_self_index_cache();
     // Deduplicates, per filament, the (extruder type x volume type) variants the grouping

src/libslic3r/PrintApply.cpp

@@ -1,6 +1,7 @@
 #include "ClipperUtils.hpp"
 #include "Model.hpp"
 #include "Print.hpp"
+#include "BeltTransform.hpp"
 #include "FilamentMixer.hpp"
 
 #include <boost/log/trivial.hpp>
@@ -136,22 +137,29 @@ struct PrintObjectTrafoAndInstances
 
 // Generate a list of trafos and XY offsets for instances of a ModelObject
 // Orca: Updated to include XYZ filament shrinkage compensation
-static std::vector<PrintObjectTrafoAndInstances> print_objects_from_model_object(const ModelObject &model_object, const Vec3d &shrinkage_compensation)
+static std::vector<PrintObjectTrafoAndInstances> print_objects_from_model_object(const ModelObject &model_object, const Vec3d &shrinkage_compensation, bool force_separate_instances = false)
 {
     std::set<PrintObjectTrafoAndInstances> trafos;
     PrintObjectTrafoAndInstances           trafo;
     //BBS: add useful logs for debug
     int index = 0;
+    int unique_counter = 0;
     for (ModelInstance *model_instance : model_object.instances) {
         if (model_instance->is_printable()) {
             // Orca: Updated with XYZ filament shrinkage compensation
             Geometry::Transformation model_instance_transformation = model_instance->get_transformation();
             trafo.trafo = model_instance_transformation.get_matrix_with_applied_shrinkage_compensation(shrinkage_compensation);
-            
+
             auto shift = Point::new_scale(trafo.trafo.data()[12], trafo.trafo.data()[13]);
             // Reset the XY axes of the transformation.
             trafo.trafo.data()[12] = 0;
             trafo.trafo.data()[13] = 0;
+            // Belt printer global mode: prevent instance grouping so each
+            // copy gets its own PrintObject with independent layer Z values.
+            // Add a tiny unique perturbation to the existing Z (don't replace
+            // it — the Z translation from ensure_on_bed must be preserved).
+            if (force_separate_instances)
+                trafo.trafo.data()[14] += 1e-10 * (++unique_counter);
             // Search or insert a trafo.
             auto it = trafos.emplace(trafo).first;
             const_cast<PrintObjectTrafoAndInstances&>(*it).instances.emplace_back(PrintInstance{ nullptr, model_instance, shift });
@@ -1748,11 +1756,20 @@ Print::ApplyStatus Print::apply(const Model &model, DynamicPrintConfig new_full_
         PrintObjectPtrs print_objects_new;
         print_objects_new.reserve(std::max(m_objects.size(), m_model.objects.size()));
         bool new_objects = false;
+        bool belt_instances_shifted = false;
         // Walk over all new model objects and check, whether there are matching PrintObjects.
         for (ModelObject *model_object : m_model.objects) {
             ModelObjectStatus &model_object_status = const_cast<ModelObjectStatus&>(model_object_status_db.reuse(*model_object));
             // Orca: Updated for XYZ filament shrink compensation
-            model_object_status.print_instances = print_objects_from_model_object(*model_object, this->shrinkage_compensation());
+            // Belt global mode: force each instance into its own PrintObject
+            // so each gets independent layer Z values.
+            bool belt_force_separate = m_config.belt_printer.value && (
+                (m_config.belt_slice_rotation_global.value
+                    && m_config.belt_slice_rotation.value != BeltRotationAxis::None
+                    && std::abs(m_config.belt_slice_rotation_angle.value) > EPSILON)
+                || m_config.belt_preslice_global.value
+                || (m_config.preslice_remap_global.value && BeltTransformPipeline::has_preslice_remap(m_config)));
+            model_object_status.print_instances = print_objects_from_model_object(*model_object, this->shrinkage_compensation(), belt_force_separate);
             std::vector<const PrintObjectStatus*> old;
             old.reserve(print_object_status_db.count(*model_object));
             for (const PrintObjectStatus &print_object_status : print_object_status_db.get_range(*model_object))
@@ -1800,6 +1817,7 @@ Print::ApplyStatus Print::apply(const Model &model, DynamicPrintConfig new_full_
                     if (status != PrintBase::APPLY_STATUS_UNCHANGED) {
                         size_t extruder_num = new_full_config.option<ConfigOptionFloats>("nozzle_diameter")->size();
                         update_apply_status(status == PrintBase::APPLY_STATUS_INVALIDATED);
+                        belt_instances_shifted = true;
                     }
 					print_objects_new.emplace_back((*it_old)->print_object);
 					const_cast<PrintObjectStatus*>(*it_old)->status = PrintObjectStatus::Reused;
@@ -1835,6 +1853,20 @@ Print::ApplyStatus Print::apply(const Model &model, DynamicPrintConfig new_full_
                 update_apply_status(object->invalidate_step(posSlice));
             }
         }
+
+        // Belt printer global mode: when any object's instances shifted,
+        // recompute m_belt_global_z_offset for ALL objects (it depends on
+        // min_shift across all objects, so one move affects everyone).
+        if (belt_instances_shifted
+            && m_config.belt_printer.value
+            && ((m_config.belt_slice_rotation_global.value
+                    && m_config.belt_slice_rotation.value != BeltRotationAxis::None
+                    && std::abs(m_config.belt_slice_rotation_angle.value) > EPSILON)
+                || m_config.belt_preslice_global.value
+                || (m_config.preslice_remap_global.value && BeltTransformPipeline::has_preslice_remap(m_config)))) {
+            for (PrintObject *object : m_objects)
+                update_apply_status(object->invalidate_step(posSlice));
+        }
     }
 
     //BBS: check the config again

src/libslic3r/PrintConfig.cpp

@@ -1,7 +1,9 @@
 #include "PrintConfig.hpp"
 #include "PrintConfigConstants.hpp"
+#include "BeltTransform.hpp"
 #include "ClipperUtils.hpp"
 #include "Config.hpp"
+#include "Geometry.hpp"
 #include "FilamentMixer.hpp"
 #include "MaterialType.hpp"
 #include "I18N.hpp"
@@ -347,6 +349,54 @@ static t_config_enum_values s_keys_map_SlicingMode {
 };
 CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(SlicingMode)
 
+static t_config_enum_values s_keys_map_BeltRotationAxis {
+    { "none", int(BeltRotationAxis::None) },
+    { "x",    int(BeltRotationAxis::X) },
+    { "y",    int(BeltRotationAxis::Y) },
+    { "z",    int(BeltRotationAxis::Z) },
+};
+CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(BeltRotationAxis)
+
+static t_config_enum_values s_keys_map_RemapAxis {
+    { "pos_x", int(RemapAxis::PosX) },
+    { "pos_y", int(RemapAxis::PosY) },
+    { "pos_z", int(RemapAxis::PosZ) },
+    { "neg_x", int(RemapAxis::NegX) },
+    { "neg_y", int(RemapAxis::NegY) },
+    { "neg_z", int(RemapAxis::NegZ) },
+    { "rev_x", int(RemapAxis::RevX) },
+    { "rev_y", int(RemapAxis::RevY) },
+    { "rev_z", int(RemapAxis::RevZ) },
+};
+CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(RemapAxis)
+
+static t_config_enum_values s_keys_map_BeltSupportFloorMode {
+    { "none",           int(BeltSupportFloorMode::None) },
+    { "generator_only", int(BeltSupportFloorMode::GeneratorOnly) },
+    { "clip_only",      int(BeltSupportFloorMode::ClipOnly) },
+    { "both",           int(BeltSupportFloorMode::Both) },
+};
+CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(BeltSupportFloorMode)
+
+static t_config_enum_values s_keys_map_BeltSupportZOffsetMode {
+    { "none",           int(BeltSupportZOffsetMode::None) },
+    { "unconditional",  int(BeltSupportZOffsetMode::Unconditional) },
+    { "raft_only",      int(BeltSupportZOffsetMode::RaftOnly) },
+};
+CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(BeltSupportZOffsetMode)
+
+static t_config_enum_values s_keys_map_FirstLayerPlaneMode {
+    { "auto",        int(FirstLayerPlaneMode::Auto) },
+    { "xy",          int(FirstLayerPlaneMode::XY) },
+    { "yz",          int(FirstLayerPlaneMode::YZ) },
+    { "xz",          int(FirstLayerPlaneMode::XZ) },
+    { "belt_affine", int(FirstLayerPlaneMode::BeltAffine) },
+    // Back-compat alias: pre-rotation builds serialised this mode as
+    // "belt_shear".  Accept it on parse so old 3MFs / presets keep loading.
+    { "belt_shear",  int(FirstLayerPlaneMode::BeltAffine) },
+};
+CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(FirstLayerPlaneMode)
+
 static t_config_enum_values s_keys_map_SupportMaterialPattern {
     { "rectilinear",        smpRectilinear },
     { "rectilinear-grid",   smpRectilinearGrid },
@@ -463,6 +513,7 @@ static const t_config_enum_values s_keys_map_BrimType = {
     {"auto_brim", btAutoBrim},  // BBS
     {"brim_ears", btEar},     // Orca
     {"painted", btPainted},  // BBS
+    {"leading_edge_only", btLeadingEdgeOnly},  // belt printers
 };
 CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(BrimType)
 
@@ -1853,6 +1904,45 @@ void PrintConfigDef::init_fff_params()
     def->mode = comSimple;
     def->set_default_value(new ConfigOptionFloat(0.));
 
+    def = this->add("leading_brim_length", coFloat);
+    def->label = L("Leading brim length");
+    def->category = L("Support");
+    def->tooltip = L("Belt printers only. Extends the brim AHEAD of the object along the belt, on "
+                     "every downhill-facing edge of its contact area - both the object's first "
+                     "contact with the belt and any island that lands later. This apron is laid "
+                     "onto the belt before the object reaches it, so the leading edge has "
+                     "something already stuck down to hold on to.\n\n"
+                     "Measured on the belt surface, and added on top of Brim width: the brim "
+                     "reaches Brim-object gap + Leading brim length + Brim width ahead of the "
+                     "object. Set Brim-object gap to 0, or the apron will not touch the object it "
+                     "is meant to anchor.\n\n"
+                     "On a tilted belt each layer lays one strip of the brim, so the thickness of "
+                     "the resulting brim sheet is set by flow rather than by layer height. Use "
+                     "Brim flow ratio to tune it.\n\n"
+                     "Set to 0 to disable.");
+    def->sidetext = L("mm");	// millimeters, CIS languages need translation
+    def->min = 0;
+    def->max = 100;
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionFloat(0.));
+
+    def = this->add("extra_brim_width", coFloat);
+    def->label = L("Extra brim width");
+    def->category = L("Support");
+    def->tooltip = L("Belt printers only. Widens the brim SIDEWAYS, across the belt, without "
+                     "extending it further ahead of or behind the object. Use it when a part needs "
+                     "more grip along its length than Brim width alone gives.\n\n"
+                     "Measured on the belt surface, and added on top of Brim width: the brim "
+                     "reaches Brim-object gap + Brim width + Extra brim width to either side of "
+                     "the object. To extend the brim ahead of the object instead, use Leading brim "
+                     "length.\n\n"
+                     "Set to 0 to disable.");
+    def->sidetext = L("mm");	// millimeters, CIS languages need translation
+    def->min = 0;
+    def->max = 100;
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionFloat(0.));
+
     def = this->add("brim_type", coEnum);
     def->label = L("Brim type");
     def->category = L("Support");
@@ -1866,6 +1956,7 @@ void PrintConfigDef::init_fff_params()
     def->enum_values.emplace_back("inner_only");
     def->enum_values.emplace_back("outer_and_inner");
     def->enum_values.emplace_back("no_brim");
+    def->enum_values.emplace_back("leading_edge_only");
     def->enum_labels.emplace_back(L("Auto"));
     def->enum_labels.emplace_back(L("Mouse ear"));
     def->enum_labels.emplace_back(L("Painted"));
@@ -1873,6 +1964,7 @@ void PrintConfigDef::init_fff_params()
     def->enum_labels.emplace_back(L("Inner brim only"));
     def->enum_labels.emplace_back(L("Outer and inner brim"));
     def->enum_labels.emplace_back(L("No-brim"));
+    def->enum_labels.emplace_back(L("Leading edge only"));
     def->mode = comSimple;
     def->set_default_value(new ConfigOptionEnum<BrimType>(btAutoBrim));
 
@@ -7063,6 +7155,297 @@ void PrintConfigDef::init_fff_params()
     def->mode = comSimple;
     def->set_default_value(new ConfigOptionFloatOrPercent(50., true));
 
+    def = this->add("build_plate_tilt_x", coFloat);
+    def->label = L("Build plate tilt X");
+    def->category = L("Support");
+    def->tooltip = L("Tilt angle of the build plate along the X axis. "
+                     "A positive value tilts the plate so the +X side is higher, shifting gravity toward -X and increasing overhangs on the +X side. "
+                     "A negative value tilts the -X side higher. Set to 0 for no X-axis tilt. "
+                     "In belt printer mode, this is automatically synced to the belt angle.");
+    def->sidetext = u8"\u00B0";
+    def->min = -90;
+    def->max = 90;
+    def->mode = comExpert;
+    def->set_default_value(new ConfigOptionFloat(0.));
+
+    def = this->add("build_plate_tilt_y", coFloat);
+    def->label = L("Build plate tilt Y");
+    def->category = L("Support");
+    def->tooltip = L("Tilt angle of the build plate along the Y axis. "
+                     "A positive value tilts the plate so the +Y side is higher, shifting gravity toward -Y and increasing overhangs on the +Y side. "
+                     "A negative value tilts the -Y side higher. Set to 0 for no Y-axis tilt.");
+    def->sidetext = u8"\u00B0";
+    def->min = -90;
+    def->max = 90;
+    def->mode = comExpert;
+    def->set_default_value(new ConfigOptionFloat(0.));
+
+    def = this->add("belt_printer", coBool);
+    def->label = L("Enable belt printing");
+    def->category = L("Printable space");
+    def->tooltip = L("Enable belt printer mode. Belt printers use a conveyor belt as the build surface, "
+                     "tilted at an angle (typically 45 degrees). The slicer will rotate the slicing plane "
+                     "and transform G-code coordinates for the tilted build surface.");
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionBool(false));
+
+    def = this->add("belt_printer_infinite_y", coBool);
+    def->label = L("Infinite Y axis");
+    def->category = L("Printable space");
+    def->tooltip = L("Enable infinite Y axis for belt printers. "
+                     "When enabled, the Y axis build volume limit is effectively removed, "
+                     "allowing objects of any length to be printed along the belt direction.");
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionBool(true));
+
+    // Mesh rotation applied before slicing — the sole mesh-side belt transform AND
+    // the single source of truth for the physical belt tilt (bed rendering, support
+    // gravity tilt and bed-exclusion projection all derive their angle from this).
+    def = this->add("belt_slice_rotation", coEnum);
+    def->label = L("Belt tilt axis");
+    def->category = L("Printable space");
+    def->tooltip = L("Axis the mesh is rotated about before slicing. This is the belt "
+                     "printer's tilt: an isometric (no distortion) rotation that also "
+                     "drives bed rendering and support gravity tilt, and that the g-code "
+                     "back-transform inverts before the machine-frame shear/scale and remap. "
+                     "X is the typical gantry tilt (belt travels along Y).");
+    def->enum_keys_map = &ConfigOptionEnum<BeltRotationAxis>::get_enum_values();
+    def->enum_values  = {"none", "x", "y", "z"};
+    def->enum_labels  = {L("None"), L("X"), L("Y"), L("Z")};
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionEnum<BeltRotationAxis>(BeltRotationAxis::X));
+
+    def = this->add("belt_slice_rotation_angle", coFloat);
+    def->label = L("Belt tilt angle");
+    def->category = L("Printable space");
+    def->tooltip = L("Tilt angle of the belt surface, in degrees. Most belt printers use "
+                     "45°. Positive values rotate counter-clockwise looking down the "
+                     "positive tilt axis; the magnitude is also the physical belt tilt "
+                     "used for bed rendering and support gravity.");
+    def->sidetext = L("°");
+    def->min = -180.;
+    def->max = 180.;
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionFloat(45.));
+
+    def = this->add("belt_slice_rotation_global", coBool);
+    def->label = L("Global");
+    def->category = L("Printable space");
+    def->tooltip = L("Treat the slicing rotation as part of the global forward transform "
+                     "that BeltBackTransform inverts before the machine-frame remap. "
+                     "Required for rotation-mode belt printers. "
+                     "Defaults to on because virtually all rotation-mode printers need it.");
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionBool(true));
+
+    def = this->add("belt_frame_tilt_decouple", coBool);
+    def->label = L("Decouple machine-frame tilt");
+    def->category = L("Printable space");
+    def->tooltip = L("Expert override: set the machine-frame (g-code shear/scale) tilt angle "
+                     "independently of the pre-slice rotation angle. When disabled, the "
+                     "machine-frame transform is derived from the belt tilt angle, so a single "
+                     "angle drives both stages. Enable only to compensate for a machine whose "
+                     "physical gantry tilt differs from the slicing rotation.");
+    def->mode = comExpert;
+    def->set_default_value(new ConfigOptionBool(false));
+
+    def = this->add("belt_frame_tilt_angle", coFloat);
+    def->label = L("Machine-frame tilt angle");
+    def->category = L("Printable space");
+    def->tooltip = L("Tilt angle (degrees) used to derive the machine-frame shear (tan) and "
+                     "scale (1/cos) applied to G-code. Only used when 'Decouple machine-frame "
+                     "tilt' is enabled; otherwise the belt tilt angle is used.");
+    def->sidetext = L("°");
+    def->min = -89.9;
+    def->max = 89.9;
+    def->mode = comExpert;
+    def->set_default_value(new ConfigOptionFloat(45.));
+
+    // G-code axis remap with sign
+    auto add_belt_remap = [this](const char *key, const char *label, const char *tooltip,
+                                  RemapAxis default_axis, ConfigOptionMode mode = comSimple) {
+        auto def = this->add(key, coEnum);
+        def->label = L(label);
+        def->category = L("Printable space");
+        def->tooltip = L(tooltip);
+        def->enum_keys_map = &ConfigOptionEnum<RemapAxis>::get_enum_values();
+        def->enum_values  = {"pos_x", "pos_y", "pos_z", "neg_x", "neg_y", "neg_z", "rev_x", "rev_y", "rev_z"};
+        def->enum_labels  = {L("+X"), L("+Y"), L("+Z"), L("-X"), L("-Y"), L("-Z"), L("Rev X"), L("Rev Y"), L("Rev Z")};
+        def->mode = mode;  // Visibility may also be gated by toggle_line in Tab.cpp
+        def->set_default_value(new ConfigOptionEnum<RemapAxis>(default_axis));
+    };
+
+    add_belt_remap("preslice_remap_x", "X",
+        "Before slicing, which model-space axis becomes the slicer's X axis. "
+        "Use this to re-orient the coordinate system so the slicer's XY plane matches "
+        "your belt printer's physical bed plane. For a printer whose bed is in the XZ plane, "
+        "set Y to +Z and Z to +Y (or -Y) to swap the vertical and belt-travel axes. "
+        "Default +X: no change.",
+        RemapAxis::PosX, comExpert);
+    add_belt_remap("preslice_remap_y", "Y",
+        "Before slicing, which model-space axis becomes the slicer's Y axis. "
+        "The slicer treats Y as one of the two horizontal bed axes. If your physical "
+        "belt surface runs along the Z axis, map Y to +Z here so the slicer slices "
+        "along the correct plane. Default +Y: no change.",
+        RemapAxis::PosY, comExpert);
+    add_belt_remap("preslice_remap_z", "Z",
+        "Before slicing, which model-space axis becomes the slicer's Z axis (layer stacking direction). "
+        "The slicer builds layers upward along this axis. If your printer's layer-stacking "
+        "direction is the physical Y axis, map Z to +Y (or -Y for inverted direction). "
+        "Rev mode mirrors relative to the build volume maximum. Default +Z: no change.",
+        RemapAxis::PosZ, comExpert);
+
+    def = this->add("preslice_remap_global", coBool);
+    def->label = L("Global");
+    def->category = L("Printable space");
+    def->tooltip = L("When enabled, the pre-slice axis remap accounts for each object's bed position. "
+                      "Without this, the remap is applied locally around each object's center, so "
+                      "objects at different positions don't get a position-dependent contribution. "
+                      "Mirrors the 'Global' option on the belt slicing rotation, but for the remap.");
+    def->mode = comExpert;
+    def->set_default_value(new ConfigOptionBool(false));
+
+    add_belt_remap("gcode_remap_x", "X", "Which slicing axis maps to machine X in G-code output. Applied AFTER slicing, during G-code generation.", RemapAxis::PosX, comExpert);
+    add_belt_remap("gcode_remap_y", "Y", "Which slicing axis maps to machine Y in G-code output. Applied AFTER slicing, during G-code generation.", RemapAxis::PosY, comExpert);
+    add_belt_remap("gcode_remap_z", "Z", "Which slicing axis maps to machine Z in G-code output. Applied AFTER slicing, during G-code generation.", RemapAxis::PosZ, comExpert);
+
+    // The machine-frame G-code transform (shear + scale) is no longer configured
+    // by per-axis keys: it is derived from the belt tilt (belt_slice_rotation axis
+    // + angle, or belt_frame_tilt_angle when decoupled) in MachineFrameTransform.
+
+    def = this->add("gcode_back_transform", coBool);
+    def->label = L("G-code back-transform");
+    def->category = L("Printable space");
+    def->tooltip = L("Undo the pre-slice mesh transform before applying the G-code axis remap "
+                      "and machine-frame shear/scale. Required for the standard belt-printer "
+                      "rotation pipeline.");
+    def->mode = comExpert;
+    def->set_default_value(new ConfigOptionBool(true));
+
+    def = this->add("belt_preslice_global", coBool);
+    def->label = L("Global mesh transforms");
+    def->category = L("Printable space");
+    def->tooltip = L("When enabled, pre-slice belt transforms (remap, shear, scale) account for "
+                      "each object's bed position, producing correct machine coordinates without "
+                      "relying on origin snap. Each instance gets its own PrintObject.");
+    def->mode = comExpert;
+    def->set_default_value(new ConfigOptionBool(true));
+
+    // First-layer plane: which surface defines "first layer" for fan / speed /
+    // accel decisions.  On belt printers the slicing-frame layer 0 is a tilted
+    // slab that no longer corresponds to the physical first printed layer.
+    // Auto picks BeltAffine when any belt-side affine transform is active
+    // (Z shear or slicing rotation), otherwise XY (legacy).
+    def = this->add("first_layer_plane", coEnum);
+    def->label = L("First layer plane");
+    def->category = L("Printable space");
+    def->tooltip = L("Selects the reference plane used to decide which extrusions get "
+                     "first-layer settings (no fan, slow speed, initial-layer accel/jerk, "
+                     "deferred temperature drop). On belt printers a single slicing layer "
+                     "contains paths at many machine-Z values, so layer-index based detection "
+                     "fails. Auto resolves to Belt affine plane when any belt-side affine "
+                     "transform (Z shear or slicing rotation) is active, otherwise XY (legacy). "
+                     "Pick XY explicitly to opt out and force the legacy slicing-layer-0 "
+                     "detection.");
+    def->enum_keys_map = &ConfigOptionEnum<FirstLayerPlaneMode>::get_enum_values();
+    def->enum_values   = {"auto", "xy", "yz", "xz", "belt_affine"};
+    def->enum_labels   = {L("Auto"), L("XY (machine bed)"), L("YZ"), L("XZ"), L("Belt affine plane")};
+    def->mode = comExpert;
+    // Auto, not BeltAffine: BeltAffine activates the plane evaluator unconditionally, so on a
+    // non-belt printer on_first_layer(point) stopped agreeing with the legacy slicing-layer-0
+    // test and first-layer speeds were skipped (brim printed at the volumetric fallback rather
+    // than initial_layer_speed). Auto resolves to BeltAffine only when belt_printer is set with
+    // a non-zero slicing rotation, and to XY (evaluator inactive, legacy behaviour) otherwise --
+    // which is what this option's own description promises.
+    def->set_default_value(new ConfigOptionEnum<FirstLayerPlaneMode>(FirstLayerPlaneMode::Auto));
+
+    def = this->add("first_layer_plane_offset", coFloat);
+    def->label = L("Belt plane offset");
+    def->category = L("Printable space");
+    def->tooltip = L("Shifts the first-layer plane along its normal (mm). For axis-aligned "
+                     "planes this is just a coordinate shift. Positive values move the plane "
+                     "away from the belt surface (deeper into the model).");
+    def->sidetext = L("mm");
+    def->min = -1000;
+    def->max =  1000;
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionFloat(0.0));
+
+    def = this->add("first_layer_plane_thickness", coFloat);
+    def->label = L("Plane band thickness");
+    def->category = L("Printable space");
+    def->tooltip = L("Thickness of one 'band' relative to the first-layer plane, in mm. "
+                     "Used as the unit by which 'No cooling for the first N layers' (and "
+                     "similar layer-count thresholds) is multiplied when the first-layer "
+                     "plane is active. -1 means use initial_layer_print_height.");
+    def->sidetext = L("mm");
+    def->min = -1;
+    def->max = 100;
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionFloat(-1.0));
+
+    // Belt support floor debug controls
+    def = this->add("belt_support_floor_offset", coFloat);
+    def->label = L("Support Floor Z offset");
+    def->category = L("Printable space");
+    def->tooltip = L("Shifts the computed belt floor up or down (mm). Negative values lower the floor, allowing more supports to survive. Use this to diagnose belt floor formula issues.");
+    def->sidetext = L("mm");
+    def->min = -500;
+    def->max = 500;
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionFloat(0));
+
+    {
+        auto def = this->add("belt_support_floor_mode", coEnum);
+        def->label = L("Floor mode");
+        def->category = L("Printable space");
+        def->tooltip = L("Controls belt floor awareness for supports. 'None' disables belt floor logic. "
+                         "'Generator only' stops support generation at the belt floor plane.");
+        def->enum_keys_map = &ConfigOptionEnum<BeltSupportFloorMode>::get_enum_values();
+        def->enum_values  = {"none", "generator_only"};
+        def->enum_labels  = {L("None"), L("Generator only")};
+        def->mode = comDevelop;
+        def->set_default_value(new ConfigOptionEnum<BeltSupportFloorMode>(BeltSupportFloorMode::GeneratorOnly));
+    }
+
+    {
+        auto def = this->add("belt_support_z_offset_mode", coEnum);
+        def->label = L("Z offset mode");
+        def->category = L("Printable space");
+        def->tooltip = L("How global Z offset is applied to support layers for belt printers with global shear. "
+                         "'None' = don't offset. 'Unconditional' = offset all layers. 'Raft only' = only offset raft layers.");
+        def->enum_keys_map = &ConfigOptionEnum<BeltSupportZOffsetMode>::get_enum_values();
+        def->enum_values  = {"none", "unconditional", "raft_only"};
+        def->enum_labels  = {L("None"), L("Unconditional"), L("Raft only")};
+        def->mode = comExpert;
+        def->set_default_value(new ConfigOptionEnum<BeltSupportZOffsetMode>(BeltSupportZOffsetMode::Unconditional));
+    }
+
+    def = this->add("enable_belt_purge_tower", coBool);
+    def->label = L("Enable belt purge tower");
+    def->category = L("Multimaterial");
+    def->tooltip = L("Belt-printer replacement for the wipe/prime tower. When enabled on a belt "
+                     "printer, a purge prism is automatically generated next to the printed parts "
+                     "and filament-change purging is routed into it (the classic wipe tower cannot "
+                     "be used on belt printers because its G-code bypasses the belt transform). "
+                     "Only available on belt printers.");
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionBool(false));
+
+    def = this->add("belt_purge_tower_width", coFloat);
+    def->label = L("Belt purge tower width");
+    def->category = L("Printable space");
+    def->tooltip = L("Width (machine X, across the belt) of the purge prism that is automatically "
+                     "generated on belt printers when the prime tower is enabled and multiple "
+                     "filaments are used. Filament-change purging is routed into this prism's "
+                     "extrusions instead of a classic wipe tower. Its height is computed "
+                     "automatically from the worst-case purge volume per layer: a wider prism "
+                     "results in a shorter one.");
+    def->sidetext = L("mm");
+    def->min = 1.;
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionFloat(35.));
+
     def = this->add("tree_support_branch_angle", coFloat);
     def->label = L("Tree support branch angle");
     def->category = L("Support");
@@ -7716,6 +8099,16 @@ void PrintConfigDef::init_fff_params()
         "It will not take effect unless the prime tower is enabled.");
     def->set_default_value(new ConfigOptionBool(false));
 
+    // Internal marker (not shown in any settings tab): identifies the auto-generated
+    // belt purge prism so it can be updated/removed by the auto-manager and aligned
+    // to the object layer grid by the backend. Persisted to 3mf like any per-object key.
+    def = this->add("belt_purge_tower_object", coBool);
+    def->category = L("Flush options");
+    def->label = L("Belt purge tower object");
+    def->tooltip = L("Marks the auto-generated belt purge prism. Managed automatically; do not set manually.");
+    def->mode = comDevelop;
+    def->set_default_value(new ConfigOptionBool(false));
+
     def = this->add("wipe_tower_bridging", coFloat);
     def->label = L("Maximal bridging distance");
     def->tooltip = L("Maximal distance between supports on sparse infill sections.");
@@ -12729,10 +13122,22 @@ Polygons get_bed_excluded_area(const PrintConfig& cfg)
 {
     const Pointfs exclude_area_points = cfg.bed_exclude_area.values;
 
+    // Belt printer: project exclusion zone points from the belt surface to machine-frame XY.
+    // On the belt surface Z=0, so the in-plane axis foreshortens by cos(tilt).  The tilt
+    // axis decides which bed axis foreshortens: tilt about X (belt along Y) scales Y,
+    // tilt about Y (belt along X) scales X.  Derived from belt_slice_rotation.
+    const bool is_belt = cfg.belt_printer.value;
+    const auto tilt    = BeltTransformPipeline::physical_tilt(
+        cfg.belt_slice_rotation.value, cfg.belt_slice_rotation_angle.value);
+    const double cos_x = is_belt ? std::cos(Geometry::deg2rad(tilt.tilt_x_deg)) : 1.0; // foreshortens Y
+    const double cos_y = is_belt ? std::cos(Geometry::deg2rad(tilt.tilt_y_deg)) : 1.0; // foreshortens X
+
     Polygon exclude_poly;
     for (int i = 0; i < exclude_area_points.size(); i++) {
         auto pt = exclude_area_points[i];
-        exclude_poly.points.emplace_back(scale_(pt.x()), scale_(pt.y()));
+        double x = is_belt ? pt.x() * cos_y : pt.x();
+        double y = is_belt ? pt.y() * cos_x : pt.y();
+        exclude_poly.points.emplace_back(scale_(x), scale_(y));
     }
 
     exclude_poly.make_counter_clockwise();

src/libslic3r/PrintConfig.hpp

@@ -252,6 +252,61 @@ enum class SlicingMode
     CloseHoles,
 };
 
+// Axis around which the mesh is rotated before slicing, when
+// `belt_slice_rotation` is set.  None disables the rotation stage.  This is the
+// single "belt tilt" axis: it drives both the pre-slice mesh rotation and the
+// post-slice machine-frame transform (shear + scale derived from the tilt angle).
+enum class BeltRotationAxis
+{
+    None = 0,
+    X    = 1,
+    Y    = 2,
+    Z    = 3,
+};
+
+enum class RemapAxis
+{
+    PosX = 0, PosY = 1, PosZ = 2,
+    NegX = 3, NegY = 4, NegZ = 5,
+    RevX = 6, RevY = 7, RevZ = 8,  // Reversed: max - pos
+};
+
+enum class BeltSupportFloorMode
+{
+    None,           // No belt floor awareness
+    GeneratorOnly,  // Only in tree support drop_nodes/contact_points
+    ClipOnly,       // Only post-processing clipping
+    Both,           // Both generator and clipping
+};
+
+enum class BeltSupportZOffsetMode
+{
+    None,           // Don't apply global_z_offset to support layers
+    Unconditional,  // Apply to all support layers
+    RaftOnly,       // Only apply to raft layers
+};
+
+// Selects which plane the slicer treats as the "first layer plane" — the
+// reference surface used to decide which extrusions get first-layer settings
+// (no fan, slow speed, initial-layer accel/jerk, deferred temperature drop).
+//
+// Auto resolves to:
+//   - XY (inactive, legacy behavior) for non-belt printers and for belt
+//     printers with no active belt-side transform.
+//   - BeltAffine for belt printers with any active belt-side affine
+//     transform (Z shear, slicing rotation, or both).
+//
+// XY is also used as an explicit "opt out" mode that forces legacy
+// per-layer first-layer detection even on belt printers.
+enum class FirstLayerPlaneMode
+{
+    Auto = 0,
+    XY,
+    YZ,
+    XZ,
+    BeltAffine,   // formerly BeltShear; renamed to reflect rotation support
+};
+
 enum SupportMaterialPattern {
     smpDefault,
     smpRectilinear, smpRectilinearGrid, smpHoneycomb,
@@ -359,6 +414,10 @@ enum BrimType {
     btInnerOnly,
     btOuterAndInner,
     btNoBrim,
+    // Belt printers: brim only where the part first touches the belt, nothing after
+    // that.  Appended last so no existing value shifts.  On a non-belt printer this
+    // has no meaning and behaves as btOuterOnly.
+    btLeadingEdgeOnly,
 };
 
 enum TimelapseType : int {
@@ -670,6 +729,11 @@ CONFIG_OPTION_ENUM_DECLARE_STATIC_MAPS(NoiseType)
 CONFIG_OPTION_ENUM_DECLARE_STATIC_MAPS(InfillPattern)
 CONFIG_OPTION_ENUM_DECLARE_STATIC_MAPS(IroningType)
 CONFIG_OPTION_ENUM_DECLARE_STATIC_MAPS(SlicingMode)
+CONFIG_OPTION_ENUM_DECLARE_STATIC_MAPS(BeltRotationAxis)
+CONFIG_OPTION_ENUM_DECLARE_STATIC_MAPS(RemapAxis)
+CONFIG_OPTION_ENUM_DECLARE_STATIC_MAPS(BeltSupportFloorMode)
+CONFIG_OPTION_ENUM_DECLARE_STATIC_MAPS(BeltSupportZOffsetMode)
+CONFIG_OPTION_ENUM_DECLARE_STATIC_MAPS(FirstLayerPlaneMode)
 CONFIG_OPTION_ENUM_DECLARE_STATIC_MAPS(SupportMaterialPattern)
 CONFIG_OPTION_ENUM_DECLARE_STATIC_MAPS(SupportMaterialStyle)
 CONFIG_OPTION_ENUM_DECLARE_STATIC_MAPS(SupportMaterialInterfacePattern)
@@ -1111,6 +1175,8 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionBool,                brim_use_efc_outline))
     ((ConfigOptionEnum<BrimType>,      brim_type))
     ((ConfigOptionFloat,               brim_width))
+    ((ConfigOptionFloat,               leading_brim_length))
+    ((ConfigOptionFloat,               extra_brim_width))
     ((ConfigOptionFloat,               brim_ears_detection_length))
     ((ConfigOptionFloat,               brim_ears_max_angle))
     ((ConfigOptionBool,                brim_ears_outer_only))
@@ -1194,6 +1260,9 @@ PRINT_CONFIG_CLASS_DEFINE(
     // BBS
     ((ConfigOptionBool,                flush_into_infill))
     ((ConfigOptionBool,                flush_into_support))
+    // Marker for the auto-generated belt purge prism; identifies the object to
+    // the auto-manager (GUI) and the layer-grid alignment step (backend).
+    ((ConfigOptionBool,                belt_purge_tower_object))
     // BBS
     ((ConfigOptionFloat,              tree_support_branch_distance))
     ((ConfigOptionFloat,              tree_support_tip_diameter))
@@ -1744,6 +1813,45 @@ PRINT_CONFIG_CLASS_DERIVED_DEFINE(
     PrintConfig,
     (MachineEnvelopeConfig, GCodeConfig),
 
+    // Build plate tilt for off-axis gravity support generation (printer-level setting).
+    ((ConfigOptionFloat,               build_plate_tilt_x))
+    ((ConfigOptionFloat,               build_plate_tilt_y))
+    // Belt printer settings (printer-level).
+    ((ConfigOptionBool,                belt_printer))
+    ((ConfigOptionBool,                belt_printer_infinite_y))
+    // Mesh rotation applied before slicing — the single source of truth for the
+    // physical belt tilt.  Its angle + axis drive bed rendering, support gravity
+    // tilt, the bed-exclusion projection, AND the post-slice machine-frame
+    // transform (shear + scale, derived from the tilt angle; see
+    // MachineFrameTransform).  Isometric (no distortion) on the mesh side; the
+    // g-code back-transform inverts the rotation before the machine-frame stage.
+    ((ConfigOptionEnum<BeltRotationAxis>, belt_slice_rotation))
+    ((ConfigOptionFloat,                  belt_slice_rotation_angle))
+    ((ConfigOptionBool,                   belt_slice_rotation_global))
+    // Expert override: decouple the machine-frame tilt angle from the pre-slice
+    // rotation angle.  When disabled, the machine frame uses belt_slice_rotation_angle.
+    ((ConfigOptionBool,                   belt_frame_tilt_decouple))
+    ((ConfigOptionFloat,                  belt_frame_tilt_angle))
+    ((ConfigOptionEnum<RemapAxis>,  preslice_remap_x))
+    ((ConfigOptionEnum<RemapAxis>,  preslice_remap_y))
+    ((ConfigOptionEnum<RemapAxis>,  preslice_remap_z))
+    ((ConfigOptionBool,             preslice_remap_global))
+    ((ConfigOptionEnum<RemapAxis>,  gcode_remap_x))
+    ((ConfigOptionEnum<RemapAxis>,  gcode_remap_y))
+    ((ConfigOptionEnum<RemapAxis>,  gcode_remap_z))
+    ((ConfigOptionBool,                 gcode_back_transform))
+    ((ConfigOptionBool,                 belt_preslice_global))
+    ((ConfigOptionEnum<FirstLayerPlaneMode>, first_layer_plane))
+    ((ConfigOptionFloat,                first_layer_plane_offset))
+    ((ConfigOptionFloat,                first_layer_plane_thickness))
+    ((ConfigOptionFloat,                          belt_support_floor_offset))
+    ((ConfigOptionEnum<BeltSupportFloorMode>,     belt_support_floor_mode))
+    ((ConfigOptionEnum<BeltSupportZOffsetMode>,   belt_support_z_offset_mode))
+    // Width (machine X, across the belt) of the auto-generated belt purge prism.
+    ((ConfigOptionFloat,                          belt_purge_tower_width))
+    // Belt-printer-only "type" of purge tower: enables the auto-generated belt
+    // purge prism (the belt replacement for the classic wipe/prime tower).
+    ((ConfigOptionBool,                           enable_belt_purge_tower))
     //BBS
     ((ConfigOptionInts,               additional_cooling_fan_speed))
     ((ConfigOptionInts,               close_additional_fan_first_x_layers))

src/libslic3r/PrintObject.cpp

@@ -2,6 +2,9 @@
 #include "Model.hpp"
 #include "Point.hpp"
 #include "Print.hpp"
+#include "BeltTransform.hpp"
+
+#include <thread>
 #include "BoundingBox.hpp"
 #include "ClipperUtils.hpp"
 #include "Clipper2Utils.hpp"
@@ -13,6 +16,7 @@
 #include "PrintConfig.hpp"
 #include "SLA/IndexedMesh.hpp"
 #include "Support/SupportMaterial.hpp"
+#include "Support/SupportCommon.hpp"
 #include "Support/SupportSpotsGenerator.hpp"
 #include "Support/TreeSupport.hpp"
 #include "Surface.hpp"
@@ -456,11 +460,15 @@ std::vector<std::set<int>> PrintObject::detect_extruder_geometric_unprintables()
 // 3) Generates perimeters, gap fills and fill regions (fill regions of type stInternal).
 void PrintObject::make_perimeters()
 {
+    BOOST_LOG_TRIVIAL(trace) << "[BELTRACE] make_perimeters request tid=" << std::this_thread::get_id() << " obj=" << this;
     // prerequisites
     this->slice();
 
-    if (! this->set_started(posPerimeters))
+    if (! this->set_started(posPerimeters)) {
+        BOOST_LOG_TRIVIAL(trace) << "[BELTRACE] make_perimeters SKIP tid=" << std::this_thread::get_id() << " obj=" << this << " (already started/done)";
         return;
+    }
+    BOOST_LOG_TRIVIAL(trace) << "[BELTRACE] make_perimeters ENTER tid=" << std::this_thread::get_id() << " obj=" << this;
 
     m_print->set_status(15, L("Generating walls"));
     BOOST_LOG_TRIVIAL(info) << "Generating walls..." << log_memory_info();
@@ -558,6 +566,7 @@ void PrintObject::make_perimeters()
     m_print->throw_if_canceled();
     BOOST_LOG_TRIVIAL(debug) << "Generating perimeters in parallel - end";
 
+    BOOST_LOG_TRIVIAL(trace) << "[BELTRACE] make_perimeters EXIT tid=" << std::this_thread::get_id() << " obj=" << this;
     this->set_done(posPerimeters);
 }
 
@@ -946,7 +955,9 @@ void PrintObject::detect_overhangs_for_lift()
 
 void PrintObject::generate_support_material()
 {
+    BOOST_LOG_TRIVIAL(trace) << "[BELTRACE] generate_support_material request tid=" << std::this_thread::get_id() << " obj=" << this;
     if (this->set_started(posSupportMaterial)) {
+        BOOST_LOG_TRIVIAL(trace) << "[BELTRACE] generate_support_material ENTER tid=" << std::this_thread::get_id() << " obj=" << this;
         this->clear_support_layers();
 
         if(!has_support() && !m_print->get_no_check_flag()) {
@@ -987,7 +998,17 @@ void PrintObject::generate_support_material()
             this->_generate_support_material();
             m_print->throw_if_canceled();
         }
+        // Belt brim rides here rather than in the brim step because its apron
+        // prologue introduces print_z values below the object's first layer, and
+        // those must exist before ToolOrdering is built at psWipeTower - one step
+        // ahead of psSkirtBrim.  The brim options already invalidate
+        // posSupportMaterial, so this needs no extra invalidation edges.
+        make_belt_brim(*this);
+        m_print->throw_if_canceled();
+        BOOST_LOG_TRIVIAL(trace) << "[BELTRACE] generate_support_material EXIT tid=" << std::this_thread::get_id() << " obj=" << this;
         this->set_done(posSupportMaterial);
+    } else {
+        BOOST_LOG_TRIVIAL(trace) << "[BELTRACE] generate_support_material SKIP tid=" << std::this_thread::get_id() << " obj=" << this << " (already started/done)";
     }
 }
 
@@ -1124,6 +1145,9 @@ void PrintObject::clear_layers()
         for (Layer *l : m_layers)
             delete l;
         m_layers.clear();
+        for (Layer *l : m_belt_truncated_layers)
+            delete l;
+        m_belt_truncated_layers.clear();
     }
 }
 
@@ -1157,6 +1181,95 @@ void PrintObject::clear_support_layers()
             l->cantilevers.clear();
         }
     }
+    // Belt brim is owned by the same step, so it must die with it or an
+    // invalidate-without-rerun would leave stale bands (and stale prologue Zs)
+    // behind.  Unconditional: unlike support layers it is never shared.
+    this->clear_belt_brim();
+}
+
+// Belt brim ------------------------------------------------------------------
+//
+// The tilt test is answered from the print CONFIG, not from SlicingParameters:
+// invalidating posSupportMaterial clears m_slicing_params.valid, and this is
+// queried from Print::process() dispatch, Brim.cpp and the G-code emitter, where
+// a stale zero shear factor would silently drop the brim.  BeltBrim.cpp itself
+// reads the real belt floor through BeltFloorContext, where the parameters are
+// guaranteed current.
+bool PrintObject::has_belt_brim() const
+{
+    if (! m_print->has_tilted_belt())
+        return false;
+    if (! this->belt_brim_instances_compatible())
+        return false;
+    if (m_config.brim_type == btNoBrim)
+        return false;
+    // An inner-only brim has no leading/extra geometry: leading_brim_length and
+    // extra_brim_width both widen the OUTER ring, which btInnerOnly never emits, so it
+    // produces nothing unless brim_width itself is positive.  Every other brim type is
+    // satisfied by any one of the three widths.  Requiring the width here (instead of
+    // "any width") stops has_belt_brim() - and therefore Print::validate() - from
+    // rejecting the prime tower / spiral vase for a brim that would never be drawn.
+    if (m_config.brim_type == btInnerOnly) {
+        if (m_config.brim_width.value <= 0.)
+            return false;
+    } else if (m_config.brim_width.value <= 0. && m_config.leading_brim_length.value <= 0.
+               && m_config.extra_brim_width.value <= 0.) {
+        return false;
+    }
+    return ! this->has_raft();
+}
+
+unsigned int PrintObject::belt_brim_filament() const
+{
+    // 1-based, matching PrintRegion::outer_wall_filament_id and the raw values pushed
+    // into LayerTools::extruders in ToolOrdering::collect_extruders (the whole list is
+    // reindexed to 0-based later).  Lowest positive outer-wall filament over the
+    // printing regions; 1 when none is explicitly set.
+    unsigned int brim_filament = 0;
+    for (size_t i = 0; i < this->num_printing_regions(); ++ i) {
+        const unsigned int f = this->printing_region(i).config().outer_wall_filament_id.value;
+        if (f > 0 && (brim_filament == 0 || f < brim_filament))
+            brim_filament = f;
+    }
+    return brim_filament == 0 ? 1u : brim_filament;
+}
+
+bool PrintObject::belt_brim_instances_compatible() const
+{
+    // One set of bands is shared by every instance of this object, so they must all sit at
+    // the same height on the belt.  Moving an instance ALONG the belt axis changes its
+    // physical belt-floor Z and would put its brim at the wrong height; moving it ACROSS
+    // the belt does not, so side-by-side copies are fine.
+    //
+    // belt_force_separate() in PrintApply.cpp already gives one instance per PrintObject
+    // whenever a global belt flag is set, which the shipped belt profiles do - this only
+    // matters for configurations that do not.
+    if (m_instances.size() <= 1)
+        return true;
+    const int    axis = m_slicing_params.belt_floor_from_axis;
+    const Point &ref  = m_instances.front().shift;
+    for (const PrintInstance &inst : m_instances) {
+        const coord_t along = axis == 0 ? inst.shift.x() - ref.x() : inst.shift.y() - ref.y();
+        if (std::abs(along) > SCALED_EPSILON)
+            return false;
+    }
+    return true;
+}
+
+void PrintObject::clear_belt_brim()
+{
+    m_belt_brim_by_layer.clear();
+    m_belt_brim_areas_by_layer.clear();
+    m_belt_brim_prologue.clear();
+}
+
+void PrintObject::set_belt_brim(std::vector<ExtrusionEntityCollection> &&by_layer,
+                                std::vector<ExPolygons>                &&areas,
+                                std::vector<BeltBrimBand>              &&prologue)
+{
+    m_belt_brim_by_layer       = std::move(by_layer);
+    m_belt_brim_areas_by_layer = std::move(areas);
+    m_belt_brim_prologue       = std::move(prologue);
 }
 
 std::shared_ptr<TreeSupportData> PrintObject::alloc_tree_support_preview_cache()
@@ -1199,6 +1312,8 @@ bool PrintObject::invalidate_state_by_config_options(
     bool invalidated = false;
     for (const t_config_option_key &opt_key : opt_keys) {
         if (   opt_key == "brim_width"
+            || opt_key == "leading_brim_length"
+            || opt_key == "extra_brim_width"
             || opt_key == "brim_object_gap"
             || opt_key == "brim_use_efc_outline"
             || opt_key == "brim_type"
@@ -1580,7 +1695,8 @@ bool PrintObject::invalidate_state_by_config_options(
         } else if (
                opt_key == "flush_into_infill"
             || opt_key == "flush_into_objects"
-            || opt_key == "flush_into_support") {
+            || opt_key == "flush_into_support"
+            || opt_key == "belt_purge_tower_object") {
             invalidated |= m_print->invalidate_step(psWipeTower);
             invalidated |= m_print->invalidate_step(psGCodeExport);
         } else {
@@ -1613,9 +1729,15 @@ bool PrintObject::invalidate_step(PrintObjectStep step)
 		invalidated |= this->invalidate_steps({ posPerimeters, posPrepareInfill, posInfill, posIroning, posContouring, posSupportMaterial, posSimplifyPath, posSimplifyInfill });
         invalidated |= m_print->invalidate_steps({ psSkirtBrim });
         m_slicing_params.valid = false;
+        // The exact belt_floor_z_shift is recomputed when slice() runs again.
+        m_belt_floor_z_shift_cache_valid = false;
     } else if (step == posSupportMaterial) {
         invalidated |= this->invalidate_steps({ posSimplifySupportPath });
         invalidated |= m_print->invalidate_steps({ psSkirtBrim });
+        // SlicingParameters depend on support config (enable_support /
+        // raft_layers / enforce_support_layers feed min/max layer height in
+        // Slicing.cpp), so invalidate them here.  The vertex-scan
+        // belt_floor_z_shift is preserved via m_belt_floor_z_shift_cached.
         m_slicing_params.valid = false;
     }
 
@@ -1636,6 +1758,7 @@ bool PrintObject::invalidate_all_steps()
     bool result = inherited_invalidated || print_invalidated;
 	// Then reset some of the depending values.
 	m_slicing_params.valid = false;
+	m_belt_floor_z_shift_cache_valid = false;
 	return result;
 }
 
@@ -3973,8 +4096,28 @@ void PrintObject::update_slicing_parameters()
 {
     // Orca: updated function call for XYZ shrinkage compensation
     if (!m_slicing_params.valid) {
-          m_slicing_params = SlicingParameters::create_from_config(this->print()->config(), m_config, this->model_object()->max_z(),
+          coordf_t object_height = this->model_object()->max_z();
+          BeltTransformPipeline::BeltFloorParams belt_floor;
+          const auto &pcfg = this->print()->config();
+          if (pcfg.belt_printer.value) {
+              BoundingBoxf3 bb = BeltTransformPipeline::remap_bbox(*this->model_object(), pcfg);
+              if (BeltTransformPipeline::has_preslice_remap(pcfg))
+                  object_height = bb.size().z();
+              auto hr = BeltTransformPipeline::compute_belt_height_and_floor(pcfg, bb, object_height);
+              object_height = hr.object_height;
+              belt_floor    = hr.floor_params;
+          }
+          m_slicing_params = SlicingParameters::create_from_config(pcfg, m_config, object_height,
                                                                    this->object_extruders(), this->print()->shrinkage_compensation());
+          // Populate belt floor parameters into slicing params for support clipping.
+          m_slicing_params.belt_floor_shear_factor = belt_floor.shear_factor;
+          m_slicing_params.belt_floor_from_axis    = belt_floor.from_axis;
+          m_slicing_params.belt_floor_z_shift     = belt_floor.z_shift;
+          // Prefer the vertex-scan z_shift over the bbox approximation when
+          // slice() has already produced one (e.g. this rebuild was triggered
+          // by a support-config change, which doesn't move the belt floor).
+          if (m_belt_floor_z_shift_cache_valid)
+              m_slicing_params.belt_floor_z_shift = m_belt_floor_z_shift_cached;
       }
 }
 
@@ -4015,9 +4158,24 @@ SlicingParameters PrintObject::slicing_parameters(const DynamicPrintConfig &full
     sort_remove_duplicates(object_extruders);
     //FIXME add painting extruders
 
-    if (object_max_z <= 0.f)
+    BeltTransformPipeline::BeltFloorParams belt_floor;
-        object_max_z = (float)model_object.raw_bounding_box().size().z();
+    if (object_max_z <= 0.f) {
-    return SlicingParameters::create_from_config(print_config, object_config, object_max_z, object_extruders, object_shrinkage_compensation);
+        BoundingBoxf3 bb = model_object.raw_bounding_box();
+        object_max_z = (float)bb.size().z();
+        if (print_config.belt_printer.value) {
+            bb = BeltTransformPipeline::remap_bbox(model_object, print_config);
+            if (BeltTransformPipeline::has_preslice_remap(print_config))
+                object_max_z = (float)bb.size().z();
+            auto hr = BeltTransformPipeline::compute_belt_height_and_floor(print_config, bb, object_max_z);
+            object_max_z = (float)hr.object_height;
+            belt_floor   = hr.floor_params;
+        }
+    }
+    SlicingParameters params = SlicingParameters::create_from_config(print_config, object_config, object_max_z, object_extruders, object_shrinkage_compensation);
+    params.belt_floor_shear_factor = belt_floor.shear_factor;
+    params.belt_floor_from_axis    = belt_floor.from_axis;
+    params.belt_floor_z_shift     = belt_floor.z_shift;
+    return params;
 }
 
 // returns 0-based indices of extruders used to print the object (without brim, support and other helper extrusions)
@@ -4526,6 +4684,67 @@ void PrintObject::combine_infill()
     }
 }
 
+// Belt printer: clip an ExtrusionEntityCollection to a region defined by clip_expoly.
+// Handles ExtrusionPath, ExtrusionMultiPath, ExtrusionLoop, and nested ExtrusionEntityCollection.
+static void clip_support_fills(ExtrusionEntityCollection &fills, const ExPolygons &clip_region)
+{
+    ExtrusionEntitiesPtr new_entities;
+    for (ExtrusionEntity *entity : fills.entities) {
+        if (auto *path = dynamic_cast<ExtrusionPath *>(entity)) {
+            ExtrusionEntityCollection clipped;
+            path->intersect_expolygons(clip_region, &clipped);
+            if (!clipped.empty()) {
+                for (ExtrusionEntity *e : clipped.entities)
+                    new_entities.push_back(e->clone());
+            }
+            delete entity;
+        } else if (auto *multipath = dynamic_cast<ExtrusionMultiPath *>(entity)) {
+            ExtrusionPaths new_paths;
+            for (const ExtrusionPath &p : multipath->paths) {
+                ExtrusionEntityCollection clipped;
+                p.intersect_expolygons(clip_region, &clipped);
+                for (ExtrusionEntity *e : clipped.entities)
+                    if (auto *cp = dynamic_cast<ExtrusionPath *>(e))
+                        new_paths.push_back(std::move(*cp));
+            }
+            if (!new_paths.empty()) {
+                multipath->paths = std::move(new_paths);
+                new_entities.push_back(multipath);
+            } else {
+                delete entity;
+            }
+        } else if (auto *loop = dynamic_cast<ExtrusionLoop *>(entity)) {
+            ExtrusionPaths new_paths;
+            for (const ExtrusionPath &p : loop->paths) {
+                ExtrusionEntityCollection clipped;
+                p.intersect_expolygons(clip_region, &clipped);
+                for (ExtrusionEntity *e : clipped.entities)
+                    if (auto *cp = dynamic_cast<ExtrusionPath *>(e))
+                        new_paths.push_back(std::move(*cp));
+            }
+            if (!new_paths.empty()) {
+                // Loop is no longer a closed loop after clipping; emit as individual paths.
+                for (auto &p : new_paths)
+                    new_entities.push_back(new ExtrusionPath(std::move(p)));
+                delete entity;
+            } else {
+                delete entity;
+            }
+        } else if (auto *coll = dynamic_cast<ExtrusionEntityCollection *>(entity)) {
+            clip_support_fills(*coll, clip_region);
+            if (!coll->empty()) {
+                new_entities.push_back(coll);
+            } else {
+                delete entity;
+            }
+        } else {
+            // Unknown entity type — keep as-is.
+            new_entities.push_back(entity);
+        }
+    }
+    fills.entities = std::move(new_entities);
+}
+
 void PrintObject::_generate_support_material()
 {
     if (is_tree(m_config.support_type.value)) {
@@ -4537,6 +4756,25 @@ void PrintObject::_generate_support_material()
         PrintObjectSupportMaterial support_material(this, m_slicing_params);
         support_material.generate(*this);
     }
+    // Global Z offset for support layers:
+    // - Normal support: layers already inherit global_z_offset from object layers.
+    // - Non-organic tree support (slim/strong/hybrid): plan_layer_heights() reads
+    //   from globally-offset object layers, so support layers already have it.
+    // - Organic tree support: generate_tree_support_3D() computes its own Z values
+    //   independently and does NOT inherit the offset — apply it here.
+    // Belt floor polygon clipping for non-organic tree support is done inside
+    // draw_circles() before area_groups and toolpaths are built.
+    if (is_tree(m_config.support_type.value) && std::abs(m_belt_global_z_offset) > EPSILON) {
+        // Resolve effective support style (same logic as SupportParameters).
+        auto style = m_config.support_style.value;
+        if (style == smsDefault)
+            style = smsTreeOrganic;
+        if (style == smsTreeOrganic) {
+            for (SupportLayer *sl : m_support_layers)
+                sl->print_z += m_belt_global_z_offset;
+        }
+    }
+
 }
 
 // BBS

src/libslic3r/PrintObjectSlice.cpp

@@ -1,4 +1,6 @@
 #include <boost/log/trivial.hpp>
+#include <limits>
+#include <thread>
 
 #include <tbb/parallel_for.h>
 
@@ -9,6 +11,9 @@
 #include "Layer.hpp"
 #include "MultiMaterialSegmentation.hpp"
 #include "Print.hpp"
+#include "BeltTransform.hpp"
+#include "BeltSliceStrategy.hpp"
+#include "Geometry.hpp"
 //BBS
 #include "ShortestPath.hpp"
 #include "libslic3r/Feature/Interlocking/InterlockingGenerator.hpp"
@@ -152,7 +157,8 @@ static std::vector<VolumeSlices> slice_volumes_inner(
     ModelVolumePtrs                                           model_volumes,
     const std::vector<PrintObjectRegions::LayerRangeRegions> &layer_ranges,
     const std::vector<float>                                 &zs,
-    const std::function<void()>                              &throw_on_cancel_callback)
+    const std::function<void()>                              &throw_on_cancel_callback,
+    double                                                   *out_belt_min_z = nullptr)
 {
     model_volumes_sort_by_id(model_volumes);
 
@@ -167,6 +173,10 @@ static std::vector<VolumeSlices> slice_volumes_inner(
     params_base.closing_radius = print_object_config.slice_closing_radius.value;
     params_base.extra_offset   = 0;
     params_base.trafo          = object_trafo;
+    // Pre-slice mesh transforms: axis remap (standalone — works without belt
+    // mode), belt rotation, and the per-object Z-shift.  Owned by BeltSliceStrategy
+    // so this belt/remap-specific logic stays out of the generic slicing pipeline.
+    BeltSliceStrategy::apply_preslice_transforms(params_base.trafo, print_config, model_volumes, out_belt_min_z);
     //BBS: 0.0025mm is safe enough to simplify the data to speed slicing up for high-resolution model.
     //Also has on influence on arc fitting which has default resolution 0.0125mm.
     params_base.resolution = print_config.resolution <= 0.001 ? 0.0f : 0.0025;
@@ -300,14 +310,39 @@ static std::vector<std::vector<ExPolygons>> slices_to_regions(
                 }
             } else {
                 zs_complex.reserve(zs.size());
+                // region.bbox is computed in pre-belt-transform slicer space (see PrintApply.cpp::trafo_for_bbox).
+                // When belt transforms are active, layer Z values are in post-rotation/shear/scale/remap space,
+                // so the Z components of region.bbox aren't comparable to z. Skipping the Z filter here
+                // pushes those layers into the parallel_for path below, which handles multi-volume
+                // clipping per layer without relying on the bbox Z range.
+                const bool bbox_z_in_layer_frame = !(print_config.belt_printer.value &&
+                    (BeltTransformPipeline::has_rotation(print_config)
+                        || BeltTransformPipeline::has_preslice_remap(print_config)));
+                // Belt-transform addendum: with bbox-Z untrusted, the simple path's
+                // "first model_part wins" logic drops subsequent volumes' slices unless
+                // they XY-overlap with the first.  Assemblies whose volumes are stacked
+                // or side-by-side in pre-transform Z (different bbox.z ranges) thus lose
+                // the volumes that originally sat outside the first volume's Z range —
+                // showing up as truncation at the top or bottom of the assembly.  Force
+                // every layer in a multi-volume range through the parallel_for path,
+                // which correctly merges all volumes per layer.
+                int num_model_parts = 0;
+                for (const PrintObjectRegions::VolumeRegion &vr : layer_range.volume_regions)
+                    if (vr.model_volume->is_model_part())
+                        ++num_model_parts;
+                const bool force_complex_for_belt = !bbox_z_in_layer_frame && num_model_parts > 1;
                 for (; z_idx < zs.size() && zs[z_idx] < layer_range.layer_height_range.second; ++ z_idx) {
                     float z                          = zs[z_idx];
+                    if (force_complex_for_belt) {
+                        zs_complex.push_back({ z_idx, z });
+                        continue;
+                    }
                     int   idx_first_printable_region = -1;
                     bool  complex                    = false;
                     std::vector<int> printable_region_ids;
                     for (int idx_region = 0; idx_region < int(layer_range.volume_regions.size()); ++ idx_region) {
                         const PrintObjectRegions::VolumeRegion &region = layer_range.volume_regions[idx_region];
-                        if (region.bbox->min().z() <= z && region.bbox->max().z() >= z) {
+                        if (!bbox_z_in_layer_frame || (region.bbox->min().z() <= z && region.bbox->max().z() >= z)) {
                             if (region.model_volume->is_model_part())
                                 printable_region_ids.push_back(idx_region);
 
@@ -318,7 +353,9 @@ static std::vector<std::vector<ExPolygons>> slices_to_regions(
                                 // Test for overlap with some other region.
                                 for (int idx_region2 = idx_first_printable_region; idx_region2 < idx_region; ++ idx_region2) {
                                     const PrintObjectRegions::VolumeRegion &region2 = layer_range.volume_regions[idx_region2];
-                                    if (region2.bbox->min().z() <= z && region2.bbox->max().z() >= z && overlap_in_xy(*region.bbox, *region2.bbox)) {
+                                    const bool region2_in_z = !bbox_z_in_layer_frame
+                                        || (region2.bbox->min().z() <= z && region2.bbox->max().z() >= z);
+                                    if (region2_in_z && overlap_in_xy(*region.bbox, *region2.bbox)) {
                                         complex = true;
                                         break;
                                     }
@@ -823,8 +860,12 @@ void groupingVolumesForBrim(PrintObject* object, LayerPtrs& layers, int firstLay
 // Resulting expolygons of layer regions are marked as Internal.
 void PrintObject::slice()
 {
-    if (! this->set_started(posSlice))
+    BOOST_LOG_TRIVIAL(trace) << "[BELTRACE] slice request tid=" << std::this_thread::get_id() << " obj=" << this;
+    if (! this->set_started(posSlice)) {
+        BOOST_LOG_TRIVIAL(trace) << "[BELTRACE] slice SKIP tid=" << std::this_thread::get_id() << " obj=" << this << " (already started/done)";
         return;
+    }
+    BOOST_LOG_TRIVIAL(trace) << "[BELTRACE] slice ENTER tid=" << std::this_thread::get_id() << " obj=" << this;
     //BBS: add flag to reload scene for shell rendering
     m_print->set_status(5, L("Slicing mesh"), PrintBase::SlicingStatus::RELOAD_SCENE);
     std::vector<coordf_t> layer_height_profile;
@@ -835,6 +876,34 @@ void PrintObject::slice()
     m_layers = new_layers(this, generate_object_layers(m_slicing_params, layer_height_profile, m_config.precise_z_height.value));
     this->slice_volumes();
     m_print->throw_if_canceled();
+
+    // Belt floor Z-shift: where is the belt surface in final slicer space?
+    //
+    // The belt surface is at model_Y=0 (XZ belt plane). After the full
+    // pipeline (trafo_centered → pre_remap → shear → z_shift), the belt
+    // surface equation in slicer space is:
+    //   Z_belt = sf * from_axis + belt_surface_z_centered + z_shift_val
+    //
+    // belt_surface_z_centered = remapped_bbox.min.z() (the Z position of
+    //   the belt surface in centered-pre-shear slicer space, which is 0
+    //   without pre-remap but nonzero when e.g. Y↔Z swap shifts the belt
+    //   surface away from Z=0 by the centering offset).
+    //
+    // z_shift_val = max(0, -m_belt_min_z) (lifts mesh above Z=0).
+    //
+    // So: belt_floor_z_shift = remapped_bb.min.z() + z_shift_val
+    if (std::abs(m_slicing_params.belt_floor_shear_factor) > EPSILON) {
+        double z_shift_val = (m_belt_min_z < 0.) ? -m_belt_min_z : 0.;
+        // With pre-remap, the belt surface (model_Y=0) may not be at Z=0 in
+        // centered slicer space — add the remapped bbox min Z to compensate.
+        // Without pre-remap, the belt surface IS at Z=0 and bb.min.z() is
+        // already folded into m_belt_min_z, so use 0.
+        const auto &pcfg = this->print()->config();
+        double belt_surface_z = BeltTransformPipeline::has_preslice_remap(pcfg)
+            ? BeltTransformPipeline::remap_bbox(*this->model_object(), pcfg).min.z() : 0.;
+        m_slicing_params.belt_floor_z_shift = belt_surface_z + z_shift_val;
+    }
+
     int firstLayerReplacedBy = 0;
 
 #if 0
@@ -873,7 +942,193 @@ void PrintObject::slice()
     if (m_layers.empty())
         throw Slic3r::SlicingError(L("No layers were detected. You might want to repair your STL file(s) or check their size or thickness and retry.\n"));
 
+    // Belt printer global mode: offset all layer Z values so objects at
+    // different bed positions print at different heights on the tilted belt.
+    // This is a post-slicing adjustment — the sliced geometry is identical
+    // regardless of global mode, only the output Z coordinates change.
+    {
+        const auto &pcfg = this->print()->config();
+        BOOST_LOG_TRIVIAL(trace) << "Belt global check: belt_printer=" << pcfg.belt_printer.value
+            << " belt_slice_rotation=" << int(pcfg.belt_slice_rotation.value)
+            << " belt_slice_rotation_global=" << pcfg.belt_slice_rotation_global.value
+            << " belt_preslice_global=" << pcfg.belt_preslice_global.value
+            << " object=" << this->model_object()->name;
+        if (pcfg.belt_printer.value) {
+
+            Point inst_shift = this->instances().empty() ? Point(0, 0)
+                : this->instances().front().shift - this->center_offset();
+            BOOST_LOG_TRIVIAL(trace) << "Belt global: object " << this->model_object()->name
+                << " instances=" << this->instances().size()
+                << " shift=(" << unscale<double>(inst_shift.x()) << ", " << unscale<double>(inst_shift.y()) << ")";
+
+            // Per-object Z-shift compensation, applied regardless of global mode.
+            //
+            // BeltSliceStrategy::apply_preslice_transforms lifts the mesh by max(0, -m_belt_min_z)
+            // so the slicer can slice with slicer_z >= 0.  BeltBackTransform inverts
+            // build_forward_transform() which DOES NOT include this per-object
+            // Z-shift (it's not known until vertex scan time).  Result: G-code
+            // coords emerge offset by the un-undone Z-shift — the inverse rotation
+            // couples slicer_z back into both machine_y and machine_z.  Compensating
+            // layer.print_z by belt_z_shift here makes the back-transform produce
+            // correct machine-frame coordinates whether or not a global mode is active.
+            double belt_surface_z = BeltTransformPipeline::has_preslice_remap(pcfg)
+                ? BeltTransformPipeline::remap_bbox(*this->model_object(), pcfg).min.z() : 0.;
+            // The compensation must mirror the Z-shift actually applied, which
+            // is max(0, -m_belt_min_z): when the transformed mesh starts ABOVE
+            // slicer Z=0 (m_belt_min_z > 0 — possible for counter-rotated or
+            // asymmetric geometry whose centered-frame minimum lands positive)
+            // no lift was applied, and an unclamped m_belt_min_z here would
+            // leak straight into the layer Z values, floating the whole object
+            // off the belt by exactly that amount.
+            double belt_z_shift = std::min(m_belt_min_z, 0.) - belt_surface_z;
+            double global_z_offset = belt_z_shift;
+
+            // Centering correction: trafo_centered pretranslates by
+            // -m_center_offset.{x,y}.  Under the belt forward transform, the
+            // Y component of that pretranslate couples into slicer-Z (shear:
+            // tan*c.y, rotation: sin*c.y).  BeltBackTransform inverts the
+            // rotation/shear but doesn't undo centering, so this Z component
+            // leaks into machine output as a position offset whenever
+            // m_center_offset != 0.  When a user moves a volume within an
+            // assembly such that the combined bbox center shifts, this shows
+            // up as a small Z translation in the print.  Compensate by adding
+            // the Z component of the centering through the forward transform.
+            {
+                Transform3d T_fwd = BeltTransformPipeline::build_forward_transform(pcfg);
+                Vec3d c_off(unscale<double>(m_center_offset.x()),
+                            unscale<double>(m_center_offset.y()),
+                            0.);
+                double centering_z_corr = (T_fwd.linear() * c_off).z();
+                global_z_offset += centering_z_corr;
+                BOOST_LOG_TRIVIAL(trace) << "[BELT-DEBUG] centering correction"
+                    << " obj=" << this->model_object()->name
+                    << " m_center_offset_mm=(" << c_off.x() << "," << c_off.y() << ")"
+                    << " centering_z_corr=" << centering_z_corr
+                    << " (added to global_z_offset)";
+            }
+
+            // [BELT-DEBUG] Per-object summary so Case A vs Case B can be compared
+            // side-by-side.  Lays out every value that feeds into the final layer
+            // print_z adjustment.
+            {
+                BoundingBoxf3 raw_bb = this->model_object()->raw_bounding_box();
+                BOOST_LOG_TRIVIAL(trace) << "[BELT-DEBUG] slice() per-object summary"
+                    << " obj=" << this->model_object()->name
+                    << " n_volumes=" << this->model_object()->volumes.size()
+                    << " raw_bbox.min=(" << raw_bb.min.x() << "," << raw_bb.min.y() << "," << raw_bb.min.z() << ")"
+                    << " raw_bbox.max=(" << raw_bb.max.x() << "," << raw_bb.max.y() << "," << raw_bb.max.z() << ")"
+                    << " raw_bbox.center=(" << raw_bb.center().x() << "," << raw_bb.center().y() << ")"
+                    << " m_center_offset=(" << unscale<double>(m_center_offset.x()) << "," << unscale<double>(m_center_offset.y()) << ")"
+                    << " inst_shift=(" << unscale<double>(inst_shift.x()) << "," << unscale<double>(inst_shift.y()) << ")"
+                    << " m_belt_min_z=" << m_belt_min_z
+                    << " belt_surface_z=" << belt_surface_z
+                    << " belt_z_shift=" << belt_z_shift;
+                // Per-volume bbox + get_matrix translation so order/composition is visible.
+                int vi = 0;
+                for (const ModelVolume *mv : this->model_object()->volumes) {
+                    if (!mv->is_model_part()) { ++vi; continue; }
+                    BoundingBoxf3 vol_bb = mv->mesh().transformed_bounding_box(mv->get_matrix());
+                    BOOST_LOG_TRIVIAL(trace) << "[BELT-DEBUG]   vol[" << vi
+                        << "] id=" << mv->id().id << " name='" << mv->name << "'"
+                        << " get_matrix.translation=(" << mv->get_matrix().translation().x() << "," << mv->get_matrix().translation().y() << "," << mv->get_matrix().translation().z() << ")"
+                        << " object_bbox.min=(" << vol_bb.min.x() << "," << vol_bb.min.y() << "," << vol_bb.min.z() << ")"
+                        << " object_bbox.max=(" << vol_bb.max.x() << "," << vol_bb.max.y() << "," << vol_bb.max.z() << ")";
+                    ++vi;
+                }
+            }
+
+            if (pcfg.belt_preslice_global.value) {
+                // Global pre-slice mode: compute full correction c = (T.linear() - I) * d
+                // where T is the belt forward transform and d is the bed position.
+                Transform3d T = BeltTransformPipeline::build_forward_transform(pcfg);
+                Vec3d d(unscale<double>(inst_shift.x()), unscale<double>(inst_shift.y()), 0.);
+                Vec3d c = T.linear() * d - d;
+                global_z_offset += c.z();
+                BOOST_LOG_TRIVIAL(trace) << "[BELTRACE] write m_belt_global_xy_correction tid=" << std::this_thread::get_id()
+                    << " obj=" << this << " old=(" << m_belt_global_xy_correction.x() << "," << m_belt_global_xy_correction.y()
+                    << ") new=(" << c.x() << "," << c.y() << ")";
+                m_belt_global_xy_correction = Vec2d(c.x(), c.y());
+
+                BOOST_LOG_TRIVIAL(trace) << "Belt preslice_global: correction=("
+                    << c.x() << ", " << c.y() << ", " << c.z() << ")"
+                    << " belt_z_shift=" << belt_z_shift << " (m_belt_min_z=" << m_belt_min_z << ")";
+            } else {
+                // Slicing rotation in global mode: bed-position-dependent Z offset.
+                // For R(α, X): c.z = sin(α)*d.y so objects at different bed-Y
+                // values print at different machine Z values along the inclined belt.
+                if (pcfg.belt_slice_rotation_global.value
+                    && pcfg.belt_slice_rotation.value != BeltRotationAxis::None
+                    && std::abs(pcfg.belt_slice_rotation_angle.value) > EPSILON) {
+                    Transform3d T = BeltTransformPipeline::build_forward_transform(pcfg);
+                    Vec3d d(unscale<double>(inst_shift.x()), unscale<double>(inst_shift.y()), 0.);
+                    Vec3d c = T.linear() * d - d;
+                    global_z_offset += c.z();
+                    m_belt_global_xy_correction = Vec2d(c.x(), c.y());
+                }
+
+                // Pre-slice remap global mode: when on, the remap accounts for the
+                // instance bed position. The Z component of the correction
+                // (R - I) * d shifts layer print_z so e.g. a Y↔Z swap with an
+                // object at Y=50 prints at Z=50.
+                if (pcfg.preslice_remap_global.value
+                    && BeltTransformPipeline::has_preslice_remap(pcfg)) {
+                    Transform3d R = BeltTransformPipeline::build_preslice_remap(pcfg);
+                    Vec3d d(unscale<double>(inst_shift.x()), unscale<double>(inst_shift.y()), 0.);
+                    Vec3d remap_correction = R.linear() * d - d;
+                    global_z_offset += remap_correction.z();
+                }
+            }
+
+            BOOST_LOG_TRIVIAL(trace) << "Belt global: z_offset=" << global_z_offset
+                << " (relative to min across " << this->print()->objects().size() << " objects)";
+            BOOST_LOG_TRIVIAL(trace) << "[BELTRACE] write m_belt_global_z_offset tid=" << std::this_thread::get_id()
+                << " obj=" << this << " old=" << m_belt_global_z_offset << " new=" << global_z_offset;
+            m_belt_global_z_offset = global_z_offset;
+            // [BELT-DEBUG] Final breakdown of all contributions to layer.print_z
+            // and where the first / last layer end up post-adjustment.
+            BOOST_LOG_TRIVIAL(trace) << "[BELT-DEBUG] global_z_offset breakdown"
+                << " obj=" << this->model_object()->name
+                << " belt_z_shift=" << belt_z_shift
+                << " total_global_z_offset=" << global_z_offset
+                << " xy_correction=(" << m_belt_global_xy_correction.x() << "," << m_belt_global_xy_correction.y() << ")"
+                << " belt_floor_z_shift_before=" << (m_slicing_params.belt_floor_z_shift)
+                << " n_layers=" << m_layers.size();
+            if (std::abs(global_z_offset) > EPSILON) {
+                for (Layer *layer : m_layers)
+                    layer->print_z += global_z_offset;
+                // Keep belt floor clipping in sync with the shifted print_z
+                // values — the support generator sees globally-offset object
+                // layer print_z, so belt_floor_z_shift must match.
+                m_slicing_params.belt_floor_z_shift += global_z_offset;
+            }
+            if (!m_layers.empty()) {
+                BOOST_LOG_TRIVIAL(trace) << "[BELT-DEBUG]   post-adjustment"
+                    << " first_layer.print_z=" << m_layers.front()->print_z
+                    << " last_layer.print_z=" << m_layers.back()->print_z
+                    << " belt_floor_z_shift_after=" << m_slicing_params.belt_floor_z_shift;
+            }
+            if (!m_layers.empty()) {
+                BOOST_LOG_TRIVIAL(trace) << "Belt global: first_layer_z=" << m_layers.front()->print_z
+                    << " last_layer_z=" << m_layers.back()->print_z
+                    << " num_layers=" << m_layers.size()
+                    << " center_offset=(" << unscale<double>(m_center_offset.x())
+                    << ", " << unscale<double>(m_center_offset.y()) << ")";
+            }
+
+            // Cache the final patched belt_floor_z_shift so a later support-only
+            // invalidation can rebuild m_slicing_params without losing this exact
+            // (vertex-scan-derived) value.  update_slicing_parameters() will
+            // restore it after create_from_config() seeds the bbox approximation.
+            m_belt_floor_z_shift_cached      = m_slicing_params.belt_floor_z_shift;
+            m_belt_floor_z_shift_cache_valid = true;
+        }
+    }
+
     // BBS
+    BOOST_LOG_TRIVIAL(trace) << "[BELTRACE] slice EXIT tid=" << std::this_thread::get_id() << " obj=" << this
+        << " layers=" << m_layers.size() << " belt_min_z=" << m_belt_min_z
+        << " belt_global_z_offset=" << m_belt_global_z_offset
+        << " belt_xy=(" << m_belt_global_xy_correction.x() << "," << m_belt_global_xy_correction.y() << ")";
     this->set_done(posSlice);
 }
 
@@ -1144,6 +1399,7 @@ void apply_fuzzy_skin_segmentation(PrintObject &print_object, ThrowOnCancel thro
     }); // end of parallel_for
 }
 
+
 // 1) Decides Z positions of the layers,
 // 2) Initializes layers and their regions
 // 3) Slices the object meshes
@@ -1177,7 +1433,8 @@ void PrintObject::slice_volumes()
     if (!slice_zs.empty()) {
         objSliceByVolume = slice_volumes_inner(
             print->config(), this->config(), this->trafo_centered(),
-            this->model_object()->volumes, m_shared_regions->layer_ranges, slice_zs, throw_on_cancel_callback);
+            this->model_object()->volumes, m_shared_regions->layer_ranges, slice_zs, throw_on_cancel_callback,
+            &m_belt_min_z);
     }
 
     //BBS: "model_part" volumes are grouded according to their connections

src/libslic3r/Slicing.hpp

@@ -111,6 +111,13 @@ struct SlicingParameters
      coordf_t     object_print_z_uncompensated_max { 0 };
      // Scaling factor for compensating shrinkage in Z-axis.
      coordf_t    object_shrinkage_compensation_z { 0 };
+
+    // Belt printer: floor plane parameters for support clipping.
+    // Belt contact surface in slicing coords: Z = bb_min_z + sf*Y + slicing_z_shift.
+    // cutoff = (print_z - belt_floor_z_shift - floor_offset) / shear_factor
+    double      belt_floor_shear_factor { 0.0 };  // shear factor (e.g. cot(45deg))
+    int         belt_floor_from_axis { 1 };        // which axis the shear is from (0=X, 1=Y)
+    double      belt_floor_z_shift { 0.0 };        // bb_min_z + max(0, -min_z_after_shear)
 };
 static_assert(IsTriviallyCopyable<SlicingParameters>::value, "SlicingParameters class is not POD (and it should be - see constructor).");
 

src/libslic3r/Support/BeltFloorContext.cpp

@@ -0,0 +1,124 @@
+#include "BeltFloorContext.hpp"
+
+#include <cmath>
+#include <limits>
+
+namespace Slic3r {
+
+bool BeltFloorContext::init(const SlicingParameters &sp, const PrintConfig &pcfg)
+{
+    m_active = false;
+    m_shear_factor = sp.belt_floor_shear_factor;
+    m_from_axis    = sp.belt_floor_from_axis;
+    m_z_shift      = sp.belt_floor_z_shift;
+    m_floor_offset = pcfg.belt_support_floor_offset.value;
+
+    if (std::abs(m_shear_factor) < EPSILON)
+        return false;
+
+    m_active = true;
+    return true;
+}
+
+bool BeltFloorContext::init_local(const SlicingParameters &sp, const PrintConfig &pcfg,
+                                  double global_z_offset)
+{
+    if (!init(sp, pcfg))
+        return false;
+    // Local Z: subtract the global Z offset so polygon computation
+    // works in the object's local coordinate space.
+    m_z_shift -= global_z_offset;
+    return true;
+}
+
+Polygons BeltFloorContext::surface_polygon(coordf_t print_z) const
+{
+    return half_plane(print_z, /*belt_surface=*/true);
+}
+
+Polygons BeltFloorContext::valid_region_polygon(coordf_t print_z) const
+{
+    return half_plane(print_z, /*belt_surface=*/false);
+}
+
+double BeltFloorContext::floor_print_z(const Point &pos_slicing) const
+{
+    if (!m_active)
+        return -std::numeric_limits<double>::infinity();
+    double pos = unscale<double>(m_from_axis == 0 ? pos_slicing.x() : pos_slicing.y());
+    return m_shear_factor * pos + m_floor_offset + m_z_shift;
+}
+
+std::vector<Polygons> BeltFloorContext::compute_per_layer_floors(
+    size_t num_layers,
+    const std::function<double(size_t)> &layer_print_z) const
+{
+    std::vector<Polygons> result(num_layers);
+    if (!m_active)
+        return result;
+    for (size_t i = 0; i < num_layers; ++i)
+        result[i] = surface_polygon(layer_print_z(i));
+    return result;
+}
+
+Polygons BeltFloorContext::half_plane(coordf_t print_z, bool belt_surface) const
+{
+    if (!m_active)
+        return {};
+
+    const double cutoff = this->cutoff_u(print_z);
+    const coord_t cutoff_scaled = scale_(cutoff);
+    const coord_t large_bound   = scale_(1e3);
+
+    // The belt surface is on one side of the cutoff line; the valid region
+    // is on the other side.  Which side depends on shear_factor sign.
+    //
+    // belt_surface=true  → the belt side (where support should NOT exist)
+    // belt_surface=false → the valid side (where support IS allowed)
+    //
+    // For shear_factor > 0: belt surface is from_axis >= cutoff
+    // For shear_factor < 0: belt surface is from_axis <= cutoff
+    bool high_side = (m_shear_factor > 0) == belt_surface;
+
+    Polygon poly;
+    if (m_from_axis == 0) {
+        if (high_side) {
+            // X >= cutoff
+            poly.points = {
+                Point(cutoff_scaled, -large_bound),
+                Point(large_bound,   -large_bound),
+                Point(large_bound,    large_bound),
+                Point(cutoff_scaled,  large_bound)
+            };
+        } else {
+            // X < cutoff
+            poly.points = {
+                Point(-large_bound,  -large_bound),
+                Point(cutoff_scaled, -large_bound),
+                Point(cutoff_scaled,  large_bound),
+                Point(-large_bound,   large_bound)
+            };
+        }
+    } else {
+        if (high_side) {
+            // Y >= cutoff
+            poly.points = {
+                Point(-large_bound, cutoff_scaled),
+                Point( large_bound, cutoff_scaled),
+                Point( large_bound, large_bound),
+                Point(-large_bound, large_bound)
+            };
+        } else {
+            // Y < cutoff
+            poly.points = {
+                Point(-large_bound, -large_bound),
+                Point( large_bound, -large_bound),
+                Point( large_bound, cutoff_scaled),
+                Point(-large_bound, cutoff_scaled)
+            };
+        }
+    }
+    return { poly };
+}
+
+} // namespace Slic3r

src/libslic3r/Support/BeltFloorContext.hpp

@@ -0,0 +1,80 @@
+#pragma once
+
+#include "../libslic3r.h"
+#include "../Point.hpp"
+#include "../Polygon.hpp"
+#include "../Slicing.hpp"
+#include "../PrintConfig.hpp"
+
+namespace Slic3r {
+
+class PrintObject;
+
+// Belt floor context: encapsulates the parameters and polygon computation
+// for belt printer floor clipping in support generation.
+//
+// All belt floor code across SupportMaterial, TreeSupport, TreeSupport3D,
+// and TreeModelVolumes uses the same 4 parameters and the same 4-case
+// polygon construction.  This class consolidates that logic.
+//
+// Construct once per PrintObject, then call surface_polygon() or
+// valid_region_polygon() per layer with the layer's print_z.
+class BeltFloorContext
+{
+public:
+    BeltFloorContext() = default;
+
+    // Initialize from slicing parameters and print config.
+    // Uses global Z coordinates (for SupportMaterial, non-organic TreeSupport).
+    bool init(const SlicingParameters &sp, const PrintConfig &pcfg);
+
+    // Initialize with a Z offset subtracted from z_shift.
+    // Uses local Z coordinates (for TreeSupport3D, TreeModelVolumes organic pipeline).
+    bool init_local(const SlicingParameters &sp, const PrintConfig &pcfg,
+                    double global_z_offset);
+
+    bool is_active() const { return m_active; }
+
+    // Compute the belt-side half-plane polygon at a given print_z.
+    // This is the region where the belt surface exists.
+    Polygons surface_polygon(coordf_t print_z) const;
+
+    // Compute the valid-region half-plane polygon at a given print_z.
+    // This is the complement: the region where support is allowed.
+    Polygons valid_region_polygon(coordf_t print_z) const;
+
+    // Compute the belt floor Z position at a given XY position (in slicing coords).
+    // Returns -infinity if not active.
+    double floor_print_z(const Point &pos_slicing) const;
+
+    // The from_axis coordinate (unscaled, slicing frame) where the belt surface
+    // crosses a horizontal plane at print_z.  Inverse of floor_print_z() along
+    // the shear axis.  Only meaningful when is_active().
+    coordf_t cutoff_u(coordf_t print_z) const
+        { return (print_z - m_z_shift - m_floor_offset) / m_shear_factor; }
+
+    // Pre-compute belt floor polygons for a range of layers.
+    // layer_print_z(i) returns the print_z for layer index i.
+    std::vector<Polygons> compute_per_layer_floors(
+        size_t num_layers,
+        const std::function<double(size_t)> &layer_print_z) const;
+
+    // Accessors
+    double shear_factor()  const { return m_shear_factor; }
+    int    from_axis()     const { return m_from_axis; }
+    double z_shift()       const { return m_z_shift; }
+    double floor_offset()  const { return m_floor_offset; }
+
+private:
+    bool   m_active       = false;
+    double m_shear_factor = 0.0;
+    int    m_from_axis    = 1;  // 0=X, 1=Y
+    double m_z_shift      = 0.0;
+    double m_floor_offset = 0.0;
+
+    // Internal: compute the raw half-plane polygon.
+    // If belt_surface=true, returns the belt side; otherwise the valid (complement) side.
+    Polygons half_plane(coordf_t print_z, bool belt_surface) const;
+};
+
+} // namespace Slic3r

src/libslic3r/Support/SupportCommon.cpp

@@ -270,7 +270,9 @@ SupportGeneratorLayersPtr generate_raft_base(
         // The object does not have a raft.
         // Calculate the area covered by the brim.
         const BrimType brim_type       = object.config().brim_type;
-        const bool     brim_outer      = brim_type == btOuterOnly || brim_type == btOuterAndInner;
+        // btLeadingEdgeOnly only means anything on a belt printer, where this code path
+        // does not run; elsewhere it degrades to an outer brim (see Brim.cpp).
+        const bool     brim_outer      = brim_type == btOuterOnly || brim_type == btOuterAndInner || brim_type == btLeadingEdgeOnly;
         const bool     brim_inner      = brim_type == btInnerOnly || brim_type == btOuterAndInner;
         // BBS: the pattern of raft and brim are the same, thus the brim can be serpated by support raft.
         const auto     brim_object_gap = scaled<float>(object.config().brim_object_gap.value);
@@ -1802,7 +1804,14 @@ void generate_support_toolpaths(
                 bool  sheath  = support_params.with_sheath;
                 bool  no_sort = false;
                 bool  done    = false;
-                if (base_layer.layer->bottom_z < EPSILON) {
+                // Belt printers have no flat bed first layer — the belt is the tilted
+                // build surface — so the dense raft_first_layer_density flange must not
+                // fire anywhere, including the layer at z=0 (the belt-surface line).
+                // (belt_floor_shear_factor is non-zero only when belt_printer is on.)
+                // For every other printer type, support z is never negative, so this
+                // matches the original "first layer at z=0" behaviour unchanged.
+                const bool is_belt_printer = std::abs(slicing_params.belt_floor_shear_factor) > EPSILON;
+                if (! is_belt_printer && base_layer.layer->bottom_z < EPSILON) {
                     // Base flange (the 1st layer).
                     filler = filler_first_layer;
                     filler->angle = Geometry::deg2rad(float(config.support_angle.value + 90.));

src/libslic3r/Support/SupportCommon.hpp

@@ -144,6 +144,12 @@ int idx_lower_or_equal(const std::vector<T*> &vec, int idx, FN_LOWER_EQUAL fn_lo
     return idx_lower_or_equal(vec.begin(), vec.end(), idx, fn_lower_equal);
 }
 
+// Belt floor: compute the belt-side half-plane polygon at a given print_z.
+// Used to clip support polygons against the belt surface.
+Polygons belt_floor_surface_polygon(
+    const SlicingParameters &slicing_params, const PrintConfig &print_config,
+    const PrintObject &object, coordf_t print_z);
+
 } // namespace Slic3r
 
 #endif /* slic3r_SupportCommon_hpp_ */

src/libslic3r/Support/SupportMaterial.cpp

@@ -5,6 +5,7 @@
 #include "Print.hpp"
 #include "SupportMaterial.hpp"
 #include "SupportCommon.hpp"
+#include "BeltFloorContext.hpp"
 #include "Geometry.hpp"
 #include "Point.hpp"
 #include "MutablePolygon.hpp"
@@ -366,10 +367,21 @@ inline void layers_append(SupportGeneratorLayersPtr &dst, const SupportGenerator
 }
 
 // Support layer that is covered by some form of dense interface.
-static constexpr const std::initializer_list<SupporLayerType> support_types_interface { 
+static constexpr const std::initializer_list<SupporLayerType> support_types_interface {
     SupporLayerType::RaftInterface, SupporLayerType::BottomContact, SupporLayerType::BottomInterface, SupporLayerType::TopContact, SupporLayerType::TopInterface
 };
 
+// Forward declarations for belt floor helpers (defined later in this file).
+// belt_floor_surface_polygon is declared in SupportCommon.hpp (non-static,
+// shared with TreeSupport.cpp).
+
+static Polygons belt_floor_valid_region_polygon(
+    const SlicingParameters &slicing_params, const PrintConfig &print_config,
+    const PrintObject &object, coordf_t print_z);
+static void trim_support_layers_by_belt_floor(
+    const SlicingParameters &slicing_params, const PrintConfig &print_config,
+    const PrintObject &object, SupportGeneratorLayersPtr &support_layers);
+
 void PrintObjectSupportMaterial::generate(PrintObject &object)
 {
     BOOST_LOG_TRIVIAL(info) << "Support generator - Start";
@@ -442,11 +454,12 @@ void PrintObjectSupportMaterial::generate(PrintObject &object)
         object, bottom_contacts, top_contacts, layer_storage);
 
     this->trim_support_layers_by_object(object, top_contacts, m_slicing_params.gap_support_object, m_slicing_params.gap_object_support, m_support_params.gap_xy);
+    trim_support_layers_by_belt_floor(m_slicing_params, *m_print_config, object, top_contacts);
 
 #ifdef SLIC3R_DEBUG
     for (const SupportGeneratorLayer *layer : top_contacts)
         Slic3r::SVG::export_expolygons(
-            debug_out_path("support-top-contacts-trimmed-by-object-%d-%lf.svg", iRun, layer->print_z), 
+            debug_out_path("support-top-contacts-trimmed-by-object-%d-%lf.svg", iRun, layer->print_z),
             union_ex(layer->polygons));
 #endif
 
@@ -602,6 +615,37 @@ Polygons collect_region_slices_by_type(const Layer &layer, SurfaceType surface_t
     return out;
 }
 
+// Belt printer: compute the belt-side half-plane polygon at a given print_z.
+// This represents the region where the belt surface exists (the "phantom top surface").
+// Support that overlaps with this polygon should terminate with a bottom contact.
+// Returns empty if belt floor is not active.
+Polygons belt_floor_surface_polygon(
+    const SlicingParameters &slicing_params,
+    const PrintConfig       &print_config,
+    const PrintObject       &object,
+    coordf_t                 print_z)
+{
+    BeltFloorContext ctx;
+    if (!ctx.init(slicing_params, print_config))
+        return {};
+    return ctx.surface_polygon(print_z);
+}
+
+// Belt printer: compute the valid-region half-plane polygon at a given print_z.
+// This is the region where support is allowed to exist (above the belt).
+// Used to clip the downward-propagating support projection.
+static Polygons belt_floor_valid_region_polygon(
+    const SlicingParameters &slicing_params,
+    const PrintConfig       &print_config,
+    const PrintObject       &object,
+    coordf_t                 print_z)
+{
+    BeltFloorContext ctx;
+    if (!ctx.init(slicing_params, print_config))
+        return {};
+    return ctx.valid_region_polygon(print_z);
+}
+
 // Collect outer contours of all slices of this layer.
 // This is useful for calculating the support base with holes filled.
 Polygons collect_slices_outer(const Layer &layer)
@@ -1393,6 +1437,10 @@ static inline ExPolygons detect_overhangs(
     const double threshold_rad = Geometry::deg2rad(thresh_angle);
     const bool bridge_no_support = object_config.bridge_no_support.value;
     const coordf_t xy_expansion = scale_(object_config.support_expansion.value);
+    // Build plate tilt: compute per-layer XY shift for tilted gravity direction
+    const double tilt_x_rad = Geometry::deg2rad(print_config.build_plate_tilt_x.value);
+    const double tilt_y_rad = Geometry::deg2rad(print_config.build_plate_tilt_y.value);
+    const bool   has_tilt   = std::abs(tilt_x_rad) > EPSILON || std::abs(tilt_y_rad) > EPSILON;
     float lower_layer_offset = 0;
 
     if (layer_id == 0)
@@ -1426,6 +1474,19 @@ static inline ExPolygons detect_overhangs(
             }
         }
 
+        // Apply build plate tilt: shift lower layer polygons to simulate tilted gravity.
+        // This is loop-invariant across regions, so compute it once here.
+        const Polygons *effective_lower = &lower_layer_polygons;
+        Polygons tilted_lower;
+        if (has_tilt) {
+            tilted_lower = lower_layer_polygons;
+            const double lh = lower_layer.height;
+            Point tilt_shift(coord_t(scale_(lh * tan(tilt_y_rad))),
+                             coord_t(scale_(lh * tan(tilt_x_rad))));
+            translate(tilted_lower, tilt_shift);
+            effective_lower = &tilted_lower;
+        }
+
         for (LayerRegion *layerm : layer.regions()) {
             // Extrusion width accounts for the roundings of the extrudates.
             // It is the maximum widh of the extrudate.
@@ -1444,7 +1505,7 @@ static inline ExPolygons detect_overhangs(
             Polygons layerm_polygons = to_polygons(layerm->slices.surfaces);
             if (lower_layer_offset == 0.f) {
                 // Support everything.
-                diff_polygons = diff(layerm_polygons, lower_layer_polygons);
+                diff_polygons = diff(layerm_polygons, *effective_lower);
                 if (buildplate_only) {
                     // Don't support overhangs above the top surfaces.
                     // This step is done before the contact surface is calculated by growing the overhang region.
@@ -1453,9 +1514,9 @@ static inline ExPolygons detect_overhangs(
             } else if (auto_normal_support) {
                 // Get the regions needing a suport, collapse very tiny spots.
                 //FIXME cache the lower layer offset if this layer has multiple regions.
-                diff_polygons = 
+                diff_polygons =
                     diff(layerm_polygons,
-                            expand(lower_layer_polygons, lower_layer_offset, SUPPORT_SURFACES_OFFSET_PARAMETERS));
+                            expand(*effective_lower, lower_layer_offset, SUPPORT_SURFACES_OFFSET_PARAMETERS));
                 if (buildplate_only && ! annotations.buildplate_covered[layer_id].empty()) {
                     // Don't support overhangs above the top surfaces.
                     // This step is done before the contact surface is calculated by growing the overhang region.
@@ -1463,9 +1524,9 @@ static inline ExPolygons detect_overhangs(
                 }
                 if (! diff_polygons.empty()) {
                     // Offset the support regions back to a full overhang, restrict them to the full overhang.
-                    // This is done to increase size of the supporting columns below, as they are calculated by 
+                    // This is done to increase size of the supporting columns below, as they are calculated by
                     // propagating these contact surfaces downwards.
-                    diff_polygons = diff(intersection(expand(diff_polygons, lower_layer_offset, SUPPORT_SURFACES_OFFSET_PARAMETERS), layerm_polygons), lower_layer_polygons);
+                    diff_polygons = diff(intersection(expand(diff_polygons, lower_layer_offset, SUPPORT_SURFACES_OFFSET_PARAMETERS), layerm_polygons), *effective_lower);
                 }
                 //FIXME add user defined filtering here based on minimal area or minimum radius or whatever.
 
@@ -2505,6 +2566,82 @@ static inline SupportGeneratorLayer* detect_bottom_contacts(
     return &layer_new;
 }
 
+// Belt printer: detect bottom contacts where support meets the belt floor plane.
+// Modeled on detect_bottom_contacts() but uses the belt plane polygon instead of stTop surfaces.
+static inline SupportGeneratorLayer* detect_belt_floor_bottom_contacts(
+    const SlicingParameters                          &slicing_params,
+    const SupportParameters                          &support_params,
+    const PrintConfig                                &print_config,
+    const PrintObject                                &object,
+    const Layer                                      &layer,
+    // Existing top contact layers, for snapping.
+    const SupportGeneratorLayersPtr                  &top_contacts,
+    size_t                                            contact_idx,
+    SupportGeneratorLayerStorage                     &layer_storage,
+    std::vector<Polygons>                            &layer_support_areas,
+    const Polygons                                   &supports_projected)
+{
+    // Compute the belt surface polygon at this layer's Z.
+    Polygons belt_surface = belt_floor_surface_polygon(slicing_params, print_config, object, layer.print_z);
+    if (belt_surface.empty())
+        return nullptr;
+
+    // Find where projected support overlaps the belt surface.
+    Polygons touching = intersection(belt_surface, supports_projected);
+    if (touching.empty())
+        return nullptr;
+
+    assert(layer.id() >= slicing_params.raft_layers());
+    size_t layer_id = layer.id() - slicing_params.raft_layers();
+
+    // Allocate a new bottom contact layer resting on the belt plane.
+    SupportGeneratorLayer &layer_new = layer_storage.allocate_unguarded(SupporLayerType::BottomContact);
+
+    // No object layer to sync with -- compute heights directly from flow parameters.
+    layer_new.height  = support_params.support_material_bottom_interface_flow.height();
+    layer_new.print_z = layer.print_z + layer_new.height + slicing_params.gap_object_support;
+    layer_new.bottom_z = layer.print_z;
+    layer_new.idx_object_layer_below = layer_id;
+    layer_new.bridging = ! slicing_params.zero_gap_interface_bottom && object.config().thick_bridges;
+    layer_new.polygons = expand(touching, float(support_params.support_material_flow.scaled_width()), SUPPORT_SURFACES_OFFSET_PARAMETERS);
+
+    if (! slicing_params.zero_gap_interface_bottom) {
+        // Snap to nearby top contact layers to avoid very thin support layers.
+        for (size_t top_idx = size_t(std::max<int>(0, int(contact_idx)));
+            top_idx < top_contacts.size() && top_contacts[top_idx]->print_z < layer_new.print_z + support_params.support_layer_height_min + EPSILON;
+            ++ top_idx) {
+            if (top_contacts[top_idx]->print_z > layer_new.print_z - support_params.support_layer_height_min - EPSILON) {
+                coordf_t diff = layer_new.print_z - top_contacts[top_idx]->print_z;
+                assert(std::abs(diff) <= support_params.support_layer_height_min + EPSILON);
+                if (diff > 0.F) {
+                    if (layer_new.height - diff > support_params.support_layer_height_min) {
+                        layer_new.print_z = top_contacts[top_idx]->print_z;
+                        layer_new.height -= diff;
+                    } else {
+                        continue;
+                    }
+                } else {
+                    layer_new.print_z = top_contacts[top_idx]->print_z;
+                    layer_new.height -= diff;
+                }
+                break;
+            }
+        }
+    }
+
+    // Trim the already created base layers above this belt contact.
+    touching = expand(touching, float(SCALED_EPSILON));
+    for (int layer_id_above = int(layer_id) + 1; layer_id_above < int(object.total_layer_count()); ++ layer_id_above) {
+        const Layer &layer_above = *object.layers()[layer_id_above];
+        if (layer_above.print_z > layer_new.print_z - EPSILON)
+            break;
+        if (Polygons &above = layer_support_areas[layer_id_above]; ! above.empty())
+            above = diff(above, touching);
+    }
+
+    return &layer_new;
+}
+
 // Returns polygons to print + polygons to propagate downwards.
 // Called twice: First for normal supports, possibly trimmed by "on build plate only", second for support enforcers not trimmed by "on build plate only".
 static inline std::pair<Polygons, Polygons> project_support_to_grid(const Layer &layer, const SupportGridParams &grid_params, const Polygons &overhangs, Polygons *layer_buildplate_covered
@@ -2604,6 +2741,8 @@ SupportGeneratorLayersPtr PrintObjectSupportMaterial::bottom_contact_layers_and_
     //const auto   expansion_to_slice = m_support_material_flow.scaled_spacing() / 2 + 25;
     const SupportGridParams grid_params(*m_object_config, m_support_params.support_material_flow);
     const bool buildplate_only = ! buildplate_covered.empty();
+    const bool has_belt_floor  = std::abs(m_slicing_params.belt_floor_shear_factor) > EPSILON
+        && m_print_config->belt_support_floor_mode.value == BeltSupportFloorMode::GeneratorOnly;
 
     // Allocate empty surface areas, one per object layer.
     layer_support_areas.assign(object.total_layer_count(), Polygons());
@@ -2664,8 +2803,9 @@ SupportGeneratorLayersPtr PrintObjectSupportMaterial::bottom_contact_layers_and_
         tbb::task_group task_group;
         const Polygons &overhangs_for_bottom_contacts = buildplate_only ? enforcers_projection_raw : overhangs_projection_raw;
         if (! overhangs_for_bottom_contacts.empty())
-            // Find the bottom contact layers above the top surfaces of this layer.
+            // Find the bottom contact layers above the top surfaces of this layer,
-            task_group.run([this, &object, &layer, &top_contacts, contact_idx, &layer_storage, &layer_support_areas, &bottom_contacts, &overhangs_for_bottom_contacts
+            // and also detect belt floor contacts if belt mode is active.
+            task_group.run([this, &object, &layer, &top_contacts, contact_idx, &layer_storage, &layer_support_areas, &bottom_contacts, &overhangs_for_bottom_contacts, has_belt_floor
     #ifdef SLIC3R_DEBUG
                 , iRun, &polygons_new
     #endif // SLIC3R_DEBUG
@@ -2679,6 +2819,15 @@ SupportGeneratorLayersPtr PrintObjectSupportMaterial::bottom_contact_layers_and_
                     );
                     if (layer_new)
                         bottom_contacts.push_back(layer_new);
+                    // Belt floor phantom surface: detect where support meets the belt plane.
+                    if (has_belt_floor) {
+                        SupportGeneratorLayer *belt_layer = detect_belt_floor_bottom_contacts(
+                            m_slicing_params, m_support_params, *m_print_config, object,
+                            layer, top_contacts, contact_idx, layer_storage,
+                            layer_support_areas, overhangs_for_bottom_contacts);
+                        if (belt_layer)
+                            bottom_contacts.push_back(belt_layer);
+                    }
                 });
 
         Polygons &layer_support_area = layer_support_areas[layer_id];
@@ -2717,6 +2866,23 @@ SupportGeneratorLayersPtr PrintObjectSupportMaterial::bottom_contact_layers_and_
 
         task_group.wait();
 
+        // Belt floor: clip projections and support areas so support doesn't
+        // propagate below the belt plane.
+        if (has_belt_floor) {
+            Polygons valid_region = belt_floor_valid_region_polygon(
+                m_slicing_params, *m_print_config, object, layer.print_z);
+            if (! valid_region.empty()) {
+                if (! overhangs_projection.empty())
+                    overhangs_projection = intersection(overhangs_projection, valid_region);
+                if (! enforcers_projection.empty())
+                    enforcers_projection = intersection(enforcers_projection, valid_region);
+                if (! layer_support_area.empty())
+                    layer_support_area = intersection(layer_support_area, valid_region);
+                if (! layer_support_area_enforcers.empty())
+                    layer_support_area_enforcers = intersection(layer_support_area_enforcers, valid_region);
+            }
+        }
+
         if (! layer_support_area_enforcers.empty()) {
             if (layer_support_area.empty())
                 layer_support_area = std::move(layer_support_area_enforcers);
@@ -2727,6 +2893,7 @@ SupportGeneratorLayersPtr PrintObjectSupportMaterial::bottom_contact_layers_and_
 
     std::reverse(bottom_contacts.begin(), bottom_contacts.end());
     trim_support_layers_by_object(object, bottom_contacts, m_slicing_params.gap_support_object, m_slicing_params.gap_object_support, m_support_params.gap_xy);
+    trim_support_layers_by_belt_floor(m_slicing_params, *m_print_config, object, bottom_contacts);
     return bottom_contacts;
 }
 
@@ -3100,6 +3267,33 @@ void PrintObjectSupportMaterial::generate_base_layers(
 #endif /* SLIC3R_DEBUG */
 
     this->trim_support_layers_by_object(object, intermediate_layers, m_slicing_params.gap_support_object, m_slicing_params.gap_object_support, m_support_params.gap_xy);
+    trim_support_layers_by_belt_floor(m_slicing_params, *m_print_config, object, intermediate_layers);
+}
+
+// Belt printer: trim support layer polygons by the belt floor plane.
+// For each support layer, computes the belt floor half-plane at that layer's print_z
+// and subtracts it from the support polygons. This follows the same diff() pattern
+// as trim_support_layers_by_object() so that interface layers derived from trimmed
+// intermediates automatically inherit the belt floor trimming.
+static void trim_support_layers_by_belt_floor(
+    const SlicingParameters          &slicing_params,
+    const PrintConfig                &print_config,
+    const PrintObject                &object,
+    SupportGeneratorLayersPtr        &support_layers)
+{
+    BeltFloorContext ctx;
+    if (!ctx.init(slicing_params, print_config))
+        return;
+    if (print_config.belt_support_floor_mode.value != BeltSupportFloorMode::GeneratorOnly)
+        return;
+
+    tbb::parallel_for(tbb::blocked_range<size_t>(0, support_layers.size()),
+        [&](const tbb::blocked_range<size_t> &range) {
+            for (size_t i = range.begin(); i < range.end(); ++i)
+                if (support_layers[i])
+                    support_layers[i]->polygons = diff(support_layers[i]->polygons,
+                                                       ctx.surface_polygon(support_layers[i]->print_z));
+        });
 }
 
 void PrintObjectSupportMaterial::trim_support_layers_by_object(