Fix multi-tool standby heaters by turning off unused extruders (#15849)

With ooze prevention on, an extruder that has no layers left is set to 0 °C when it is parked, instead of its standby temperature. On IMEX printers where several filaments share one heater, the heater is only turned off once every filament on it is done.

deps/JPEG/JPEG.cmake

@@ -1,22 +1,7 @@
-if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
-    if (JPEG_VERSION STREQUAL "6")
-        message("Using Jpeg Lib 62")
-        set(jpeg_flag "")
-    elseif (JPEG_VERSION STREQUAL "7")
-        message("Using Jpeg Lib 70")
-        set(jpeg_flag "-DWITH_JPEG7=ON")
-    else ()
-        message("Using Jpeg Lib 80")
-        set(jpeg_flag "-DWITH_JPEG8=ON")
-    endif ()
-endif()
-
 orcaslicer_add_cmake_project(JPEG
-    URL https://github.com/libjpeg-turbo/libjpeg-turbo/archive/refs/tags/3.0.1.zip
-    URL_HASH SHA256=d6d99e693366bc03897677650e8b2dfa76b5d6c54e2c9e70c03f0af821b0a52f
-    DEPENDS ${ZLIB_PKG}
+    URL https://github.com/libjpeg-turbo/libjpeg-turbo/archive/refs/tags/3.2.0.zip
+    URL_HASH SHA256=1b4c2cb6cba1ca5e53b9e85eeeab02154cab4b70894c96e97a9c747a26d19d63
     CMAKE_ARGS
         -DENABLE_SHARED=OFF
         -DENABLE_STATIC=ON
-        ${jpeg_flag}
 )

scripts/flatpak/com.orcaslicer.OrcaSlicer.yml

@@ -336,10 +336,10 @@ modules:
         sha256: 3d22d46c566b1761a0e15ea397589b3a5f36ac09b7c785382e6470156c04247f
         dest: external-packages/PNG
 
-      # libjpeg-turbo 3.0.1
+      # libjpeg-turbo 3.2.0
       - type: file
-        url: https://github.com/libjpeg-turbo/libjpeg-turbo/archive/refs/tags/3.0.1.zip
-        sha256: d6d99e693366bc03897677650e8b2dfa76b5d6c54e2c9e70c03f0af821b0a52f
+        url: https://github.com/libjpeg-turbo/libjpeg-turbo/archive/refs/tags/3.2.0.zip
+        sha256: 1b4c2cb6cba1ca5e53b9e85eeeab02154cab4b70894c96e97a9c747a26d19d63
         dest: external-packages/JPEG
 
       # Freetype 2.12.1

src/libslic3r/GCode.cpp

@@ -432,27 +432,36 @@ static std::vector<Vec2d> get_path_of_change_filament(const Print& print)
 
     std::string OozePrevention::pre_toolchange(GCode& gcodegen)
     {
-        std::string gcode;
-
         unsigned int extruder_id = gcodegen.writer().filament()->id();
-        const auto& filament_idle_temp = gcodegen.config().idle_temperature;
-        if (filament_idle_temp.get_at(extruder_id) == 0) {
-            // There is no idle temperature defined in filament settings.
-            // Use the delta value from print config.
-            if (gcodegen.config().standby_temperature_delta.value != 0) {
-                // we assume that heating is always slower than cooling, so no need to block
-                gcode += gcodegen.writer().set_temperature
-                (this->_get_temp(gcodegen) + gcodegen.config().standby_temperature_delta.value, false, extruder_id);
-                gcode.pop_back();
-                gcode += " ;cooldown\n"; // this is a marker for GCodeProcessor, so it can supress the commands when needed
-            }
-        } else {
-            // Use the value from filament settings. That one is absolute, not delta.
-            gcode += gcodegen.writer().set_temperature(filament_idle_temp.get_at(extruder_id), false, extruder_id);
-            gcode.pop_back();
-            gcode += " ;cooldown\n"; // this is a marker for GCodeProcessor, so it can supress the commands when needed
+
+        // Check if this tool will ever be used again in this print.
+        bool is_last_use = false;
+        if (gcodegen.m_print != nullptr && !gcodegen.m_print->tool_ordering().empty()) {
+            coordf_t current_z        = gcodegen.layer() ? gcodegen.layer()->print_z : gcodegen.writer().get_position().z();
+            const auto& tool_ordering = gcodegen.m_print->tool_ordering();
+            const auto& cfg           = gcodegen.config();
+            const int heater          = imex_physical_heater_for(cfg.is_imex.value, cfg.physical_extruder_map, int(extruder_id));
+            is_last_use               = tool_ordering.is_last_extrusion_layer(current_z, extruder_id);
+            for (unsigned int f : tool_ordering.all_extruders())
+                if (is_last_use && imex_physical_heater_for(cfg.is_imex.value, cfg.physical_extruder_map, int(f)) == heater)
+                    is_last_use = tool_ordering.is_last_extrusion_layer(current_z, f);
         }
 
+        int temp = 0;
+        if (!is_last_use) {
+            const auto& filament_idle_temp = gcodegen.config().idle_temperature;
+            if (filament_idle_temp.get_at(extruder_id) == 0) {
+                if (gcodegen.config().standby_temperature_delta.value == 0)
+                    return std::string();
+                temp = this->_get_temp(gcodegen) + gcodegen.config().standby_temperature_delta.value;
+            } else {
+                temp = filament_idle_temp.get_at(extruder_id);
+            }
+        }
+
+        std::string gcode = gcodegen.writer().set_temperature(temp, false, extruder_id);
+        gcode.pop_back();
+        gcode += " ;cooldown\n"; // this is a marker for GCodeProcessor, so it can supress the commands when needed
         return gcode;
     }
 

src/libslic3r/GCode.hpp

@@ -1004,6 +1004,7 @@ protected:
         size_t                                                  num_objects,
         size_t                                                  num_islands);
 
+    friend class OozePrevention;
     friend class Wipe;
     friend class WipeTowerIntegration;
     friend class PressureEqualizer;

src/libslic3r/GCode/ToolOrdering.cpp

@@ -1276,6 +1276,13 @@ void ToolOrdering::collect_extruder_statistics(bool prime_multi_material)
         sort_remove_duplicates(m_all_printing_extruders);
     }
 
+    m_last_layer_per_extruder.clear();
+    for (const LayerTools& lt : m_layer_tools) {
+        for (unsigned int ext : lt.extruders) {
+            m_last_layer_per_extruder[ext] = lt.print_z;
+        }
+    }
+
     if (prime_multi_material && ! m_all_printing_extruders.empty()) {
         // Reorder m_all_printing_extruders in the sequence they will be primed, the last one will be m_first_printing_extruder.
         // Then set m_first_printing_extruder to the 1st extruder primed.
@@ -3664,5 +3671,11 @@ int WipingExtrusions::get_support_interface_extruder_overrides(const PrintObject
     return -1;
 }
 
-
+bool ToolOrdering::is_last_extrusion_layer(coordf_t print_z, unsigned int extruder_id) const
+{
+    auto it = m_last_layer_per_extruder.find(extruder_id);
+    if (it == m_last_layer_per_extruder.end())
+        return true;
+    return print_z >= it->second - EPSILON;
+}
 } // namespace Slic3r

src/libslic3r/GCode/ToolOrdering.hpp

@@ -370,6 +370,7 @@ public:
                                                   std::vector<int> & initial_filaments);
 
     bool                has_non_support_filament(const PrintConfig &config);
+    bool                is_last_extrusion_layer(coordf_t print_z, unsigned int extruder_id) const;
 
 private:
     void				initialize_layers(std::vector<coordf_t> &zs);
@@ -413,6 +414,8 @@ private:
     // which keeps every legacy per-object code path bit-identical (loops over an empty map are
     // no-ops; downstream emission falls through to the per-object branch).
     std::map<unsigned int, std::map<LayerTools::MixedSubLayerGroup::VolumeKey, std::vector<size_t>>> m_gradient_volume_layers;
+    // Map: extruder_id -> print_z (z coordinate) of the last layer it is used on
+    std::map<unsigned int, coordf_t> m_last_layer_per_extruder;
     const PrintObject*         m_print_object_ptr = nullptr;
     Print*                     m_print;
     bool                       m_sorted = false;

src/slic3r/CMakeLists.txt

@@ -222,6 +222,7 @@ set(SLIC3R_GUI_SOURCES
     GUI/Gizmos/GLGizmoUtils.hpp
     GUI/GLCanvas3D.cpp
     GUI/GLCanvas3D.hpp
+    GUI/SequentialPrintClearance.hpp
     GUI/GLModel.cpp
     GUI/GLModel.hpp
     GUI/GLSelectionRectangle.cpp

src/slic3r/GUI/GLCanvas3D.cpp

@@ -65,6 +65,7 @@
 #include <string_view>
 #include "slic3r/GUI/Selection.hpp"
 #include "GLCanvas3D.hpp"
+#include "SequentialPrintClearance.hpp"
 #ifdef SLIC3R_CAD
 #include "slic3r/GUI/CAD/DesignSketchTool.hpp"   // Design tab: interactive 2D sketch tool
 #endif
@@ -6397,17 +6398,16 @@ void GLCanvas3D::update_sequential_clearance()
     //BBS: add the height logic
     PartPlate* plate = wxGetApp().plater()->get_partplate_list().get_curr_plate();
     Polygons polygons;
-    std::vector<std::pair<Polygon, float>> height_polygons;
     polygons.reserve(instances_count);
-    height_polygons.reserve(instances_count);
-    std::vector<struct height_info> convex_and_bounding_boxes;
-    struct height_info
-    {
-        double         instance_height;
-        BoundingBox    bounding_box;
-        Polygon        hull_polygon;
-    };
+    std::vector<SequentialClearanceInstance> convex_and_bounding_boxes;
+    convex_and_bounding_boxes.reserve(instances_count);
+    std::map<ObjectID, int> print_order;
+    for (const PrintObject* print_object : fff_print()->objects())
+        for (const PrintInstance& instance : print_object->instances())
+            print_order.emplace(instance.model_instance->id(), instance.model_instance->arrange_order);
+
     for (size_t i = 0; i < instance_transforms.size(); ++i) {
+        const size_t first_instance = convex_and_bounding_boxes.size();
         const auto& instances = instance_transforms[i];
         double rotation_z0 = instances.front()->get_rotation().z();
         int index = 0;
@@ -6427,96 +6427,20 @@ void GLCanvas3D::update_sequential_clearance()
             Polygon convex_hull(std::move(inst_pts));
             BoundingBox bouding_box = convex_hull.bounding_box();
             BoundingBox plate_bb = plate->get_bounding_box_crd();
+            const ObjectID instance_id = m_model->objects[i]->instances[index]->id();
             double instance_height = m_model->objects[i]->get_instance_max_z(index++);
             //skip the object for not current plate
             if (!plate_bb.overlap(bouding_box))
                 continue;
-            convex_and_bounding_boxes.push_back({instance_height, bouding_box, convex_hull});
+            convex_and_bounding_boxes.push_back({instance_height, bouding_box, convex_hull, instance_id});
             polygons.emplace_back(std::move(convex_hull));
         }
+        sort_sequential_clearance_instances(convex_and_bounding_boxes.begin() + first_instance, convex_and_bounding_boxes.end(), print_order);
     }
 
-    //sort the print instance
-    std::sort(convex_and_bounding_boxes.begin(), convex_and_bounding_boxes.end(),
-        [](auto &l, auto &r) {
-            auto ly1 = l.bounding_box.min.y();
-            auto ly2 = l.bounding_box.max.y();
-            auto ry1 = r.bounding_box.min.y();
-            auto ry2 = r.bounding_box.max.y();
-            auto inter_min = std::max(ly1, ry1);
-            auto inter_max = std::min(ly2, ry2);
-            auto lx = l.bounding_box.min.x();
-            auto rx = r.bounding_box.min.x();
-            if (inter_max - inter_min > 0)
-                return (lx < rx) || ((lx == rx)&&(ly1 < ry1));
-            else
-                return (ly1 < ry1);
-        });
-
-    /*bool has_interlaced_objects = false;
-    for (int k = 0; k < bounding_box_count; k++)
-    {
-        Polygon& convex = convex_and_bounding_boxes[k].hull_polygon;
-        BoundingBox& bbox = convex_and_bounding_boxes[k].bounding_box;
-        auto iy1 = bbox.min.y();
-        auto iy2 = bbox.max.y();
-
-        for (int i = k+1; i < bounding_box_count; i++)
-        {
-            Polygon&     next_convex = convex_and_bounding_boxes[i].hull_polygon;
-            BoundingBox& next_bbox   = convex_and_bounding_boxes[i].bounding_box;
-            auto py1 = next_bbox.min.y();
-            auto py2 = next_bbox.max.y();
-            auto inter_min = std::max(iy1, py1); // min y of intersection
-            auto inter_max = std::min(iy2, py2); // max y of intersection. length=max_y-min_y>0 means intersection exists
-            if (inter_max - inter_min > 0) {
-                has_interlaced_objects = true;
-                break;
-            }
-        }
-        if (has_interlaced_objects)
-            break;
-    }*/
-
-    int bounding_box_count = convex_and_bounding_boxes.size();
-    double printable_height = fff_print()->config().printable_height;
-    double hc1 = fff_print()->config().extruder_clearance_height_to_lid;
-    double hc2 = fff_print()->config().extruder_clearance_height_to_rod;
-    for (int k = 0; k < bounding_box_count; k++)
-    {
-        Polygon& convex = convex_and_bounding_boxes[k].hull_polygon;
-        BoundingBox& bbox = convex_and_bounding_boxes[k].bounding_box;
-        auto iy1 = bbox.min.y();
-        auto iy2 = bbox.max.y();
-        double height = (k == (bounding_box_count - 1))?printable_height:hc1;
-
-        /*if (has_interlaced_objects) {
-            if ((k < (bounding_box_count - 1)) && (convex_and_bounding_boxes[k].instance_height > hc2)) {
-                height_polygons.emplace_back(std::make_pair(convex, hc2));
-            }
-        }
-        else {
-            if ((k < (bounding_box_count - 1)) && (convex_and_bounding_boxes[k].instance_height > hc1)) {
-                height_polygons.emplace_back(std::make_pair(convex, hc1));
-            }
-        }*/
-
-        for (int i = k+1; i < bounding_box_count; i++)
-        {
-            Polygon&     next_convex = convex_and_bounding_boxes[i].hull_polygon;
-            BoundingBox& next_bbox   = convex_and_bounding_boxes[i].bounding_box;
-            auto py1 = next_bbox.min.y();
-            auto py2 = next_bbox.max.y();
-            auto inter_min = std::max(iy1, py1); // min y of intersection
-            auto inter_max = std::min(iy2, py2); // max y of intersection. length=max_y-min_y>0 means intersection exists
-            if (inter_max - inter_min > 0) {
-                height = hc2;
-                break;
-            }
-        }
-        if (height < convex_and_bounding_boxes[k].instance_height)
-            height_polygons.emplace_back(std::make_pair(convex, height));
-    }
+    const auto& config = fff_print()->config();
+    const auto height_polygons = sequential_clearance_height_polygons(convex_and_bounding_boxes, config.printable_height,
+        config.extruder_clearance_height_to_lid, config.extruder_clearance_height_to_rod);
 
     // sends instances 2d hulls to be rendered
     set_sequential_print_clearance_visible(true);

src/slic3r/GUI/SequentialPrintClearance.hpp

@@ -0,0 +1,63 @@
+#pragma once
+
+#include "libslic3r/BoundingBox.hpp"
+#include "libslic3r/ObjectID.hpp"
+#include "libslic3r/Polygon.hpp"
+
+#include <algorithm>
+#include <cstddef>
+#include <map>
+#include <utility>
+#include <vector>
+
+namespace Slic3r::GUI {
+
+struct SequentialClearanceInstance
+{
+    double      instance_height;
+    BoundingBox bounding_box;
+    Polygon     hull_polygon;
+    ObjectID    instance_id;
+};
+
+// PrintApply may group rotated copies in a different order from ModelObject::instances.
+// Reorder one object's instances only when validation has assigned all of them an order.
+inline void sort_sequential_clearance_instances(
+    std::vector<SequentialClearanceInstance>::iterator first, std::vector<SequentialClearanceInstance>::iterator last,
+    const std::map<ObjectID, int>& print_order)
+{
+    if (!std::all_of(first, last, [&print_order](const SequentialClearanceInstance& instance) {
+            const auto order = print_order.find(instance.instance_id);
+            return order != print_order.end() && order->second > 0;
+        }))
+        return;
+
+    std::stable_sort(first, last, [&print_order](const SequentialClearanceInstance& lhs, const SequentialClearanceInstance& rhs) {
+        return print_order.at(lhs.instance_id) < print_order.at(rhs.instance_id);
+    });
+}
+
+// Input follows object-list order with validated print order within each object.
+inline std::vector<std::pair<Polygon, float>> sequential_clearance_height_polygons(
+    const std::vector<SequentialClearanceInstance>& instances, double printable_height, double height_to_lid, double height_to_rod)
+{
+    std::vector<std::pair<Polygon, float>> height_polygons;
+    height_polygons.reserve(instances.size());
+    for (size_t k = 0; k < instances.size(); ++k) {
+        const auto& instance = instances[k];
+        double height = k + 1 == instances.size() ? printable_height : height_to_lid;
+        for (size_t i = k + 1; i < instances.size(); ++i) {
+            const auto& next_bbox = instances[i].bounding_box;
+            if (std::min(instance.bounding_box.max.y(), next_bbox.max.y()) >
+                std::max(instance.bounding_box.min.y(), next_bbox.min.y())) {
+                height = height_to_rod;
+                break;
+            }
+        }
+        if (height < instance.instance_height)
+            height_polygons.emplace_back(instance.hull_polygon, float(height));
+    }
+    return height_polygons;
+}
+
+} // namespace Slic3r::GUI

tests/data/wipe_tower_temperature_trace_main.txt

@@ -163,7 +163,7 @@ M109 S240 T0 ; set nozzle temperature and wait for it to be reached
 ; CP TOOLCHANGE END
 M104 S240 T1 ; preheat T1 time: 30s	lead 30.0s
 ; CP TOOLCHANGE START
-M104 S200 T0 ; set nozzle temperature ;cooldown
+M104 S0 T0 ; set nozzle temperature ;cooldown
 T1 ; change extruder
 M109 S240 T1 ; set nozzle temperature and wait for it to be reached
 ; CP TOOLCHANGE END

tests/fff_print/test_multifilament.cpp

@@ -1742,3 +1742,112 @@ TEST_CASE("Each filament cools with the fan speeds of its extruder variant", "[M
         CHECK(gcode.find("; start range high " + std::to_string(range_high) + "\n") != std::string::npos);
     }
 }
+
+TEST_CASE("Shared heater on IMEX printer stays hot until all filaments on it are done", "[MultiFilament]")
+{
+    DynamicPrintConfig cfg = multifilament_config(7);
+    cfg.set_deserialize_strict({
+        {"ooze_prevention", 1},
+        {"preheat_time", 0},
+        {"single_extruder_multi_material", 0},
+    });
+    imex_7x4_printer(cfg);
+
+    const std::string gcode = slice_with_object_overrides({make_cube(20., 20., 10.), make_cube(20., 20., 4.), make_cube(20., 20., 10.)},
+                                                          cfg,
+                                                          {{{"extruder", 1}, {"layer_height", 0.30}},
+                                                           {{"extruder", 2}, {"layer_height", 0.15}},
+                                                           {{"extruder", 5}}});
+
+    bool premature_s0_t0 = false;
+    double current_z     = 0.0;
+
+    GCodeReader reader;
+    reader.parse_buffer(gcode, [&](GCodeReader& /*self*/, const GCodeReader::GCodeLine& line) {
+        if (line.has_z())
+            current_z = line.z();
+
+        const std::string raw = line.raw();
+        if (raw.find("M104 S0 T0") != std::string::npos && raw.find(";cooldown") != std::string::npos) {
+            if (current_z < 9.0)
+                premature_s0_t0 = true;
+        }
+    });
+
+    // Filaments 1 and 2 share head 0, and filament 1 prints up to 10mm.
+    // T0 must not shut down at ~4mm when filament 2 finishes.
+    CHECK_FALSE(premature_s0_t0);
+}
+
+TEST_CASE("Unused extruder turns off after its final layer on multi-object print", "[MultiFilament]")
+{
+    const std::string gcode = slice_with_object_overrides(
+        { make_cube(20., 20., 10.), make_cube(20., 20., 4.) },
+        multifilament_config(2, {
+            { "single_extruder_multi_material", 0 },
+            { "ooze_prevention",                1 },
+            { "standby_temperature_delta",      -40 },
+            { "nozzle_temperature",             "240,240" },
+        }),
+        {
+            { { "extruder", 1 }, { "layer_height", 0.20 } },
+            { { "extruder", 2 }, { "layer_height", 0.15 } }
+        });
+
+    int t1_s0_cooldown_count = 0;
+    int t0_s0_cooldown_count = 0;
+
+    std::istringstream stream(gcode);
+    for (std::string line; std::getline(stream, line);) {
+        if (line.find(";cooldown") != std::string::npos) {
+            if (line.find("M104 S0 T1") != std::string::npos)
+                ++t1_s0_cooldown_count;
+            if (line.find("M104 S0 T0") != std::string::npos)
+                ++t0_s0_cooldown_count;
+        }
+    }
+
+    // T1 (extruder 2, 4mm cube) gets exactly one S0 after its last layer.
+    // T0 (extruder 1, 10mm cube) never gets S0 mid-print.
+    CHECK(t1_s0_cooldown_count == 1);
+    CHECK(t0_s0_cooldown_count == 0);
+}
+
+TEST_CASE("Unused extruder turns off on non-IMEX three-tool print", "[MultiFilament]")
+{
+    const std::string gcode = slice_with_object_overrides(
+        { make_cube(20., 20., 4.), make_cube(20., 20., 10.), make_cube(20., 20., 10.) },
+        multifilament_config(3, {
+            { "single_extruder_multi_material", 0 },
+            { "ooze_prevention",                1 },
+            { "standby_temperature_delta",      -40 },
+            { "nozzle_temperature",             "240,240,240" },
+        }),
+        {
+            { { "extruder", 1 } },
+            { { "extruder", 2 } },
+            { { "extruder", 3 } }
+        });
+
+    bool premature_s0_t1 = false;
+    bool premature_s0_t2 = false;
+    double current_z     = 0.0;
+
+    GCodeReader reader;
+    reader.parse_buffer(gcode, [&](GCodeReader& /*self*/, const GCodeReader::GCodeLine& line) {
+        if (line.has_z())
+            current_z = line.z();
+
+        const std::string raw = line.raw();
+        if (raw.find(";cooldown") != std::string::npos && current_z < 9.0) {
+            if (raw.find("M104 S0 T1") != std::string::npos)
+                premature_s0_t1 = true;
+            if (raw.find("M104 S0 T2") != std::string::npos)
+                premature_s0_t2 = true;
+        }
+    });
+
+    // T1 and T2 print up to 10mm — neither should get S0 before that.
+    CHECK_FALSE(premature_s0_t1);
+    CHECK_FALSE(premature_s0_t2);
+}

tests/slic3rutils/CMakeLists.txt

@@ -47,6 +47,7 @@ add_executable(${_TEST_NAME}_tests
     test_file_url.cpp
     test_imgui_wrapper.cpp
     test_user_manager.cpp
+    test_sequential_clearance.cpp
     ../fff_print/test_helpers.cpp
     )
 

tests/slic3rutils/test_sequential_clearance.cpp

@@ -0,0 +1,162 @@
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/generators/catch_generators.hpp>
+#include <catch2/matchers/catch_matchers_floating_point.hpp>
+
+#include "catch2/matchers/catch_matchers.hpp"
+#include "fff_print/test_helpers.hpp"
+#include "slic3r/GUI/SequentialPrintClearance.hpp"
+
+#include <libslic3r/libslic3r.h>
+#include <libslic3r/Model.hpp>
+#include <libslic3r/TriangleMesh.hpp>
+#include <libslic3r/PrintConfig.hpp>
+#include <libslic3r/Print.hpp>
+#include <libslic3r/Polygon.hpp>
+#include <libslic3r/ObjectID.hpp>
+#include <cstddef>
+#include <map>
+#include <vector>
+#include <utility>
+
+using namespace Slic3r;
+using namespace Slic3r::GUI;
+using Catch::Matchers::WithinAbs;
+
+namespace {
+
+SequentialClearanceInstance instance(coord_t x, coord_t y, double height)
+{
+    return {height, BoundingBox(Point(x, y), Point(x + 5, y + 10)),
+        Polygon{Point(x, y), Point(x + 5, y), Point(x + 5, y + 10), Point(x, y + 10)}};
+}
+
+} // namespace
+
+TEST_CASE("Sequential clearance preserves model print order when objects move", "[SequentialClearance][Regression]")
+{
+    const coord_t last_y = GENERATE(-20, 20);
+    std::vector<SequentialClearanceInstance> instances{instance(20, 0, 50.), instance(0, last_y, 50.)};
+    const auto warnings = sequential_clearance_height_polygons(instances, 200., 30., 10.);
+
+    REQUIRE(warnings.size() == 1);
+    CHECK(warnings.front().first == instance(20, 0, 50.).hull_polygon);
+    CHECK_THAT(warnings.front().second, WithinAbs(30., 1e-6));
+}
+
+TEST_CASE("Sequential clearance handles chains of overlapping Y ranges", "[SequentialClearance][Regression]")
+{
+    // A overlaps B, B overlaps C, but A does not overlap C. Combining X order
+    // for overlaps with Y order otherwise formed the cycle B < A < C < B.
+    std::vector<SequentialClearanceInstance> instances{
+        instance(20, 0, 50.), instance(10, 8, 50.), instance(0, 16, 50.)};
+    const auto warnings = sequential_clearance_height_polygons(instances, 200., 30., 10.);
+
+    REQUIRE(warnings.size() == 2);
+    CHECK(warnings[0].first == instance(20, 0, 50.).hull_polygon);
+    CHECK(warnings[1].first == instance(10, 8, 50.).hull_polygon);
+    CHECK_THAT(warnings[0].second, WithinAbs(10., 1e-6));
+    CHECK_THAT(warnings[1].second, WithinAbs(10., 1e-6));
+}
+
+TEST_CASE("Sequential clearance applies rod height only to positive Y overlap", "[SequentialClearance]")
+{
+    const coord_t next_y = GENERATE(9, 10, 11);
+    std::vector<SequentialClearanceInstance> instances{instance(0, 0, 50.), instance(20, next_y, 50.)};
+    const auto warnings = sequential_clearance_height_polygons(instances, 200., 30., 10.);
+
+    REQUIRE(warnings.size() == 1);
+    CHECK(warnings.front().first == instances.front().hull_polygon);
+    CHECK_THAT(warnings.front().second, WithinAbs(next_y < 10 ? 10. : 30., 1e-6));
+}
+
+TEST_CASE("Sequential clearance allows the last object up to printable height", "[SequentialClearance]")
+{
+    std::vector<SequentialClearanceInstance> instances;
+    CHECK(sequential_clearance_height_polygons(instances, 200., 30., 10.).empty());
+
+    instances.push_back(instance(0, 0, 200.));
+    CHECK(sequential_clearance_height_polygons(instances, 200., 30., 10.).empty());
+
+    instances.front().instance_height = 201.;
+    const auto warnings = sequential_clearance_height_polygons(instances, 200., 30., 10.);
+    REQUIRE(warnings.size() == 1);
+    CHECK_THAT(warnings.front().second, WithinAbs(200., 1e-6));
+}
+
+TEST_CASE("Sequential clearance warns the same rotated copy as print validation", "[SequentialClearance][Regression]")
+{
+    constexpr double rod_height = 10.;
+    constexpr double lid_height = 30.;
+    constexpr double printable_height = 200.;
+    Model model = Test::model("rotated copies", make_cube(10., 10., 50.));
+    ModelObject* object = model.objects.front();
+    object->instances.front()->set_offset(Vec3d(150., 80., 0.));
+    ModelInstance* rotated = object->add_instance();
+    rotated->set_offset(Vec3d(50., 80., 0.));
+    rotated->set_rotation(Z, PI / 2.);
+
+    DynamicPrintConfig config = DynamicPrintConfig::full_print_config();
+    config.set_deserialize_strict({{"print_sequence", "by object"}, {"extruder_clearance_radius", 20.},
+        {"extruder_clearance_height_to_lid", lid_height}, {"extruder_clearance_height_to_rod", rod_height},
+        {"printable_height", printable_height}});
+    Print print;
+    print.auto_assign_extruders(object);
+    print.apply(model, config);
+    Polygons polygons;
+    std::vector<std::pair<Polygon, float>> validation_warnings;
+    Print::sequential_print_clearance_valid(print, &polygons, &validation_warnings);
+
+    std::map<ObjectID, int> print_order;
+    for (const PrintObject* print_object : print.objects())
+        for (const PrintInstance& print_instance : print_object->instances())
+            print_order.emplace(print_instance.model_instance->id(), print_instance.model_instance->arrange_order);
+
+    std::vector<SequentialClearanceInstance> instances;
+    for (size_t i = 0; i < object->instances.size(); ++i) {
+        Polygon hull = object->convex_hull_2d(object->instances[i]->get_matrix());
+        instances.push_back({object->get_instance_max_z(i), hull.bounding_box(), hull, object->instances[i]->id()});
+    }
+    const Polygon expected_warning = instances[1].hull_polygon;
+    REQUIRE(validation_warnings.size() == 1);
+    CHECK(validation_warnings.front().first.bounding_box().contains(instances[1].bounding_box.center()));
+    CHECK_FALSE(validation_warnings.front().first.bounding_box().contains(instances[0].bounding_box.center()));
+
+    sort_sequential_clearance_instances(instances.begin(), instances.end(), print_order);
+    const auto warnings = sequential_clearance_height_polygons(instances, printable_height, lid_height, rod_height);
+    REQUIRE(warnings.size() == 1);
+    CHECK(warnings.front().first == expected_warning);
+    CHECK_THAT(warnings.front().second, WithinAbs(rod_height, 1e-6));
+}
+
+TEST_CASE("Sequential clearance keeps copy order when print order is unavailable", "[SequentialClearance]")
+{
+    std::vector<SequentialClearanceInstance> instances{instance(20, 0, 50.), instance(0, 0, 50.)};
+    instances[0].instance_id = ObjectID(1);
+    instances[1].instance_id = ObjectID(2);
+    std::map<ObjectID, int> print_order{{ObjectID(1), 2}, {ObjectID(2), 1}};
+
+    SECTION("No validation order") { print_order.clear(); }
+    SECTION("New copy missing from print") { print_order.erase(ObjectID(2)); }
+    SECTION("Copy has not been ordered") { print_order[ObjectID(2)] = 0; }
+    SECTION("Copy has an invalid order") { print_order[ObjectID(2)] = -1; }
+
+    sort_sequential_clearance_instances(instances.begin(), instances.end(), print_order);
+    CHECK(instances[0].instance_id == ObjectID(1));
+    CHECK(instances[1].instance_id == ObjectID(2));
+}
+
+TEST_CASE("Sequential clearance keeps object order when sorting copies", "[SequentialClearance]")
+{
+    std::vector<SequentialClearanceInstance> instances(4, instance(0, 0, 50.));
+    for (size_t i = 0; i < instances.size(); ++i)
+        instances[i].instance_id = ObjectID(instances.size() - i);
+    const std::map<ObjectID, int> print_order{{ObjectID(1), 1}, {ObjectID(2), 2}, {ObjectID(3), 3}, {ObjectID(4), 4}};
+
+    // The two objects were reordered in the model since the last validation.
+    sort_sequential_clearance_instances(instances.begin(), instances.begin() + 2, print_order);
+    sort_sequential_clearance_instances(instances.begin() + 2, instances.end(), print_order);
+    CHECK(instances[0].instance_id == ObjectID(3));
+    CHECK(instances[1].instance_id == ObjectID(4));
+    CHECK(instances[2].instance_id == ObjectID(1));
+    CHECK(instances[3].instance_id == ObjectID(2));
+}