Keep the Design tab's bed, grid and reference planes aligned on every plate

docs/HLSD/design-tab.md

@@ -246,6 +246,15 @@ The tab is a page of Orca's main window and answers to the same settings as Prep
   `DesignRowList` rather than a `wxTreeCtrl`, so each row carries its own actions — Edit,
   Show/hide and Delete on a feature, Move, Show/hide and Delete on a body — and the eye shows
   whether that row is hidden.
+- **Plates.** This is the one thing the tab does not follow. The canvas has a bed of its own at
+  the printer bed's home position, whichever plate Prepare has current, and a new document's
+  modeling origin is that bed's centre. A bed that followed the current plate would slide out
+  from under a design: the origin is fixed once per document, baked into every sketch plane and
+  saved in the recipe, while the current plate can change between visits. Commit to Plate does
+  not need it either, since the committed object is placed on an empty spot of the current
+  plate. What the canvas does read from the plate is moved onto its bed: the exclude areas, the
+  plate box the camera orbits about when nothing is picked (`GLCanvas3D::_current_plate_box`),
+  and the first view, which starts as a copy of Prepare's camera.
 - **Viewport text.** The status line and the active tool's values are drawn by the canvas in
   its ImGui pass, so they go with the canvas: a top-level window over GL does not follow its
   frame and was left floating over other applications.

src/slic3r/GUI/CAD/DesignCanvas.cpp

@@ -8,6 +8,7 @@
 #include "slic3r/GUI/Camera.hpp"   // N: look down the sketch plane normal
 #include "slic3r/GUI/GUI_App.hpp"
 #include "slic3r/GUI/Plater.hpp"
+#include "slic3r/GUI/PartPlate.hpp"   // the current plate's origin: the first view's offset
 #include "slic3r/GUI/ImGuiWrapper.hpp"
 #include "slic3r/GUI/GLToolbar.hpp"
 #include "slic3r/GUI/Event.hpp"
@@ -190,8 +191,11 @@ DesignCanvas::DesignCanvas(wxWindow* parent)
     refresh_bed();
 
     // The view this canvas opens on. Built lazily, on the way into the Design tab, so this
-    // is the view the user is looking at right now.
+    // is the view the user is looking at right now — moved off the current plate onto the
+    // Design bed, which stays at the printer bed's home whichever plate is current.
     m_parked_camera = wxGetApp().plater()->get_camera();
+    if (PartPlate* plate = wxGetApp().plater()->get_partplate_list().get_curr_plate())
+        m_parked_camera.translate_world(-plate->get_origin());
 
     // Before any of this class's own Binds below: wx calls dynamically bound handlers in
     // reverse order of binding, and GLCanvas3D swallows several events without skipping them —
@@ -554,6 +558,7 @@ void DesignCanvas::refresh_bed()
     double printable_height = 100.0;
     const auto* ph_opt = config->opt<ConfigOptionFloat>("printable_height");
     if (ph_opt) printable_height = ph_opt->value;
+    // No position: the Design bed stays at the printer bed's home, whichever plate is current.
     m_bed.set_shape(bed_shape_opt->values, printable_height, {}, {}, "", false);  // mainline added extruder_areas/heights params
 }
 

src/slic3r/GUI/CAD/DesignCanvas.hpp

@@ -3,6 +3,7 @@
 
 #include <vector>
 #include "libslic3r/Point.hpp"
+#include "libslic3r/BuildVolume.hpp"
 #include "libslic3r/Color.hpp"
 #include <utility>
 #include <wx/colour.h>
@@ -83,6 +84,8 @@ public:
     void finish_sketch();
     bool is_sketching() const;
     void refresh_bed();   // re-sync the bed to the current printer (call on tab activation)
+    // Centre of the Design bed: the printer bed at its home position, whichever plate is current.
+    Vec2d bed_center() const { return m_bed.build_volume().bed_center(); }
     // The Camera is Plater-owned and shared with Prepare/Preview/Assemble; GLCanvas3D has no
     // per-canvas camera, so every orbit here would otherwise overwrite what the editor tabs
     // show. Exactly one of the two views is live at a time, so entering and leaving are the

src/slic3r/GUI/CAD/DesignPanel.cpp

@@ -104,7 +104,6 @@
 #include "libslic3r/Model.hpp"
 #include "slic3r/GUI/GUI_App.hpp"
 #include "slic3r/GUI/Plater.hpp"
-#include "libslic3r/BuildVolume.hpp"
 #include "slic3r/GUI/MainFrame.hpp"
 #include "slic3r/GUI/GUI_ObjectList.hpp"
 #include "slic3r/GUI/Shortcuts.hpp"
@@ -7345,8 +7344,12 @@ void DesignPanel::hydrate_from_model()
     // that has none yet. A design in progress keeps its origin: its sketches have it baked into
     // their planes, so moving it under them (a printer change between visits) would slide the
     // datum planes off the geometry. A loaded project brings its own (load_recipe).
+    // The centre of the Design bed, not the plater's: the plater moves its bed onto the current
+    // plate, so on plate 2+ the origin would land one plate stride away from the bed drawn here.
+    // Re-synced first because the control socket calls this without on_tab_shown().
     if (!m_doc.origin_from_recipe) {
-        const Vec2d bc = plater->build_volume().bed_center();
+        m_viewport->refresh_bed();
+        const Vec2d bc = m_viewport->bed_center();
         m_doc.modeling_origin = Vec3d(bc.x(), bc.y(), 0.0);
         // A document started here takes the weld rule from the preference; a loaded one
         // brings its own (load_recipe).

src/slic3r/GUI/GLCanvas3D.cpp

@@ -1875,7 +1875,7 @@ BoundingBoxf3 GLCanvas3D::volumes_bounding_box(bool current_plate_only) const
     bool          is_limit = m_canvas_type != ECanvasType::CanvasAssembleView;
     if (is_limit) {
         if (current_plate_only) {
-            expand_part_plate_list_box = wxGetApp().plater()->get_partplate_list().get_curr_plate()->get_bounding_box();
+            expand_part_plate_list_box = _current_plate_box();
         } else {
             auto        plate_list_box = wxGetApp().plater()->get_partplate_list().get_bounding_box();
             auto        horizontal_radius = 0.5 * sqrt(std::pow(plate_list_box.min[0] - plate_list_box.max[0], 2) + std::pow(plate_list_box.min[1] - plate_list_box.max[1], 2));
@@ -8267,7 +8267,30 @@ void GLCanvas3D::_render_bed(const Transform3d& view_matrix, const Transform3d&
 
 void GLCanvas3D::_render_platelist(const Transform3d& view_matrix, const Transform3d& projection_matrix, bool bottom, bool only_current, bool only_body, int hover_id, bool render_cali, bool show_grid)
 {
-    wxGetApp().plater()->get_partplate_list().render(view_matrix, projection_matrix, bottom, only_current, only_body, hover_id, render_cali, show_grid, !m_plate_chrome_enabled);
+    PartPlateList& plate_list = wxGetApp().plater()->get_partplate_list();
+    // Design tab: its bed stays at the printer bed's home whichever plate is current, so the
+    // current plate's exclude areas are moved from that plate onto it.
+    PartPlate* curr_plate = plate_list.get_curr_plate();
+    const Transform3d plate_view_matrix = m_axes_at_bed_center && curr_plate != nullptr ?
+        Transform3d(view_matrix * Geometry::translation_transform(-curr_plate->get_origin())) : view_matrix;
+    plate_list.render(plate_view_matrix, projection_matrix, bottom, only_current, only_body, hover_id, render_cali, show_grid, !m_plate_chrome_enabled);
+}
+
+BoundingBoxf3 GLCanvas3D::_current_plate_box() const
+{
+    // Design tab: its own bed stands in for the current plate (see _render_platelist).
+    const BuildVolume& build_volume = m_bed.build_volume();
+    if (m_axes_at_bed_center && build_volume.valid()) {
+        // Flat at z = 0 like the plate's own box. Merged, as PartPlate builds it: the min/max
+        // constructor leaves a flat box undefined.
+        const BoundingBoxf bb = build_volume.bounding_volume2d();
+        BoundingBoxf3      box;
+        box.merge(Vec3d(bb.min.x(), bb.min.y(), 0.));
+        box.merge(Vec3d(bb.max.x(), bb.max.y(), 0.));
+        return box;
+    }
+    PartPlate* curr_plate = wxGetApp().plater()->get_partplate_list().get_curr_plate();
+    return curr_plate != nullptr ? curr_plate->get_bounding_box() : BoundingBoxf3();
 }
 
 // Design tab: CAD grid on the bed plane, drawn in place of the plate's corner-origin grid.
@@ -11061,10 +11084,9 @@ std::optional<Vec3d> GLCanvas3D::get_camera_orbit_target(ECameraNavigationType n
 {
     // Orca: Centralize the pre-existing pivot rules so orbiting and pan fallback cannot
     // choose different reference depths for the same canvas and active tool.
-    PartPlate* current_plate = wxGetApp().plater()->get_partplate_list().get_curr_plate();
+    const BoundingBoxf3 plate_box = _current_plate_box();
     if (navigation_type == ECameraNavigationType::Gesture)
-        return current_plate == nullptr ? std::nullopt :
-            std::make_optional(current_plate->get_bounding_box().center());
+        return plate_box.defined ? std::make_optional(plate_box.center()) : std::nullopt;
 
     const GLGizmosManager::EType gizmo_type = m_gizmos.get_current_type();
     const bool use_scene_target = m_canvas_type == ECanvasType::CanvasAssembleView ||
@@ -11084,15 +11106,15 @@ std::optional<Vec3d> GLCanvas3D::get_camera_orbit_target(ECameraNavigationType n
 
     Vec3d target = Vec3d::Zero();
     if (m_canvas_type == ECanvasType::CanvasPreview) {
-        if (current_plate != nullptr)
-            target = current_plate->get_bounding_box().center();
+        if (plate_box.defined)
+            target = plate_box.center();
     } else if (!m_selection.is_empty()) {
         target = m_selection.get_bounding_box().center();
     } else {
         // Orca: Match regular mouse orbit: objects on the active plate, then the plate itself.
         BoundingBoxf3 bbox = volumes_bounding_box(true);
-        if (!bbox.defined && current_plate != nullptr)
-            bbox = current_plate->get_bounding_box();
+        if (!bbox.defined)
+            bbox = plate_box;
         if (bbox.defined)
             target = bbox.center();
     }

src/slic3r/GUI/GLCanvas3D.hpp

@@ -1441,6 +1441,8 @@ private:
     void _render_shadows(const Transform3d& view_matrix, const Transform3d& projection_matrix);
     //BBS: add part plate related logic
     void _render_platelist(const Transform3d& view_matrix, const Transform3d& projection_matrix, bool bottom, bool only_current, bool only_body = false, int hover_id = -1, bool render_cali = false, bool show_grid = true);
+    // The current plate's box (XY, at z = 0); in the Design tab, its own bed's.
+    BoundingBoxf3 _current_plate_box() const;
     // Design tab: draw the CAD grid (minor 10 mm + major 50 mm) in place of the plate's
     // corner-origin grid when the axes sit at the bed centre (modeling origin). Rebuilds its
     // GLModels lazily, only when the bed shape changed.