Reworked handling of approximate / snug bounding boxes

at Model / ModelObject / PrintObject
Fixes #9467 #9519 #9646
Also fixed variable layer height editing for case such as mentioned
in the github issues above.
Also likely fixed some of the sinking objects issues.

src/PrusaSlicer.cpp

@@ -382,7 +382,7 @@ int CLI::run(int argc, char **argv)
         } else if (opt_key == "align_xy") {
             const Vec2d &p = m_config.option<ConfigOptionPoint>("align_xy")->value;
             for (auto &model : m_models) {
-                BoundingBoxf3 bb = model.bounding_box();
+                BoundingBoxf3 bb = model.bounding_box_exact();
                 // this affects volumes:
                 model.translate(-(bb.min.x() - p.x()), -(bb.min.y() - p.y()), -bb.min.z());
             }
@@ -423,7 +423,7 @@ int CLI::run(int argc, char **argv)
         } else if (opt_key == "cut" || opt_key == "cut_x" || opt_key == "cut_y") {
             std::vector<Model> new_models;
             for (auto &model : m_models) {
-                model.translate(0, 0, -model.bounding_box().min.z());  // align to z = 0
+                model.translate(0, 0, -model.bounding_box_exact().min.z());  // align to z = 0
                 size_t num_objects = model.objects.size();
                 for (size_t i = 0; i < num_objects; ++ i) {
 

src/libslic3r/Model.cpp

@@ -323,14 +323,30 @@ bool Model::add_default_instances()
 }
 
 // this returns the bounding box of the *transformed* instances
-BoundingBoxf3 Model::bounding_box() const
+BoundingBoxf3 Model::bounding_box_approx() const
 {
     BoundingBoxf3 bb;
     for (ModelObject *o : this->objects)
-        bb.merge(o->bounding_box());
+        bb.merge(o->bounding_box_approx());
     return bb;
 }
 
+BoundingBoxf3 Model::bounding_box_exact() const
+{
+    BoundingBoxf3 bb;
+    for (ModelObject *o : this->objects)
+        bb.merge(o->bounding_box_exact());
+    return bb;
+}
+
+double Model::max_z() const
+{
+    double z = 0;
+    for (ModelObject *o : this->objects)
+        z = std::max(z, o->max_z());
+    return z;
+}
+
 unsigned int Model::update_print_volume_state(const BuildVolume &build_volume)
 {
     unsigned int num_printable = 0;
@@ -377,7 +393,7 @@ void Model::duplicate_objects_grid(size_t x, size_t y, coordf_t dist)
     ModelObject* object = this->objects.front();
     object->clear_instances();
 
-    Vec3d ext_size = object->bounding_box().size() + dist * Vec3d::Ones();
+    Vec3d ext_size = object->bounding_box_exact().size() + dist * Vec3d::Ones();
 
     for (size_t x_copy = 1; x_copy <= x; ++x_copy) {
         for (size_t y_copy = 1; y_copy <= y; ++y_copy) {
@@ -548,13 +564,13 @@ void Model::adjust_min_z()
     if (objects.empty())
         return;
 
-    if (bounding_box().min(2) < 0.0)
+    if (this->bounding_box_exact().min.z() < 0.0)
     {
         for (ModelObject* obj : objects)
         {
             if (obj != nullptr)
             {
-                coordf_t obj_min_z = obj->bounding_box().min(2);
+                coordf_t obj_min_z = obj->min_z();
                 if (obj_min_z < 0.0)
                     obj->translate_instances(Vec3d(0.0, 0.0, -obj_min_z));
             }
@@ -627,8 +643,11 @@ ModelObject& ModelObject::assign_copy(const ModelObject &rhs)
     this->printable                   = rhs.printable;
     this->origin_translation          = rhs.origin_translation;
     this->cut_id.copy(rhs.cut_id);
-    m_bounding_box                    = rhs.m_bounding_box;
+    m_bounding_box_approx             = rhs.m_bounding_box_approx;
-    m_bounding_box_valid              = rhs.m_bounding_box_valid;
+    m_bounding_box_approx_valid       = rhs.m_bounding_box_approx_valid;
+    m_bounding_box_exact              = rhs.m_bounding_box_exact;
+    m_bounding_box_exact_valid        = rhs.m_bounding_box_exact_valid;
+    m_min_max_z_valid                 = rhs.m_min_max_z_valid;
     m_raw_bounding_box                = rhs.m_raw_bounding_box;
     m_raw_bounding_box_valid          = rhs.m_raw_bounding_box_valid;
     m_raw_mesh_bounding_box           = rhs.m_raw_mesh_bounding_box;
@@ -668,8 +687,11 @@ ModelObject& ModelObject::assign_copy(ModelObject &&rhs)
     this->layer_height_profile        = std::move(rhs.layer_height_profile);
     this->printable                   = std::move(rhs.printable);
     this->origin_translation          = std::move(rhs.origin_translation);
-    m_bounding_box                    = std::move(rhs.m_bounding_box);
+    m_bounding_box_approx             = std::move(rhs.m_bounding_box_approx);
-    m_bounding_box_valid              = std::move(rhs.m_bounding_box_valid);
+    m_bounding_box_approx_valid       = std::move(rhs.m_bounding_box_approx_valid);
+    m_bounding_box_exact              = std::move(rhs.m_bounding_box_exact);
+    m_bounding_box_exact_valid        = std::move(rhs.m_bounding_box_exact_valid);
+    m_min_max_z_valid                 = rhs.m_min_max_z_valid;
     m_raw_bounding_box                = rhs.m_raw_bounding_box;
     m_raw_bounding_box_valid          = rhs.m_raw_bounding_box_valid;
     m_raw_mesh_bounding_box           = rhs.m_raw_mesh_bounding_box;
@@ -864,16 +886,73 @@ void ModelObject::clear_instances()
 
 // Returns the bounding box of the transformed instances.
 // This bounding box is approximate and not snug.
-const BoundingBoxf3& ModelObject::bounding_box() const
+const BoundingBoxf3& ModelObject::bounding_box_approx() const
 {
-    if (! m_bounding_box_valid) {
+    if (! m_bounding_box_approx_valid) {
-        m_bounding_box_valid = true;
+        m_bounding_box_approx_valid = true;
         BoundingBoxf3 raw_bbox = this->raw_mesh_bounding_box();
-        m_bounding_box.reset();
+        m_bounding_box_approx.reset();
         for (const ModelInstance *i : this->instances)
-            m_bounding_box.merge(i->transform_bounding_box(raw_bbox));
+            m_bounding_box_approx.merge(i->transform_bounding_box(raw_bbox));
+    }
+    return m_bounding_box_approx;
+}
+
+// Returns the bounding box of the transformed instances.
+// This bounding box is approximate and not snug.
+const BoundingBoxf3& ModelObject::bounding_box_exact() const
+{
+    if (! m_bounding_box_exact_valid) {
+        m_bounding_box_exact_valid = true;
+        m_min_max_z_valid = true;
+        BoundingBoxf3 raw_bbox = this->raw_mesh_bounding_box();
+        m_bounding_box_exact.reset();
+        for (size_t i = 0; i < this->instances.size(); ++ i)
+            m_bounding_box_exact.merge(this->instance_bounding_box(i));
+    }
+    return m_bounding_box_exact;
+}
+
+double ModelObject::min_z() const
+{
+    const_cast<ModelObject*>(this)->update_min_max_z();
+    return m_bounding_box_exact.min.z();
+}
+
+double ModelObject::max_z() const
+{
+    const_cast<ModelObject*>(this)->update_min_max_z();
+    return m_bounding_box_exact.max.z();
+}
+
+void ModelObject::update_min_max_z()
+{
+    assert(! this->instances.empty());
+    if (! m_min_max_z_valid && ! this->instances.empty()) {
+        m_min_max_z_valid = true;
+        const Transform3d mat_instance = this->instances.front()->get_transformation().get_matrix();
+        double global_min_z = std::numeric_limits<double>::max();
+        double global_max_z = - std::numeric_limits<double>::max();
+        for (const ModelVolume *v : this->volumes)
+            if (v->is_model_part()) {
+                const Transform3d m = mat_instance * v->get_matrix();
+                const Vec3d  row_z   = m.linear().row(2).cast<double>();
+                const double shift_z = m.translation().z();
+                double this_min_z = std::numeric_limits<double>::max();
+                double this_max_z = - std::numeric_limits<double>::max();
+                for (const Vec3f &p : v->mesh().its.vertices) {
+                    double z = row_z.dot(p.cast<double>());
+                    this_min_z = std::min(this_min_z, z);
+                    this_max_z = std::max(this_max_z, z);
+                }
+                this_min_z += shift_z;
+                this_max_z += shift_z;
+                global_min_z = std::min(global_min_z, this_min_z);
+                global_max_z = std::max(global_max_z, this_max_z);
+            }
+        m_bounding_box_exact.min.z() = global_min_z;
+        m_bounding_box_exact.max.z() = global_max_z;
     }
-    return m_bounding_box;
 }
 
 // A mesh containing all transformed instances of this object.
@@ -1031,19 +1110,19 @@ void ModelObject::ensure_on_bed(bool allow_negative_z)
 
     if (allow_negative_z) {
         if (parts_count() == 1) {
-            const double min_z = get_min_z();
+            const double min_z = this->min_z();
-            const double max_z = get_max_z();
+            const double max_z = this->max_z();
             if (min_z >= SINKING_Z_THRESHOLD || max_z < 0.0)
                 z_offset = -min_z;
         }
         else {
-            const double max_z = get_max_z();
+            const double max_z = this->max_z();
             if (max_z < SINKING_MIN_Z_THRESHOLD)
                 z_offset = SINKING_MIN_Z_THRESHOLD - max_z;
         }
     }
     else
-        z_offset = -get_min_z();
+        z_offset = -this->min_z();
 
     if (z_offset != 0.0)
         translate_instances(z_offset * Vec3d::UnitZ());
@@ -1070,8 +1149,10 @@ void ModelObject::translate(double x, double y, double z)
         v->translate(x, y, z);
     }
 
-    if (m_bounding_box_valid)
+    if (m_bounding_box_approx_valid)
-        m_bounding_box.translate(x, y, z);
+        m_bounding_box_approx.translate(x, y, z);
+    if (m_bounding_box_exact_valid)
+        m_bounding_box_exact.translate(x, y, z);
 }
 
 void ModelObject::scale(const Vec3d &versor)
@@ -1866,32 +1947,6 @@ void ModelObject::bake_xy_rotation_into_meshes(size_t instance_idx)
     this->invalidate_bounding_box();
 }
 
-double ModelObject::get_min_z() const
-{
-    if (instances.empty())
-        return 0.0;
-    else {
-        double min_z = DBL_MAX;
-        for (size_t i = 0; i < instances.size(); ++i) {
-            min_z = std::min(min_z, get_instance_min_z(i));
-        }
-        return min_z;
-    }
-}
-
-double ModelObject::get_max_z() const
-{
-    if (instances.empty())
-        return 0.0;
-    else {
-        double max_z = -DBL_MAX;
-        for (size_t i = 0; i < instances.size(); ++i) {
-            max_z = std::max(max_z, get_instance_max_z(i));
-        }
-        return max_z;
-    }
-}
-
 double ModelObject::get_instance_min_z(size_t instance_idx) const
 {
     double min_z = DBL_MAX;
@@ -2268,7 +2323,7 @@ void ModelVolume::scale(const Vec3d& scaling_factors)
 
 void ModelObject::scale_to_fit(const Vec3d &size)
 {
-    Vec3d orig_size = this->bounding_box().size();
+    Vec3d orig_size = this->bounding_box_exact().size();
     double factor = std::min(
         size.x() / orig_size.x(),
         std::min(
@@ -2373,37 +2428,6 @@ void ModelInstance::transform_mesh(TriangleMesh* mesh, bool dont_translate) cons
 #endif // ENABLE_WORLD_COORDINATE
 }
 
-BoundingBoxf3 ModelInstance::transform_mesh_bounding_box(const TriangleMesh& mesh, bool dont_translate) const
-{
-    // Rotate around mesh origin.
-    TriangleMesh copy(mesh);
-#if ENABLE_WORLD_COORDINATE
-    copy.transform(get_transformation().get_rotation_matrix());
-#else
-    copy.transform(get_matrix(true, false, true, true));
-#endif // ENABLE_WORLD_COORDINATE
-    BoundingBoxf3 bbox = copy.bounding_box();
-
-    if (!empty(bbox)) {
-        // Scale the bounding box along the three axes.
-        for (unsigned int i = 0; i < 3; ++i)
-        {
-            if (std::abs(get_scaling_factor((Axis)i)-1.0) > EPSILON)
-            {
-                bbox.min(i) *= get_scaling_factor((Axis)i);
-                bbox.max(i) *= get_scaling_factor((Axis)i);
-            }
-        }
-
-        // Translate the bounding box.
-        if (! dont_translate) {
-            bbox.min += get_offset();
-            bbox.max += get_offset();
-        }
-    }
-    return bbox;
-}
-
 BoundingBoxf3 ModelInstance::transform_bounding_box(const BoundingBoxf3 &bbox, bool dont_translate) const
 {
 #if ENABLE_WORLD_COORDINATE

src/libslic3r/Model.hpp

@@ -168,7 +168,7 @@ private:
 	friend class cereal::access;
 	friend class UndoRedo::StackImpl;
 	// Create an object for deserialization, don't allocate IDs for ModelMaterial and its config.
-	ModelMaterial() : ObjectBase(-1), config(-1), m_model(nullptr) { assert(this->id().invalid()); assert(this->config.id().invalid()); }
+	ModelMaterial() : ObjectBase(-1), config(-1) { assert(this->id().invalid()); assert(this->config.id().invalid()); }
 	template<class Archive> void serialize(Archive &ar) { 
 		assert(this->id().invalid()); assert(this->config.id().invalid());
 		Internal::StaticSerializationWrapper<ModelConfigObject> config_wrapper(config);
@@ -343,7 +343,7 @@ public:
     // The pairs of <z, layer_height> are packed into a 1D array.
     LayerHeightProfile      layer_height_profile;
     // Whether or not this object is printable
-    bool                    printable;
+    bool                    printable { true };
 
     // This vector holds position of selected support points for SLA. The data are
     // saved in mesh coordinates to allow using them for several instances.
@@ -397,11 +397,22 @@ public:
     void                    delete_last_instance();
     void                    clear_instances();
 
-    // Returns the bounding box of the transformed instances.
+    // Returns the bounding box of the transformed instances. This bounding box is approximate and not snug, it is being cached.
-    // This bounding box is approximate and not snug.
+    const BoundingBoxf3&    bounding_box_approx() const;
-    // This bounding box is being cached.
+    // Returns an exact bounding box of the transformed instances. The result it is being cached.
-    const BoundingBoxf3& bounding_box() const;
+    const BoundingBoxf3&    bounding_box_exact() const;
-    void invalidate_bounding_box() { m_bounding_box_valid = false; m_raw_bounding_box_valid = false; m_raw_mesh_bounding_box_valid = false; }
+    // Return minimum / maximum of a printable object transformed into the world coordinate system.
+    // All instances share the same min / max Z.
+    double                  min_z() const;
+    double                  max_z() const;
+
+    void invalidate_bounding_box() { 
+        m_bounding_box_approx_valid     = false;
+        m_bounding_box_exact_valid      = false;
+        m_min_max_z_valid               = false;
+        m_raw_bounding_box_valid        = false;
+        m_raw_mesh_bounding_box_valid   = false;
+    }
 
     // A mesh containing all transformed instances of this object.
     TriangleMesh mesh() const;
@@ -477,8 +488,6 @@ public:
     // Rotation and mirroring is being baked in. In case the instance scaling was non-uniform, it is baked in as well.
     void bake_xy_rotation_into_meshes(size_t instance_idx);
 
-    double get_min_z() const;
-    double get_max_z() const;
     double get_instance_min_z(size_t instance_idx) const;
     double get_instance_max_z(size_t instance_idx) const;
 
@@ -500,14 +509,13 @@ public:
 private:
     friend class Model;
     // This constructor assigns new ID to this ModelObject and its config.
-    explicit ModelObject(Model* model) : m_model(model), printable(true), origin_translation(Vec3d::Zero()),
+    explicit ModelObject(Model* model) : m_model(model), origin_translation(Vec3d::Zero())
-        m_bounding_box_valid(false), m_raw_bounding_box_valid(false), m_raw_mesh_bounding_box_valid(false)
     { 
         assert(this->id().valid());
         assert(this->config.id().valid());
         assert(this->layer_height_profile.id().valid());
     }
-    explicit ModelObject(int) : ObjectBase(-1), config(-1), layer_height_profile(-1), m_model(nullptr), printable(true), origin_translation(Vec3d::Zero()), m_bounding_box_valid(false), m_raw_bounding_box_valid(false), m_raw_mesh_bounding_box_valid(false)
+    explicit ModelObject(int) : ObjectBase(-1), config(-1), layer_height_profile(-1), origin_translation(Vec3d::Zero())
     { 
         assert(this->id().invalid()); 
         assert(this->config.id().invalid());
@@ -585,15 +593,18 @@ private:
     OBJECTBASE_DERIVED_COPY_MOVE_CLONE(ModelObject)
 
     // Parent object, owning this ModelObject. Set to nullptr here, so the macros above will have it initialized.
-    Model                *m_model = nullptr;
+    Model                *m_model { nullptr };
 
     // Bounding box, cached.
-    mutable BoundingBoxf3 m_bounding_box;
+    mutable BoundingBoxf3 m_bounding_box_approx;
-    mutable bool          m_bounding_box_valid;
+    mutable bool          m_bounding_box_approx_valid { false };
+    mutable BoundingBoxf3 m_bounding_box_exact;
+    mutable bool          m_bounding_box_exact_valid { false };
+    mutable bool          m_min_max_z_valid { false };
     mutable BoundingBoxf3 m_raw_bounding_box;
-    mutable bool          m_raw_bounding_box_valid;
+    mutable bool          m_raw_bounding_box_valid { false };
     mutable BoundingBoxf3 m_raw_mesh_bounding_box;
-    mutable bool          m_raw_mesh_bounding_box_valid;
+    mutable bool          m_raw_mesh_bounding_box_valid { false };
 
     // Called by Print::apply() to set the model pointer after making a copy.
     friend class Print;
@@ -605,8 +616,7 @@ private:
 	friend class UndoRedo::StackImpl;
 	// Used for deserialization -> Don't allocate any IDs for the ModelObject or its config.
 	ModelObject() : 
-        ObjectBase(-1), config(-1), layer_height_profile(-1),
+        ObjectBase(-1), config(-1), layer_height_profile(-1) {
-        m_model(nullptr), m_bounding_box_valid(false), m_raw_bounding_box_valid(false), m_raw_mesh_bounding_box_valid(false) {
 		assert(this->id().invalid()); 
         assert(this->config.id().invalid());
         assert(this->layer_height_profile.id().invalid());
@@ -617,12 +627,17 @@ private:
         Internal::StaticSerializationWrapper<LayerHeightProfile> layer_heigth_profile_wrapper(layer_height_profile);
         ar(name, input_file, instances, volumes, config_wrapper, layer_config_ranges, layer_heigth_profile_wrapper, 
             sla_support_points, sla_points_status, sla_drain_holes, printable, origin_translation,
-            m_bounding_box, m_bounding_box_valid, m_raw_bounding_box, m_raw_bounding_box_valid, m_raw_mesh_bounding_box, m_raw_mesh_bounding_box_valid,
+            m_bounding_box_approx, m_bounding_box_approx_valid, 
+            m_bounding_box_exact, m_bounding_box_exact_valid, m_min_max_z_valid,
+            m_raw_bounding_box, m_raw_bounding_box_valid, m_raw_mesh_bounding_box, m_raw_mesh_bounding_box_valid,
             cut_connectors, cut_id);
 	}
 
     // Called by Print::validate() from the UI thread.
     unsigned int update_instances_print_volume_state(const BuildVolume &build_volume);
+
+    // Called by min_z(), max_z()
+    void update_min_max_z();
 };
 
 enum class EnforcerBlockerType : int8_t {
@@ -1106,7 +1121,7 @@ public:
     // flag showing the position of this instance with respect to the print volume (set by Print::validate() using ModelObject::check_instances_print_volume_state())
     ModelInstanceEPrintVolumeState print_volume_state;
     // Whether or not this instance is printable
-    bool printable;
+    bool printable { true };
 
     ModelObject* get_object() const { return this->object; }
 
@@ -1156,9 +1171,7 @@ public:
 
     // To be called on an external mesh
     void transform_mesh(TriangleMesh* mesh, bool dont_translate = false) const;
-    // Calculate a bounding box of a transformed mesh. To be called on an external mesh.
+    // Transform an external bounding box, thus the resulting bounding box is no more snug.
-    BoundingBoxf3 transform_mesh_bounding_box(const TriangleMesh& mesh, bool dont_translate = false) const;
-    // Transform an external bounding box.
     BoundingBoxf3 transform_bounding_box(const BoundingBoxf3 &bbox, bool dont_translate = false) const;
     // Transform an external vector.
     Vec3d transform_vector(const Vec3d& v, bool dont_translate = false) const;
@@ -1201,7 +1214,7 @@ private:
     ModelObject* object;
 
     // Constructor, which assigns a new unique ID.
-    explicit ModelInstance(ModelObject* object) : print_volume_state(ModelInstancePVS_Inside), printable(true), object(object) { assert(this->id().valid()); }
+    explicit ModelInstance(ModelObject* object) : print_volume_state(ModelInstancePVS_Inside), object(object) { assert(this->id().valid()); }
     // Constructor, which assigns a new unique ID.
     explicit ModelInstance(ModelObject *object, const ModelInstance &other) :
         m_transformation(other.m_transformation), print_volume_state(ModelInstancePVS_Inside), printable(other.printable), object(object) { assert(this->id().valid() && this->id() != other.id()); }
@@ -1316,8 +1329,12 @@ public:
     void          delete_material(t_model_material_id material_id);
     void          clear_materials();
     bool          add_default_instances();
-    // Returns approximate axis aligned bounding box of this model
+    // Returns approximate axis aligned bounding box of this model.
-    BoundingBoxf3 bounding_box() const;
+    BoundingBoxf3 bounding_box_approx() const;
+    // Returns exact axis aligned bounding box of this model.
+    BoundingBoxf3 bounding_box_exact() const;
+    // Return maximum height of all printable objects.
+    double        max_z() const;
     // Set the print_volume_state of PrintObject::instances, 
     // return total number of printable objects.
     unsigned int  update_print_volume_state(const BuildVolume &build_volume);

src/libslic3r/PrintObject.cpp

@@ -77,7 +77,7 @@ PrintObject::PrintObject(Print* print, ModelObject* model_object, const Transfor
     Vec3d 		   bbox_center = bbox.center();
 	// We may need to rotate the bbox / bbox_center from the original instance to the current instance.
     double z_diff = Geometry::rotation_diff_z(model_object->instances.front()->get_matrix(), instances.front().model_instance->get_matrix());
-  if (std::abs(z_diff) > EPSILON) {
+    if (std::abs(z_diff) > EPSILON) {
 		auto z_rot  = Eigen::AngleAxisd(z_diff, Vec3d::UnitZ());
 		bbox 		= bbox.transformed(Transform3d(z_rot));
 		bbox_center = (z_rot * bbox_center).eval();
@@ -87,6 +87,7 @@ PrintObject::PrintObject(Print* print, ModelObject* model_object, const Transfor
     m_center_offset = Point::new_scale(bbox_center.x(), bbox_center.y());
     // Size of the transformed mesh. This bounding may not be snug in XY plane, but it is snug in Z.
     m_size = (bbox.size() * (1. / SCALING_FACTOR)).cast<coord_t>();
+    m_size.z() = model_object->max_z();
 
     this->set_instances(std::move(instances));
 }
@@ -1736,7 +1737,7 @@ void PrintObject::update_slicing_parameters()
 {
     if (!m_slicing_params.valid)
         m_slicing_params = SlicingParameters::create_from_config(
-            this->print()->config(), m_config, this->model_object()->bounding_box().max.z(), this->object_extruders());
+            this->print()->config(), m_config, this->model_object()->max_z(), this->object_extruders());
 }
 
 SlicingParameters PrintObject::slicing_parameters(const DynamicPrintConfig& full_config, const ModelObject& model_object, float object_max_z)

src/slic3r/GUI/GCodeViewer.cpp

@@ -2246,7 +2246,7 @@ void GCodeViewer::load_shells(const Print& print)
 
     if (wxGetApp().preset_bundle->printers.get_edited_preset().printer_technology() == ptFFF) {
         // adds wipe tower's volume
-        const double max_z = print.objects()[0]->model_object()->get_model()->bounding_box().max(2);
+        const double max_z = print.objects()[0]->model_object()->get_model()->max_z();
         const PrintConfig& config = print.config();
         const size_t extruders_count = config.nozzle_diameter.size();
         if (extruders_count > 1 && config.wipe_tower && !config.complete_objects) {

src/slic3r/GUI/GLCanvas3D.cpp

@@ -140,7 +140,7 @@ void GLCanvas3D::LayersEditing::select_object(const Model &model, int object_id)
     // Maximum height of an object changes when the object gets rotated or scaled.
     // Changing maximum height of an object will invalidate the layer heigth editing profile.
     // m_model_object->bounding_box() is cached, therefore it is cheap even if this method is called frequently.
-    const float new_max_z = (model_object_new == nullptr) ? 0.0f : static_cast<float>(model_object_new->bounding_box().max.z());
+    const float new_max_z = (model_object_new == nullptr) ? 0.0f : static_cast<float>(model_object_new->max_z());
     if (m_model_object != model_object_new || this->last_object_id != object_id || m_object_max_z != new_max_z ||
         (model_object_new != nullptr && m_model_object->id() != model_object_new->id())) {
         m_layer_height_profile.clear();
@@ -1977,7 +1977,7 @@ void GLCanvas3D::reload_scene(bool refresh_immediately, bool force_full_scene_re
 
         if (extruders_count > 1 && wt && !co) {
             // Height of a print (Show at least a slab)
-            const double height = std::max(m_model->bounding_box().max.z(), 10.0);
+            const double height = std::max(m_model->max_z(), 10.0);
 
             const float x = dynamic_cast<const ConfigOptionFloat*>(m_config->option("wipe_tower_x"))->value;
             const float y = dynamic_cast<const ConfigOptionFloat*>(m_config->option("wipe_tower_y"))->value;

src/slic3r/GUI/Plater.cpp

@@ -3520,7 +3520,7 @@ bool Plater::priv::replace_volume_with_stl(int object_idx, int volume_idx, const
     ModelObject* old_model_object = model.objects[object_idx];
     ModelVolume* old_volume = old_model_object->volumes[volume_idx];
 
-    bool sinking = old_model_object->bounding_box().min.z() < SINKING_Z_THRESHOLD;
+    bool sinking = old_model_object->min_z() < SINKING_Z_THRESHOLD;
 
     ModelObject* new_model_object = new_model.objects.front();
     old_model_object->add_volume(*new_model_object->volumes.front());
@@ -3835,7 +3835,7 @@ void Plater::priv::reload_from_disk()
             ModelObject* old_model_object = model.objects[obj_idx];
             ModelVolume* old_volume = old_model_object->volumes[vol_idx];
 
-            bool sinking = old_model_object->bounding_box().min.z() < SINKING_Z_THRESHOLD;
+            bool sinking = old_model_object->min_z() < SINKING_Z_THRESHOLD;
 
             bool has_source = !old_volume->source.input_file.empty() && boost::algorithm::iequals(fs::path(old_volume->source.input_file).filename().string(), fs::path(path).filename().string());
             bool has_name = !old_volume->name.empty() && boost::algorithm::iequals(old_volume->name, fs::path(path).filename().string());
@@ -4816,7 +4816,7 @@ bool Plater::priv::layers_height_allowed() const
         return false;
 
     int obj_idx = get_selected_object_idx();
-    return 0 <= obj_idx && obj_idx < (int)model.objects.size() && model.objects[obj_idx]->bounding_box().max.z() > SINKING_Z_THRESHOLD &&
+    return 0 <= obj_idx && obj_idx < (int)model.objects.size() && model.objects[obj_idx]->max_z() > SINKING_Z_THRESHOLD &&
         config->opt_bool("variable_layer_height") && view3D->is_layers_editing_allowed();
 }
 
@@ -7435,7 +7435,7 @@ void Plater::changed_objects(const std::vector<size_t>& object_idxs)
 
     for (size_t obj_idx : object_idxs) {
         if (obj_idx < p->model.objects.size()) {
-            if (p->model.objects[obj_idx]->bounding_box().min.z() >= SINKING_Z_THRESHOLD)
+            if (p->model.objects[obj_idx]->min_z() >= SINKING_Z_THRESHOLD)
                 // re - align to Z = 0
                 p->model.objects[obj_idx]->ensure_on_bed();
         }