1st installment of ModelInstance 3D rotation components

lib/Slic3r/GUI/Plater.pm

@@ -150,12 +150,64 @@ sub new {
         $self->rotate(rad2deg($angle), Z, 'absolute');
     };
     
+    # callback to react to gizmo rotate
+    my $on_gizmo_rotate_3D = sub {
+        my ($angle_x, $angle_y, $angle_z) = @_;
+
+        my ($obj_idx, $object) = $self->selected_object;
+        return if !defined $obj_idx;
+
+        my $model_object = $self->{model}->objects->[$obj_idx];
+        my $model_instance = $model_object->instances->[0];
+
+        $self->stop_background_process;
+
+        my $rotation = Slic3r::Pointf3->new($angle_x, $angle_y, $angle_z);
+        foreach my $inst (@{ $model_object->instances }) {
+            $inst->set_rotations($rotation);
+        }
+        Slic3r::GUI::_3DScene::update_gizmos_data($self->{canvas3D}) if ($self->{canvas3D});  
+    
+        # update print and start background processing
+        $self->{print}->add_model_object($model_object, $obj_idx);
+    
+        $self->selection_changed;  # refresh info (size etc.)
+        $self->update;
+        $self->schedule_background_process;
+    };
+    
     # callback to react to gizmo flatten
     my $on_gizmo_flatten = sub {
         my ($angle, $axis_x, $axis_y, $axis_z) = @_;
         $self->rotate(rad2deg($angle), undef, 'absolute', $axis_x, $axis_y, $axis_z) if $angle != 0;
     };
 
+    # callback to react to gizmo flatten
+    my $on_gizmo_flatten_3D = sub {
+        my ($angle_x, $angle_y, $angle_z) = @_;
+
+        my ($obj_idx, $object) = $self->selected_object;
+        return if !defined $obj_idx;
+
+        my $model_object = $self->{model}->objects->[$obj_idx];
+        my $model_instance = $model_object->instances->[0];
+
+        $self->stop_background_process;
+
+        my $rotation = Slic3r::Pointf3->new($angle_x, $angle_y, $angle_z);
+        foreach my $inst (@{ $model_object->instances }) {
+            $inst->set_rotations($rotation);
+        }
+        Slic3r::GUI::_3DScene::update_gizmos_data($self->{canvas3D}) if ($self->{canvas3D});  
+    
+        # update print and start background processing
+        $self->{print}->add_model_object($model_object, $obj_idx);
+    
+        $self->selection_changed;  # refresh info (size etc.)
+        $self->update;
+        $self->schedule_background_process;
+    };
+    
     # callback to update object's geometry info while using gizmos
     my $on_update_geometry_info = sub {
         my ($size_x, $size_y, $size_z, $scale_factor) = @_;
@@ -261,7 +313,9 @@ sub new {
         Slic3r::GUI::_3DScene::register_on_enable_action_buttons_callback($self->{canvas3D}, $enable_action_buttons);
         Slic3r::GUI::_3DScene::register_on_gizmo_scale_uniformly_callback($self->{canvas3D}, $on_gizmo_scale_uniformly);
         Slic3r::GUI::_3DScene::register_on_gizmo_rotate_callback($self->{canvas3D}, $on_gizmo_rotate);
+        Slic3r::GUI::_3DScene::register_on_gizmo_rotate_3D_callback($self->{canvas3D}, $on_gizmo_rotate_3D);
         Slic3r::GUI::_3DScene::register_on_gizmo_flatten_callback($self->{canvas3D}, $on_gizmo_flatten);
+        Slic3r::GUI::_3DScene::register_on_gizmo_flatten_3D_callback($self->{canvas3D}, $on_gizmo_flatten_3D);
         Slic3r::GUI::_3DScene::register_on_update_geometry_info_callback($self->{canvas3D}, $on_update_geometry_info);
         Slic3r::GUI::_3DScene::register_action_add_callback($self->{canvas3D}, $on_action_add);
         Slic3r::GUI::_3DScene::register_action_delete_callback($self->{canvas3D}, $on_action_delete);

xs/src/libslic3r/Format/3mf.cpp

@@ -1283,6 +1283,9 @@ namespace Slic3r {
                 transform(1, 0) * inv_sx, transform(1, 1) * inv_sy, transform(1, 2) * inv_sz,
                 transform(2, 0) * inv_sx, transform(2, 1) * inv_sy, transform(2, 2) * inv_sz;
 
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+        Vec3d rotation = m3x3.eulerAngles(0, 1, 2);
+#else
         Eigen::AngleAxisd rotation;
         rotation.fromRotationMatrix(m3x3);
 
@@ -1291,6 +1294,7 @@ namespace Slic3r {
             return;
 
         double angle_z = (rotation.axis() == Vec3d::UnitZ()) ? rotation.angle() : -rotation.angle();
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 
 #if ENABLE_MODELINSTANCE_3D_OFFSET
         instance.set_offset(offset);
@@ -1299,7 +1303,11 @@ namespace Slic3r {
         instance.offset(1) = offset_y;
 #endif // ENABLE_MODELINSTANCE_3D_OFFSET
         instance.scaling_factor = sx;
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+        instance.set_rotation(rotation);
+#else
         instance.rotation = angle_z;
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
     }
 
     bool _3MF_Importer::_handle_start_config(const char** attributes, unsigned int num_attributes)

xs/src/libslic3r/Format/AMF.cpp

@@ -30,7 +30,12 @@
 // 0 : .amf, .amf.xml and .zip.amf files saved by older slic3r. No version definition in them.
 // 1 : Introduction of amf versioning. No other change in data saved into amf files.
 #if ENABLE_MODELINSTANCE_3D_OFFSET
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+// 2 : Added z component of offset
+//     Added x and y components of rotation
+#else
 // 2 : Added z component of offset.
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 const unsigned int VERSION_AMF = 2;
 #else
 const unsigned int VERSION_AMF = 1;
@@ -127,6 +132,10 @@ struct AMFParserContext
 #if ENABLE_MODELINSTANCE_3D_OFFSET
         NODE_TYPE_DELTAZ,               // amf/constellation/instance/deltaz
 #endif // ENABLE_MODELINSTANCE_3D_OFFSET
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+        NODE_TYPE_RX,                   // amf/constellation/instance/rx
+        NODE_TYPE_RY,                   // amf/constellation/instance/ry
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
         NODE_TYPE_RZ,                   // amf/constellation/instance/rz
         NODE_TYPE_SCALE,                // amf/constellation/instance/scale
         NODE_TYPE_METADATA,             // anywhere under amf/*/metadata
@@ -134,7 +143,11 @@ struct AMFParserContext
 
     struct Instance {
 #if ENABLE_MODELINSTANCE_3D_OFFSET
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+        Instance() : deltax_set(false), deltay_set(false), deltaz_set(false), rx_set(false), ry_set(false), rz_set(false), scale_set(false) {}
+#else
         Instance() : deltax_set(false), deltay_set(false), deltaz_set(false), rz_set(false), scale_set(false) {}
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 #else
         Instance() : deltax_set(false), deltay_set(false), rz_set(false), scale_set(false) {}
 #endif // ENABLE_MODELINSTANCE_3D_OFFSET
@@ -149,6 +162,14 @@ struct AMFParserContext
         float deltaz;
         bool  deltaz_set;
 #endif // ENABLE_MODELINSTANCE_3D_OFFSET
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+        // Rotation around the X axis.
+        float rx;
+        bool  rx_set;
+        // Rotation around the Y axis.
+        float ry;
+        bool  ry_set;
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
         // Rotation around the Z axis.
         float rz;
         bool  rz_set;
@@ -275,6 +296,12 @@ void AMFParserContext::startElement(const char *name, const char **atts)
             else if (strcmp(name, "deltaz") == 0)
                 node_type_new = NODE_TYPE_DELTAZ;
 #endif // ENABLE_MODELINSTANCE_3D_OFFSET
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+            else if (strcmp(name, "rx") == 0)
+                node_type_new = NODE_TYPE_RX;
+            else if (strcmp(name, "ry") == 0)
+                node_type_new = NODE_TYPE_RY;
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
             else if (strcmp(name, "rz") == 0)
                 node_type_new = NODE_TYPE_RZ;
             else if (strcmp(name, "scale") == 0)
@@ -339,7 +366,11 @@ void AMFParserContext::characters(const XML_Char *s, int len)
             if (m_path.back() == NODE_TYPE_DELTAX || 
                 m_path.back() == NODE_TYPE_DELTAY || 
                 m_path.back() == NODE_TYPE_DELTAZ || 
-                m_path.back() == NODE_TYPE_RZ || 
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+                m_path.back() == NODE_TYPE_RX ||
+                m_path.back() == NODE_TYPE_RY ||
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
+                m_path.back() == NODE_TYPE_RZ ||
                 m_path.back() == NODE_TYPE_SCALE)
 #else
             if (m_path.back() == NODE_TYPE_DELTAX || m_path.back() == NODE_TYPE_DELTAY || m_path.back() == NODE_TYPE_RZ || m_path.back() == NODE_TYPE_SCALE)
@@ -391,6 +422,20 @@ void AMFParserContext::endElement(const char * /* name */)
         m_value[0].clear();
         break;
 #endif // ENABLE_MODELINSTANCE_3D_OFFSET
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    case NODE_TYPE_RX:
+        assert(m_instance);
+        m_instance->rx = float(atof(m_value[0].c_str()));
+        m_instance->rx_set = true;
+        m_value[0].clear();
+        break;
+    case NODE_TYPE_RY:
+        assert(m_instance);
+        m_instance->ry = float(atof(m_value[0].c_str()));
+        m_instance->ry_set = true;
+        m_value[0].clear();
+        break;
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
     case NODE_TYPE_RZ:
         assert(m_instance);
         m_instance->rz = float(atof(m_value[0].c_str()));
@@ -541,12 +586,16 @@ void AMFParserContext::endDocument()
             if (instance.deltax_set && instance.deltay_set) {
                 ModelInstance *mi = m_model.objects[object.second.idx]->add_instance();
 #if ENABLE_MODELINSTANCE_3D_OFFSET
-                mi->set_offset(Vec3d((double)instance.deltax, (double)instance.deltay, (double)instance.deltaz));
+                mi->set_offset(Vec3d(instance.deltax_set ? (double)instance.deltax : 0.0, instance.deltay_set ? (double)instance.deltay : 0.0, instance.deltaz_set ? (double)instance.deltaz : 0.0));
 #else
                 mi->offset(0) = instance.deltax;
                 mi->offset(1) = instance.deltay;
 #endif // ENABLE_MODELINSTANCE_3D_OFFSET
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+                mi->set_rotation(Vec3d(instance.rx_set ? (double)instance.rx : 0.0, instance.ry_set ? (double)instance.ry : 0.0, instance.rz_set ? (double)instance.rz : 0.0));
+#else
                 mi->rotation = instance.rz_set ? instance.rz : 0.f;
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
                 mi->scaling_factor = instance.scale_set ? instance.scale : 1.f;
             }
     }
@@ -850,6 +899,10 @@ bool store_amf(const char *path, Model *model, Print* print, bool export_print_c
 #if ENABLE_MODELINSTANCE_3D_OFFSET
                     "      <deltaz>%lf</deltaz>\n"
 #endif // ENABLE_MODELINSTANCE_3D_OFFSET
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+                    "      <rx>%lf</rx>\n"
+                    "      <ry>%lf</ry>\n"
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
                     "      <rz>%lf</rz>\n"
                     "      <scale>%lf</scale>\n"
                     "    </instance>\n",
@@ -862,8 +915,15 @@ bool store_amf(const char *path, Model *model, Print* print, bool export_print_c
                     instance->offset(0),
                     instance->offset(1),
 #endif // ENABLE_MODELINSTANCE_3D_OFFSET
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+                    instance->get_rotation(X),
+                    instance->get_rotation(Y),
+                    instance->get_rotation(Z),
+#else
                     instance->rotation,
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
                     instance->scaling_factor);
+
                 //FIXME missing instance->scaling_factor
                 instances.append(buf);
             }

xs/src/libslic3r/Format/PRUS.cpp

@@ -164,7 +164,11 @@ bool load_prus(const char *path, Model *model)
             const char *zero_tag  = "<zero>";
 			const char *zero_xml  = strstr(scene_xml_data.data(), zero_tag);
             float  trafo[3][4] = { 0 };
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+            Vec3d instance_rotation = Vec3d::Zero();
+#else
             double instance_rotation = 0.;
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
             double instance_scaling_factor = 1.f;
 #if ENABLE_MODELINSTANCE_3D_OFFSET
             Vec3d instance_offset = Vec3d::Zero();
@@ -197,10 +201,14 @@ bool load_prus(const char *path, Model *model)
                         instance_scaling_factor = scale[0];
                         scale[0] = scale[1] = scale[2] = 1.;
                     }
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+                    instance_rotation = Vec3d(-(double)rotation[0], -(double)rotation[1], -(double)rotation[2]);
+#else
                     if (rotation[0] == 0. && rotation[1] == 0.) {
                         instance_rotation = - rotation[2];
                         rotation[2] = 0.;
                     }
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
                     Eigen::Matrix3f mat_rot, mat_scale, mat_trafo;
                     mat_rot = Eigen::AngleAxisf(-rotation[2], Eigen::Vector3f::UnitZ()) * 
                               Eigen::AngleAxisf(-rotation[1], Eigen::Vector3f::UnitY()) *
@@ -366,8 +374,12 @@ bool load_prus(const char *path, Model *model)
                         model_object = model->add_object(name_utf8.data(), path, std::move(mesh));
                         volume = model_object->volumes.front();
                         ModelInstance *instance     = model_object->add_instance();
-                        instance->rotation          = instance_rotation;
+#if ENABLE_MODELINSTANCE_3D_ROTATION
-                        instance->scaling_factor    = instance_scaling_factor;
+                        instance->set_rotation(instance_rotation);
+#else
+                        instance->rotation = instance_rotation;
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
+                        instance->scaling_factor = instance_scaling_factor;
 #if ENABLE_MODELINSTANCE_3D_OFFSET
                         instance->set_offset(instance_offset);
 #else

xs/src/libslic3r/Model.cpp

@@ -1054,6 +1054,29 @@ size_t ModelVolume::split(unsigned int max_extruders)
     return idx;
 }
 
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+void ModelInstance::set_rotation(const Vec3d& rotation)
+{
+    set_rotation(X, rotation(0));
+    set_rotation(Y, rotation(1));
+    set_rotation(Z, rotation(2));
+}
+
+void ModelInstance::set_rotation(Axis axis, double rotation)
+{
+    static const double TWO_PI = 2.0 * (double)PI;
+    while (rotation < 0.0)
+    {
+        rotation += TWO_PI;
+    }
+    while (TWO_PI < rotation)
+    {
+        rotation -= TWO_PI;
+    }
+    m_rotation(axis) = rotation;
+}
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
+
 void ModelInstance::transform_mesh(TriangleMesh* mesh, bool dont_translate) const
 {
     mesh->transform(world_matrix(dont_translate).cast<float>());
@@ -1098,7 +1121,12 @@ Vec3d ModelInstance::transform_vector(const Vec3d& v, bool dont_translate) const
 
 void ModelInstance::transform_polygon(Polygon* polygon) const
 {
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    // CHECK_ME -> Is the following correct or it should take in account all three rotations ?
+    polygon->rotate(this->m_rotation(2));                // rotate around polygon origin
+#else
     polygon->rotate(this->rotation);                // rotate around polygon origin
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
     polygon->scale(this->scaling_factor);           // scale around polygon origin
 }
 
@@ -1114,7 +1142,15 @@ Transform3d ModelInstance::world_matrix(bool dont_translate, bool dont_rotate, b
 #endif // ENABLE_MODELINSTANCE_3D_OFFSET
 
     if (!dont_rotate)
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    {
+        m.rotate(Eigen::AngleAxisd(m_rotation(2), Vec3d::UnitZ()));
+        m.rotate(Eigen::AngleAxisd(m_rotation(1), Vec3d::UnitY()));
+        m.rotate(Eigen::AngleAxisd(m_rotation(0), Vec3d::UnitX()));
+    }
+#else
         m.rotate(Eigen::AngleAxisd(rotation, Vec3d::UnitZ()));
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 
     if (!dont_scale)
         m.scale(scaling_factor);

xs/src/libslic3r/Model.hpp

@@ -246,11 +246,16 @@ public:
 #if ENABLE_MODELINSTANCE_3D_OFFSET
 private:
     Vec3d m_offset;              // in unscaled coordinates
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    Vec3d m_rotation;            // Rotation around the three axes, in radians around mesh center point
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 
 public:
 #endif // ENABLE_MODELINSTANCE_3D_OFFSET
 
+#if !ENABLE_MODELINSTANCE_3D_ROTATION
     double rotation;            // Rotation around the Z axis, in radians around mesh center point
+#endif // !ENABLE_MODELINSTANCE_3D_ROTATION
     double scaling_factor;
 #if !ENABLE_MODELINSTANCE_3D_OFFSET
     Vec2d offset;              // in unscaled coordinates
@@ -269,6 +274,14 @@ public:
     void set_offset(Axis axis, double offset) { m_offset(axis) = offset; }
 #endif // ENABLE_MODELINSTANCE_3D_OFFSET
 
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    const Vec3d& get_rotation() const { return m_rotation; }
+    double get_rotation(Axis axis) const { return m_rotation(axis); }
+
+    void set_rotation(const Vec3d& rotation);
+    void set_rotation(Axis axis, double rotation);
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
+
     // 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.
@@ -289,9 +302,15 @@ private:
     ModelObject* object;
 
 #if ENABLE_MODELINSTANCE_3D_OFFSET
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    ModelInstance(ModelObject *object) : m_rotation(Vec3d::Zero()), scaling_factor(1), m_offset(Vec3d::Zero()), object(object), print_volume_state(PVS_Inside) {}
+    ModelInstance(ModelObject *object, const ModelInstance &other) :
+        m_rotation(other.m_rotation), scaling_factor(other.scaling_factor), m_offset(other.m_offset), object(object), print_volume_state(PVS_Inside) {}
+#else
     ModelInstance(ModelObject *object) : rotation(0), scaling_factor(1), m_offset(Vec3d::Zero()), object(object), print_volume_state(PVS_Inside) {}
     ModelInstance(ModelObject *object, const ModelInstance &other) :
         rotation(other.rotation), scaling_factor(other.scaling_factor), m_offset(other.m_offset), object(object), print_volume_state(PVS_Inside) {}
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 #else
     ModelInstance(ModelObject *object) : rotation(0), scaling_factor(1), offset(Vec2d::Zero()), object(object), print_volume_state(PVS_Inside) {}
     ModelInstance(ModelObject *object, const ModelInstance &other) :

xs/src/libslic3r/ModelArrange.hpp

@@ -527,8 +527,13 @@ ShapeData2D projectModelFromTop(const Slic3r::Model &model) {
 
                     // Invalid geometries would throw exceptions when arranging
                     if(item.vertexCount() > 3) {
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+                        // CHECK_ME -> is the following correct or it should take in account all three rotations ?
+                        item.rotation(objinst->get_rotation(Z));
+#else
                         item.rotation(objinst->rotation);
-                        item.translation( {
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
+                        item.translation({
 #if ENABLE_MODELINSTANCE_3D_OFFSET
                         ClipperLib::cInt(objinst->get_offset(X)/SCALING_FACTOR),
                         ClipperLib::cInt(objinst->get_offset(Y)/SCALING_FACTOR)
@@ -681,7 +686,12 @@ void applyResult(
 #endif // ENABLE_MODELINSTANCE_3D_OFFSET
 
         // write the transformation data into the model instance
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+        // CHECK_ME -> Is the following correct ?
+        inst_ptr->set_rotation(Vec3d(0.0, 0.0, rot));
+#else
         inst_ptr->rotation = rot;
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 #if ENABLE_MODELINSTANCE_3D_OFFSET
         inst_ptr->set_offset(foff);
 #else

xs/src/libslic3r/Technologies.hpp

@@ -8,6 +8,8 @@
 #define ENABLE_MODELINSTANCE_3D_OFFSET (1 && ENABLE_1_42_0)
 // Add double click on gizmo grabbers to reset transformation components to their default value
 #define ENABLE_GIZMOS_RESET (1 && ENABLE_1_42_0)
+// Add x and y rotation components to model instances' offset
+#define ENABLE_MODELINSTANCE_3D_ROTATION (1 && ENABLE_MODELINSTANCE_3D_OFFSET)
 
 #endif // _technologies_h_
 

xs/src/slic3r/GUI/3DScene.cpp

@@ -196,7 +196,11 @@ const float GLVolume::SELECTED_OUTSIDE_COLOR[4] = { 0.19f, 0.58f, 1.0f, 1.0f };
 
 GLVolume::GLVolume(float r, float g, float b, float a)
     : m_offset(Vec3d::Zero())
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    , m_rotation(Vec3d::Zero())
+#else
     , m_rotation(0.0)
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
     , m_scaling_factor(1.0)
     , m_world_matrix(Transform3f::Identity())
     , m_world_matrix_dirty(true)
@@ -255,7 +259,24 @@ void GLVolume::set_render_color()
         set_render_color(color, 4);
 }
 
-double GLVolume::get_rotation()
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+const Vec3d& GLVolume::get_rotation() const
+{
+    return m_rotation;
+}
+
+void GLVolume::set_rotation(const Vec3d& rotation)
+{
+    if (m_rotation != rotation)
+    {
+        m_rotation = rotation;
+        m_world_matrix_dirty = true;
+        m_transformed_bounding_box_dirty = true;
+        m_transformed_convex_hull_bounding_box_dirty = true;
+    }
+}
+#else
+double GLVolume::get_rotation() const
 {
     return m_rotation;
 }
@@ -270,6 +291,7 @@ void GLVolume::set_rotation(double rotation)
         m_transformed_convex_hull_bounding_box_dirty = true;
     }
 }
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 
 const Vec3d& GLVolume::get_offset() const
 {
@@ -327,7 +349,13 @@ const Transform3f& GLVolume::world_matrix() const
     {
         m_world_matrix = Transform3f::Identity();
         m_world_matrix.translate(m_offset.cast<float>());
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+        m_world_matrix.rotate(Eigen::AngleAxisf((float)m_rotation(2), Vec3f::UnitZ()));
+        m_world_matrix.rotate(Eigen::AngleAxisf((float)m_rotation(1), Vec3f::UnitY()));
+        m_world_matrix.rotate(Eigen::AngleAxisf((float)m_rotation(0), Vec3f::UnitX()));
+#else
         m_world_matrix.rotate(Eigen::AngleAxisf((float)m_rotation, Vec3f::UnitZ()));
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
         m_world_matrix.scale((float)m_scaling_factor);
         m_world_matrix_dirty = false;
     }
@@ -403,7 +431,13 @@ void GLVolume::render() const
     ::glCullFace(GL_BACK);
     ::glPushMatrix();
     ::glTranslated(m_offset(0), m_offset(1), m_offset(2));
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    ::glRotated(m_rotation(2) * 180.0 / (double)PI, 0.0, 0.0, 1.0);
+    ::glRotated(m_rotation(1) * 180.0 / (double)PI, 0.0, 1.0, 0.0);
+    ::glRotated(m_rotation(0) * 180.0 / (double)PI, 1.0, 0.0, 0.0);
+#else
     ::glRotated(m_rotation * 180.0 / (double)PI, 0.0, 0.0, 1.0);
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
     ::glScaled(m_scaling_factor, m_scaling_factor, m_scaling_factor);
     if (this->indexed_vertex_array.indexed())
         this->indexed_vertex_array.render(this->tverts_range, this->qverts_range);
@@ -529,7 +563,13 @@ void GLVolume::render_VBOs(int color_id, int detection_id, int worldmatrix_id) c
 
     ::glPushMatrix();
     ::glTranslated(m_offset(0), m_offset(1), m_offset(2));
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    ::glRotated(m_rotation(2) * 180.0 / (double)PI, 0.0, 0.0, 1.0);
+    ::glRotated(m_rotation(1) * 180.0 / (double)PI, 0.0, 1.0, 0.0);
+    ::glRotated(m_rotation(0) * 180.0 / (double)PI, 1.0, 0.0, 0.0);
+#else
     ::glRotated(m_rotation * 180.0 / (double)PI, 0.0, 0.0, 1.0);
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
     ::glScaled(m_scaling_factor, m_scaling_factor, m_scaling_factor);
 
     if (n_triangles > 0)
@@ -574,7 +614,13 @@ void GLVolume::render_legacy() const
 
     ::glPushMatrix();
     ::glTranslated(m_offset(0), m_offset(1), m_offset(2));
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    ::glRotated(m_rotation(2) * 180.0 / (double)PI, 0.0, 0.0, 1.0);
+    ::glRotated(m_rotation(1) * 180.0 / (double)PI, 0.0, 1.0, 0.0);
+    ::glRotated(m_rotation(0) * 180.0 / (double)PI, 1.0, 0.0, 0.0);
+#else
     ::glRotated(m_rotation * 180.0 / (double)PI, 0.0, 0.0, 1.0);
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
     ::glScaled(m_scaling_factor, m_scaling_factor, m_scaling_factor);
 
     if (n_triangles > 0)
@@ -698,7 +744,11 @@ std::vector<int> GLVolumeCollection::load_object(
 #else
             v.set_offset(Vec3d(instance->offset(0), instance->offset(1), 0.0));
 #endif // ENABLE_MODELINSTANCE_3D_OFFSET
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+            v.set_rotation(instance->get_rotation());
+#else
             v.set_rotation(instance->rotation);
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
             v.set_scaling_factor(instance->scaling_factor);
         }
     }
@@ -2067,12 +2117,30 @@ void _3DScene::register_on_gizmo_scale_uniformly_callback(wxGLCanvas* canvas, vo
 
 void _3DScene::register_on_gizmo_rotate_callback(wxGLCanvas* canvas, void* callback)
 {
+#if !ENABLE_MODELINSTANCE_3D_ROTATION
     s_canvas_mgr.register_on_gizmo_rotate_callback(canvas, callback);
+#endif // !ENABLE_MODELINSTANCE_3D_ROTATION
+}
+
+void _3DScene::register_on_gizmo_rotate_3D_callback(wxGLCanvas* canvas, void* callback)
+{
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    s_canvas_mgr.register_on_gizmo_rotate_3D_callback(canvas, callback);
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 }
 
 void _3DScene::register_on_gizmo_flatten_callback(wxGLCanvas* canvas, void* callback)
 {
+#if !ENABLE_MODELINSTANCE_3D_ROTATION
     s_canvas_mgr.register_on_gizmo_flatten_callback(canvas, callback);
+#endif // !ENABLE_MODELINSTANCE_3D_ROTATION
+}
+
+void _3DScene::register_on_gizmo_flatten_3D_callback(wxGLCanvas* canvas, void* callback)
+{
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    s_canvas_mgr.register_on_gizmo_flatten_3D_callback(canvas, callback);
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 }
 
 void _3DScene::register_on_update_geometry_info_callback(wxGLCanvas* canvas, void* callback)

xs/src/slic3r/GUI/3DScene.hpp

@@ -256,8 +256,13 @@ public:
 private:
     // Offset of the volume to be rendered.
     Vec3d                 m_offset;
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    // Rotation around three axes of the volume to be rendered.
+    Vec3d                 m_rotation;
+#else
     // Rotation around Z axis of the volume to be rendered.
     double                m_rotation;
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
     // Scale factor of the volume to be rendered.
     double                m_scaling_factor;
     // World matrix of the volume to be rendered.
@@ -327,8 +332,13 @@ public:
     // Sets render color in dependence of current state
     void set_render_color();
 
-    double get_rotation();
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    const Vec3d& get_rotation() const;
+    void set_rotation(const Vec3d& rotation);
+#else
+    double get_rotation() const;
     void set_rotation(double rotation);
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 
     const Vec3d& get_offset() const;
     void set_offset(const Vec3d& offset);
@@ -558,7 +568,9 @@ public:
     static void register_on_enable_action_buttons_callback(wxGLCanvas* canvas, void* callback);
     static void register_on_gizmo_scale_uniformly_callback(wxGLCanvas* canvas, void* callback);
     static void register_on_gizmo_rotate_callback(wxGLCanvas* canvas, void* callback);
+    static void register_on_gizmo_rotate_3D_callback(wxGLCanvas* canvas, void* callback);
     static void register_on_gizmo_flatten_callback(wxGLCanvas* canvas, void* callback);
+    static void register_on_gizmo_flatten_3D_callback(wxGLCanvas* canvas, void* callback);
     static void register_on_update_geometry_info_callback(wxGLCanvas* canvas, void* callback);
 
     static void register_action_add_callback(wxGLCanvas* canvas, void* callback);

xs/src/slic3r/GUI/GLCanvas3D.cpp

@@ -1184,9 +1184,11 @@ bool GLCanvas3D::Gizmos::init(GLCanvas3D& parent)
         return false;
     }
 
+#if !ENABLE_MODELINSTANCE_3D_ROTATION
     // temporary disable x and y grabbers
     gizmo->disable_grabber(0);
     gizmo->disable_grabber(1);
+#endif // !ENABLE_MODELINSTANCE_3D_ROTATION
 
     m_gizmos.insert(GizmosMap::value_type(Rotate, gizmo));
 
@@ -1436,6 +1438,35 @@ void GLCanvas3D::Gizmos::set_scale(float scale)
         reinterpret_cast<GLGizmoScale3D*>(it->second)->set_scale(scale);
 }
 
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+Vec3d GLCanvas3D::Gizmos::get_rotation() const
+{
+    if (!m_enabled)
+        return Vec3d::Zero();
+
+    GizmosMap::const_iterator it = m_gizmos.find(Rotate);
+    return (it != m_gizmos.end()) ? reinterpret_cast<GLGizmoRotate3D*>(it->second)->get_rotation() : Vec3d::Zero();
+}
+
+void GLCanvas3D::Gizmos::set_rotation(const Vec3d& rotation)
+{
+    if (!m_enabled)
+        return;
+
+    GizmosMap::const_iterator it = m_gizmos.find(Rotate);
+    if (it != m_gizmos.end())
+        reinterpret_cast<GLGizmoRotate3D*>(it->second)->set_rotation(rotation);
+}
+
+Vec3d GLCanvas3D::Gizmos::get_flattening_rotation() const
+{
+    if (!m_enabled)
+        return Vec3d::Zero();
+
+    GizmosMap::const_iterator it = m_gizmos.find(Flatten);
+    return (it != m_gizmos.end()) ? reinterpret_cast<GLGizmoFlatten*>(it->second)->get_flattening_rotation() : Vec3d::Zero();
+}
+#else
 float GLCanvas3D::Gizmos::get_angle_z() const
 {
     if (!m_enabled)
@@ -1463,6 +1494,7 @@ Vec3d GLCanvas3D::Gizmos::get_flattening_normal() const
     GizmosMap::const_iterator it = m_gizmos.find(Flatten);
     return (it != m_gizmos.end()) ? reinterpret_cast<GLGizmoFlatten*>(it->second)->get_flattening_normal() : Vec3d::Zero();
 }
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 
 void GLCanvas3D::Gizmos::set_flattening_data(const ModelObject* model_object)
 {
@@ -2400,7 +2432,11 @@ void GLCanvas3D::update_gizmos_data()
                 m_gizmos.set_position(Vec3d(model_instance->offset(0), model_instance->offset(1), 0.0));
 #endif // ENABLE_MODELINSTANCE_3D_OFFSET
                 m_gizmos.set_scale(model_instance->scaling_factor);
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+                m_gizmos.set_rotation(model_instance->get_rotation());
+#else
                 m_gizmos.set_angle_z(model_instance->rotation);
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
                 m_gizmos.set_flattening_data(model_object);
             }
         }
@@ -2409,7 +2445,11 @@ void GLCanvas3D::update_gizmos_data()
     {
         m_gizmos.set_position(Vec3d::Zero());
         m_gizmos.set_scale(1.0f);
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+        m_gizmos.set_rotation(Vec3d::Zero());
+#else
         m_gizmos.set_angle_z(0.0f);
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
         m_gizmos.set_flattening_data(nullptr);
     }
 }
@@ -2772,6 +2812,19 @@ void GLCanvas3D::register_on_gizmo_scale_uniformly_callback(void* callback)
         m_on_gizmo_scale_uniformly_callback.register_callback(callback);
 }
 
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+void GLCanvas3D::register_on_gizmo_rotate_3D_callback(void* callback)
+{
+    if (callback != nullptr)
+        m_on_gizmo_rotate_3D_callback.register_callback(callback);
+}
+
+void GLCanvas3D::register_on_gizmo_flatten_3D_callback(void* callback)
+{
+    if (callback != nullptr)
+        m_on_gizmo_flatten_3D_callback.register_callback(callback);
+}
+#else
 void GLCanvas3D::register_on_gizmo_rotate_callback(void* callback)
 {
     if (callback != nullptr)
@@ -2783,6 +2836,7 @@ void GLCanvas3D::register_on_gizmo_flatten_callback(void* callback)
     if (callback != nullptr)
         m_on_gizmo_flatten_callback.register_callback(callback);
 }
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 
 void GLCanvas3D::register_on_update_geometry_info_callback(void* callback)
 {
@@ -3133,6 +3187,11 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
             m_mouse.drag.gizmo_volume_idx = _get_first_selected_volume_id(selected_object_idx);
 
             if (m_gizmos.get_current_type() == Gizmos::Flatten) {
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+                // Rotate the object so the normal points downward:
+                const Vec3d& rotation = m_gizmos.get_flattening_rotation();
+                m_on_gizmo_flatten_3D_callback.call(rotation(0), rotation(1), rotation(2));
+#else
                 // Rotate the object so the normal points downward:
                 Vec3d normal = m_gizmos.get_flattening_normal();
                 if (normal(0) != 0.0 || normal(1) != 0.0 || normal(2) != 0.0) {
@@ -3140,6 +3199,7 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
                     float angle = acos(clamp(-1.0, 1.0, -normal(2)));
                     m_on_gizmo_flatten_callback.call(angle, (float)axis(0), (float)axis(1), (float)axis(2));
                 }
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
             }
 
             m_dirty = true;
@@ -3322,6 +3382,15 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
         }
         case Gizmos::Rotate:
         {
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+            // Apply new temporary rotation
+            Vec3d rotation = m_gizmos.get_rotation();
+            for (GLVolume* v : volumes)
+            {
+                v->set_rotation(rotation);
+            }
+            update_rotation_value(rotation);
+#else
             // Apply new temporary angle_z
             float angle_z = m_gizmos.get_angle_z();
             for (GLVolume* v : volumes)
@@ -3329,6 +3398,7 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
                 v->set_rotation((double)angle_z);
             }
             update_rotation_value((double)angle_z, Z);
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
             break;
         }
         default:
@@ -3474,14 +3544,19 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
             }
             case Gizmos::Rotate:
             {
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+                const Vec3d& rotation = m_gizmos.get_rotation();
+                m_on_gizmo_rotate_3D_callback.call(rotation(0), rotation(1), rotation(2));
+#else
                 m_on_gizmo_rotate_callback.call((double)m_gizmos.get_angle_z());
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
                 break;
             }
             default:
                 break;
             }
             m_gizmos.stop_dragging();
-            Slic3r::GUI::update_settings_value();
+            update_settings_value();
         }
 
         m_mouse.drag.move_volume_idx = -1;
@@ -3921,8 +3996,13 @@ void GLCanvas3D::_deregister_callbacks()
     m_on_wipe_tower_moved_callback.deregister_callback();
     m_on_enable_action_buttons_callback.deregister_callback();
     m_on_gizmo_scale_uniformly_callback.deregister_callback();
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    m_on_gizmo_rotate_3D_callback.deregister_callback();
+    m_on_gizmo_flatten_3D_callback.deregister_callback();
+#else
     m_on_gizmo_rotate_callback.deregister_callback();
     m_on_gizmo_flatten_callback.deregister_callback();
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
     m_on_update_geometry_info_callback.deregister_callback();
 
     m_action_add_callback.deregister_callback();

xs/src/slic3r/GUI/GLCanvas3D.hpp

@@ -387,11 +387,20 @@ class GLCanvas3D
         float get_scale() const;
         void set_scale(float scale);
 
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+        Vec3d get_rotation() const;
+        void set_rotation(const Vec3d& rotation);
+#else
         float get_angle_z() const;
         void set_angle_z(float angle_z);
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 
-        void set_flattening_data(const ModelObject* model_object);
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+        Vec3d get_flattening_rotation() const;
+#else
         Vec3d get_flattening_normal() const;
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
+        void set_flattening_data(const ModelObject* model_object);
 
         void render_current_gizmo(const BoundingBoxf3& box) const;
 
@@ -507,8 +516,13 @@ class GLCanvas3D
     PerlCallback m_on_wipe_tower_moved_callback;
     PerlCallback m_on_enable_action_buttons_callback;
     PerlCallback m_on_gizmo_scale_uniformly_callback;
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    PerlCallback m_on_gizmo_rotate_3D_callback;
+    PerlCallback m_on_gizmo_flatten_3D_callback;
+#else
     PerlCallback m_on_gizmo_rotate_callback;
     PerlCallback m_on_gizmo_flatten_callback;
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
     PerlCallback m_on_update_geometry_info_callback;
 
     PerlCallback m_action_add_callback;
@@ -632,8 +646,13 @@ public:
     void register_on_wipe_tower_moved_callback(void* callback);
     void register_on_enable_action_buttons_callback(void* callback);
     void register_on_gizmo_scale_uniformly_callback(void* callback);
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    void register_on_gizmo_rotate_3D_callback(void* callback);
+    void register_on_gizmo_flatten_3D_callback(void* callback);
+#else
     void register_on_gizmo_rotate_callback(void* callback);
     void register_on_gizmo_flatten_callback(void* callback);
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
     void register_on_update_geometry_info_callback(void* callback);
 
     void register_action_add_callback(void* callback);

xs/src/slic3r/GUI/GLCanvas3DManager.cpp

@@ -699,6 +699,21 @@ void GLCanvas3DManager::register_on_gizmo_scale_uniformly_callback(wxGLCanvas* c
         it->second->register_on_gizmo_scale_uniformly_callback(callback);
 }
 
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+void GLCanvas3DManager::register_on_gizmo_rotate_3D_callback(wxGLCanvas* canvas, void* callback)
+{
+    CanvasesMap::iterator it = _get_canvas(canvas);
+    if (it != m_canvases.end())
+        it->second->register_on_gizmo_rotate_3D_callback(callback);
+}
+
+void GLCanvas3DManager::register_on_gizmo_flatten_3D_callback(wxGLCanvas* canvas, void* callback)
+{
+    CanvasesMap::iterator it = _get_canvas(canvas);
+    if (it != m_canvases.end())
+        it->second->register_on_gizmo_flatten_3D_callback(callback);
+}
+#else
 void GLCanvas3DManager::register_on_gizmo_rotate_callback(wxGLCanvas* canvas, void* callback)
 {
     CanvasesMap::iterator it = _get_canvas(canvas);
@@ -712,6 +727,7 @@ void GLCanvas3DManager::register_on_gizmo_flatten_callback(wxGLCanvas* canvas, v
     if (it != m_canvases.end())
         it->second->register_on_gizmo_flatten_callback(callback);
 }
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 
 void GLCanvas3DManager::register_on_update_geometry_info_callback(wxGLCanvas* canvas, void* callback)
 {

xs/src/slic3r/GUI/GLCanvas3DManager.hpp

@@ -163,8 +163,13 @@ public:
     void register_on_wipe_tower_moved_callback(wxGLCanvas* canvas, void* callback);
     void register_on_enable_action_buttons_callback(wxGLCanvas* canvas, void* callback);
     void register_on_gizmo_scale_uniformly_callback(wxGLCanvas* canvas, void* callback);
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    void register_on_gizmo_rotate_3D_callback(wxGLCanvas* canvas, void* callback);
+    void register_on_gizmo_flatten_3D_callback(wxGLCanvas* canvas, void* callback);
+#else
     void register_on_gizmo_rotate_callback(wxGLCanvas* canvas, void* callback);
     void register_on_gizmo_flatten_callback(wxGLCanvas* canvas, void* callback);
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
     void register_on_update_geometry_info_callback(wxGLCanvas* canvas, void* callback);
 
     void register_action_add_callback(wxGLCanvas* canvas, void* callback);

xs/src/slic3r/GUI/GLGizmo.cpp

@@ -1251,15 +1251,28 @@ void GLGizmoFlatten::on_render(const BoundingBoxf3& box) const
             ::glColor4f(0.9f, 0.9f, 0.9f, 0.5f);
 
 #if ENABLE_MODELINSTANCE_3D_OFFSET
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+        for (const InstanceData& inst : m_instances) {
+            Vec3d position = inst.position + dragged_offset;
+#else
         for (Vec3d offset : m_instances_positions) {
             offset += dragged_offset;
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 #else
         for (Vec2d offset : m_instances_positions) {
             offset += to_2d(dragged_offset);
 #endif // ENABLE_MODELINSTANCE_3D_OFFSET
             ::glPushMatrix();
 #if ENABLE_MODELINSTANCE_3D_OFFSET
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+            ::glTranslated(position(0), position(1), position(2));
+            ::glRotated(inst.rotation(2) * 180.0 / (double)PI, 0.0, 0.0, 1.0);
+            ::glRotated(inst.rotation(1) * 180.0 / (double)PI, 0.0, 1.0, 0.0);
+            ::glRotated(inst.rotation(0) * 180.0 / (double)PI, 1.0, 0.0, 0.0);
+            ::glScaled(inst.scaling_factor, inst.scaling_factor, inst.scaling_factor);
+#else
             ::glTranslated(offset(0), offset(1), offset(2));
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 #else
             ::glTranslatef((GLfloat)offset(0), (GLfloat)offset(1), 0.0f);
 #endif // ENABLE_MODELINSTANCE_3D_OFFSET
@@ -1282,13 +1295,25 @@ void GLGizmoFlatten::on_render_for_picking(const BoundingBoxf3& box) const
     {
         ::glColor3f(1.0f, 1.0f, picking_color_component(i));
 #if ENABLE_MODELINSTANCE_3D_OFFSET
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+        for (const InstanceData& inst : m_instances) {
+#else
         for (const Vec3d& offset : m_instances_positions) {
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 #else
         for (const Vec2d& offset : m_instances_positions) {
 #endif // ENABLE_MODELINSTANCE_3D_OFFSET
             ::glPushMatrix();
 #if ENABLE_MODELINSTANCE_3D_OFFSET
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+            ::glTranslated(inst.position(0), inst.position(1), inst.position(2));
+            ::glRotated(inst.rotation(2) * 180.0 / (double)PI, 0.0, 0.0, 1.0);
+            ::glRotated(inst.rotation(1) * 180.0 / (double)PI, 0.0, 1.0, 0.0);
+            ::glRotated(inst.rotation(0) * 180.0 / (double)PI, 1.0, 0.0, 0.0);
+            ::glScaled(inst.scaling_factor, inst.scaling_factor, inst.scaling_factor);
+#else
             ::glTranslated(offset(0), offset(1), offset(2));
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 #else
             ::glTranslatef((GLfloat)offset(0), (GLfloat)offset(1), 0.0f);
 #endif // ENABLE_MODELINSTANCE_3D_OFFSET
@@ -1307,10 +1332,18 @@ void GLGizmoFlatten::set_flattening_data(const ModelObject* model_object)
 
     // ...and save the updated positions of the object instances:
     if (m_model_object && !m_model_object->instances.empty()) {
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+        m_instances.clear();
+#else
         m_instances_positions.clear();
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
         for (const auto* instance : m_model_object->instances)
 #if ENABLE_MODELINSTANCE_3D_OFFSET
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+            m_instances.emplace_back(instance->get_offset(), instance->get_rotation(), instance->scaling_factor);
+#else
             m_instances_positions.emplace_back(instance->get_offset());
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 #else
             m_instances_positions.emplace_back(instance->offset);
 #endif // ENABLE_MODELINSTANCE_3D_OFFSET
@@ -1326,8 +1359,10 @@ void GLGizmoFlatten::update_planes()
     for (const ModelVolume* vol : m_model_object->volumes)
         ch.merge(vol->get_convex_hull());
     ch = ch.convex_hull_3d();
+#if !ENABLE_MODELINSTANCE_3D_ROTATION
     ch.scale(m_model_object->instances.front()->scaling_factor);
     ch.rotate_z(m_model_object->instances.front()->rotation);
+#endif // !ENABLE_MODELINSTANCE_3D_ROTATION
 
     m_planes.clear();
 
@@ -1372,8 +1407,8 @@ void GLGizmoFlatten::update_planes()
         // if this is a just a very small triangle, remove it to speed up further calculations (it would be rejected anyway):
         if (m_planes.back().vertices.size() == 3 &&
                (m_planes.back().vertices[0] - m_planes.back().vertices[1]).norm() < 1.f
-            || (m_planes.back().vertices[0] - m_planes.back().vertices[2]).norm() < 1.f)
+               || (m_planes.back().vertices[0] - m_planes.back().vertices[2]).norm() < 1.f)
-            m_planes.pop_back();
+               m_planes.pop_back();
     }
 
     // Now we'll go through all the polygons, transform the points into xy plane to process them:
@@ -1476,8 +1511,10 @@ void GLGizmoFlatten::update_planes()
     m_source_data.bounding_boxes.clear();
     for (const auto& vol : m_model_object->volumes)
         m_source_data.bounding_boxes.push_back(vol->get_convex_hull().bounding_box());
+#if !ENABLE_MODELINSTANCE_3D_ROTATION
     m_source_data.scaling_factor = m_model_object->instances.front()->scaling_factor;
     m_source_data.rotation = m_model_object->instances.front()->rotation;
+#endif // !ENABLE_MODELINSTANCE_3D_ROTATION
     const float* first_vertex = m_model_object->volumes.front()->get_convex_hull().first_vertex();
     m_source_data.mesh_first_point = Vec3d((double)first_vertex[0], (double)first_vertex[1], (double)first_vertex[2]);
 }
@@ -1489,10 +1526,14 @@ bool GLGizmoFlatten::is_plane_update_necessary() const
     if (m_state != On || !m_model_object || m_model_object->instances.empty())
         return false;
 
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    if (m_model_object->volumes.size() != m_source_data.bounding_boxes.size())
+#else
     if (m_model_object->volumes.size() != m_source_data.bounding_boxes.size()
      || m_model_object->instances.front()->scaling_factor != m_source_data.scaling_factor
      || m_model_object->instances.front()->rotation != m_source_data.rotation)
-         return true;
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
+        return true;
 
     // now compare the bounding boxes:
     for (unsigned int i=0; i<m_model_object->volumes.size(); ++i)
@@ -1507,11 +1548,22 @@ bool GLGizmoFlatten::is_plane_update_necessary() const
     return false;
 }
 
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+Vec3d GLGizmoFlatten::get_flattening_rotation() const
+{
+    // calculates the rotations in model space
+    Eigen::Quaterniond q;
+    Vec3d angles = q.setFromTwoVectors(m_normal, -Vec3d::UnitZ()).toRotationMatrix().eulerAngles(2, 1, 0);
+    m_normal = Vec3d::Zero();
+    return Vec3d(angles(2), angles(1), angles(0));
+}
+#else
 Vec3d GLGizmoFlatten::get_flattening_normal() const {
     Vec3d normal = m_model_object->instances.front()->world_matrix(true).matrix().block(0, 0, 3, 3).inverse() * m_normal;
     m_normal = Vec3d::Zero();
     return normal.normalized();
 }
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 
 } // namespace GUI
 } // namespace Slic3r

xs/src/slic3r/GUI/GLGizmo.hpp

@@ -188,6 +188,10 @@ class GLGizmoRotate3D : public GLGizmoBase
 public:
     explicit GLGizmoRotate3D(GLCanvas3D& parent);
 
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    Vec3d get_rotation() const { return Vec3d(m_gizmos[X].get_angle(), m_gizmos[Y].get_angle(), m_gizmos[Z].get_angle()); }
+    void set_rotation(const Vec3d& rotation) { m_gizmos[X].set_angle(rotation(0)); m_gizmos[Y].set_angle(rotation(1)); m_gizmos[Z].set_angle(rotation(2)); }
+#else
     double get_angle_x() const { return m_gizmos[X].get_angle(); }
     void set_angle_x(double angle) { m_gizmos[X].set_angle(angle); }
 
@@ -196,6 +200,7 @@ public:
 
     double get_angle_z() const { return m_gizmos[Z].get_angle(); }
     void set_angle_z(double angle) { m_gizmos[Z].set_angle(angle); }
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 
 protected:
     virtual bool on_init();
@@ -340,8 +345,10 @@ private:
     };
     struct SourceDataSummary {
         std::vector<BoundingBoxf3> bounding_boxes; // bounding boxes of convex hulls of individual volumes
+#if !ENABLE_MODELINSTANCE_3D_ROTATION
         float scaling_factor;
         float rotation;
+#endif // !ENABLE_MODELINSTANCE_3D_ROTATION
         Vec3d mesh_first_point;
     };
 
@@ -350,7 +357,19 @@ private:
 
     std::vector<PlaneData> m_planes;
 #if ENABLE_MODELINSTANCE_3D_OFFSET
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    struct InstanceData
+    {
+        Vec3d position;
+        Vec3d rotation; 
+        double scaling_factor;
+
+        InstanceData(const Vec3d& position, const Vec3d& rotation, double scaling_factor) : position(position), rotation(rotation), scaling_factor(scaling_factor) {}
+    };
+    std::vector<InstanceData> m_instances;
+#else
     Pointf3s m_instances_positions;
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 #else
     std::vector<Vec2d> m_instances_positions;
 #endif // ENABLE_MODELINSTANCE_3D_OFFSET
@@ -364,7 +383,11 @@ public:
     explicit GLGizmoFlatten(GLCanvas3D& parent);
 
     void set_flattening_data(const ModelObject* model_object);
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    Vec3d get_flattening_rotation() const;
+#else
     Vec3d get_flattening_normal() const;
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 
 protected:
     virtual bool on_init();

xs/src/slic3r/GUI/GUI_ObjectParts.cpp

@@ -1802,11 +1802,15 @@ void update_scale_values(double scaling_factor)
 
 void update_rotation_values()
 {
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    update_rotation_value((*m_objects)[m_selected_object_id]->instances.front()->get_rotation());
+#else
     auto og = get_optgroup(ogFrequentlyObjectSettings);
     auto instance = (*m_objects)[m_selected_object_id]->instances.front();
     og->set_value("rotation_x", 0);
     og->set_value("rotation_y", 0);
     og->set_value("rotation_z", int(Geometry::rad2deg(instance->rotation)));
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 }
 
 void update_rotation_value(double angle, Axis axis)
@@ -1836,6 +1840,16 @@ void update_rotation_value(double angle, Axis axis)
     og->set_value(axis_str, int(Geometry::rad2deg(angle)));
 }
 
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+void update_rotation_value(const Vec3d& rotation)
+{
+    auto og = get_optgroup(ogFrequentlyObjectSettings);
+    og->set_value("rotation_x", int(Geometry::rad2deg(rotation(0))));
+    og->set_value("rotation_y", int(Geometry::rad2deg(rotation(1))));
+    og->set_value("rotation_z", int(Geometry::rad2deg(rotation(2))));
+}
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
+
 void set_uniform_scaling(const bool uniform_scale)
 {
     g_is_uniform_scale = uniform_scale;

xs/src/slic3r/GUI/GUI_ObjectParts.hpp

@@ -124,6 +124,9 @@ void update_scale_values(double scaling_factor);
 void update_rotation_values();
 // update rotation value after "gizmos"
 void update_rotation_value(double angle, Axis axis);
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+void update_rotation_value(const Vec3d& rotation);
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
 void set_uniform_scaling(const bool uniform_scale);
 
 void on_begin_drag(wxDataViewEvent &event);

xs/xsp/GUI_3DScene.xsp

@@ -651,6 +651,13 @@ register_on_gizmo_rotate_callback(canvas, callback)
     CODE:
         _3DScene::register_on_gizmo_rotate_callback((wxGLCanvas*)wxPli_sv_2_object(aTHX_ canvas, "Wx::GLCanvas"), (void*)callback);
 
+void
+register_on_gizmo_rotate_3D_callback(canvas, callback)
+        SV *canvas;
+        SV *callback;
+    CODE:
+        _3DScene::register_on_gizmo_rotate_3D_callback((wxGLCanvas*)wxPli_sv_2_object(aTHX_ canvas, "Wx::GLCanvas"), (void*)callback);
+
 void
 register_on_gizmo_flatten_callback(canvas, callback)
         SV *canvas;
@@ -658,6 +665,13 @@ register_on_gizmo_flatten_callback(canvas, callback)
     CODE:
         _3DScene::register_on_gizmo_flatten_callback((wxGLCanvas*)wxPli_sv_2_object(aTHX_ canvas, "Wx::GLCanvas"), (void*)callback);
 
+void
+register_on_gizmo_flatten_3D_callback(canvas, callback)
+        SV *canvas;
+        SV *callback;
+    CODE:
+        _3DScene::register_on_gizmo_flatten_3D_callback((wxGLCanvas*)wxPli_sv_2_object(aTHX_ canvas, "Wx::GLCanvas"), (void*)callback);
+
 void
 register_on_update_geometry_info_callback(canvas, callback)
         SV *canvas;

xs/xsp/Model.xsp

@@ -364,8 +364,13 @@ ModelMaterial::attributes()
     Ref<ModelObject> object()
         %code%{ RETVAL = THIS->get_object(); %};
 
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    double rotation()
+        %code%{ RETVAL = THIS->get_rotation(Z); %};
+#else
     double rotation()
         %code%{ RETVAL = THIS->rotation; %};
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
     double scaling_factor()
         %code%{ RETVAL = THIS->scaling_factor; %};
 #if ENABLE_MODELINSTANCE_3D_OFFSET
@@ -376,8 +381,17 @@ ModelMaterial::attributes()
         %code%{ RETVAL = &THIS->offset; %};
 #endif // ENABLE_MODELINSTANCE_3D_OFFSET
 
+#if ENABLE_MODELINSTANCE_3D_ROTATION
+    void set_rotation(double val)
+        %code%{ THIS->set_rotation(Z, val); THIS->get_object()->invalidate_bounding_box(); %};
+        
+    void set_rotations(Vec3d *rotation)
+        %code%{ THIS->set_rotation(*rotation); THIS->get_object()->invalidate_bounding_box(); %};
+        
+#else
     void set_rotation(double val)
         %code%{ THIS->rotation = val; THIS->get_object()->invalidate_bounding_box(); %};
+#endif // ENABLE_MODELINSTANCE_3D_ROTATION
     void set_scaling_factor(double val)
         %code%{ THIS->scaling_factor = val; THIS->get_object()->invalidate_bounding_box(); %};
 #if ENABLE_MODELINSTANCE_3D_OFFSET