Do not allow objects to be placed fully below bed

src/libslic3r/Model.hpp

@@ -1177,6 +1177,7 @@ void check_model_ids_equal(const Model &model1, const Model &model2);
 #endif /* NDEBUG */
 
 static const float SINKING_Z_THRESHOLD = -0.001f;
+static const double SINKING_MIN_Z_THRESHOLD = 0.05;
 
 } // namespace Slic3r
 

src/slic3r/GUI/3DScene.cpp

@@ -595,7 +595,7 @@ bool GLVolume::is_sinking() const
 
 bool GLVolume::is_below_printbed() const
 {
-    return transformed_convex_hull_bounding_box().max(2) < 0.0;
+    return transformed_convex_hull_bounding_box().max.z() < 0.0;
 }
 
 #if ENABLE_SINKING_CONTOURS

src/slic3r/GUI/MainFrame.cpp

@@ -621,7 +621,7 @@ void MainFrame::update_title()
         if (!dirty_marker.empty() || !project.empty()) {
             if (!dirty_marker.empty() && project.empty())
                 project = _("Untitled");
-                title = dirty_marker + project + " - ";
+            title = dirty_marker + project + " - ";
         }
     }
 

src/slic3r/GUI/Selection.cpp

@@ -683,7 +683,8 @@ void Selection::translate(const Vec3d& displacement, bool local)
         synchronize_unselected_volumes();
 #endif // !DISABLE_INSTANCES_SYNCH
 
-    this->set_bounding_boxes_dirty();
+    ensure_not_below_bed();
+    set_bounding_boxes_dirty();
 }
 
 // Rotate an object around one of the axes. Only one rotation component is expected to be changing.
@@ -1712,7 +1713,7 @@ void Selection::calc_unscaled_instance_bounding_box() const
             if (volume.is_modifier)
                 continue;
             Transform3d trafo = volume.get_instance_transformation().get_matrix(false, false, true, false) * volume.get_volume_transformation().get_matrix();
-            trafo.translation()(2) += volume.get_sla_shift_z();
+            trafo.translation().z() += volume.get_sla_shift_z();
             unscaled_instance_bounding_box->merge(volume.transformed_convex_hull_bounding_box(trafo));
         }
     }
@@ -1729,7 +1730,7 @@ void Selection::calc_scaled_instance_bounding_box() const
             if (volume.is_modifier)
                 continue;
             Transform3d trafo = volume.get_instance_transformation().get_matrix(false, false, false, false) * volume.get_volume_transformation().get_matrix();
-            trafo.translation()(2) += volume.get_sla_shift_z();
+            trafo.translation().z() += volume.get_sla_shift_z();
             scaled_instance_bounding_box->merge(volume.transformed_convex_hull_bounding_box(trafo));
         }
     }
@@ -2134,6 +2135,32 @@ void Selection::ensure_on_bed()
     }
 }
 
+void Selection::ensure_not_below_bed()
+{
+    typedef std::map<std::pair<int, int>, double> InstancesToZMap;
+    InstancesToZMap instances_max_z;
+
+    for (size_t i = 0; i < m_volumes->size(); ++i) {
+        GLVolume* volume = (*m_volumes)[i];
+        if (!volume->is_wipe_tower && !volume->is_modifier) {
+            const double max_z = volume->transformed_convex_hull_bounding_box().max.z();
+            std::pair<int, int> instance = std::make_pair(volume->object_idx(), volume->instance_idx());
+            InstancesToZMap::iterator it = instances_max_z.find(instance);
+            if (it == instances_max_z.end())
+                it = instances_max_z.insert(InstancesToZMap::value_type(instance, -DBL_MAX)).first;
+
+            it->second = std::max(it->second, max_z);
+        }
+    }
+
+    for (GLVolume* volume : *m_volumes) {
+        std::pair<int, int> instance = std::make_pair(volume->object_idx(), volume->instance_idx());
+        InstancesToZMap::iterator it = instances_max_z.find(instance);
+        if (it != instances_max_z.end() && it->second < SINKING_MIN_Z_THRESHOLD)
+            volume->set_instance_offset(Z, volume->get_instance_offset(Z) + SINKING_MIN_Z_THRESHOLD - it->second);
+    }
+}
+
 bool Selection::is_from_fully_selected_instance(unsigned int volume_idx) const
 {
     struct SameInstance

src/slic3r/GUI/Selection.hpp

@@ -385,6 +385,7 @@ public:
 
 private:
     void ensure_on_bed();
+    void ensure_not_below_bed();
     bool is_from_fully_selected_instance(unsigned int volume_idx) const;
 
     void paste_volumes_from_clipboard();