diff --git a/src/libslic3r/PrintObject.cpp b/src/libslic3r/PrintObject.cpp
index 273fc9c10..c90a05ef3 100644
--- a/src/libslic3r/PrintObject.cpp
+++ b/src/libslic3r/PrintObject.cpp
@@ -2733,7 +2733,7 @@ void PrintObject::project_and_append_custom_supports(
             std::array<Vec2f, 3> trianglef;
             for (int i=0; i<3; ++i) {
                 trianglef[i] = Vec2f(facet[i].x(), facet[i].y());
-                trianglef[i] += Vec2f(unscale<float>(this->center_offset().x()),
+                trianglef[i] -= Vec2f(unscale<float>(this->center_offset().x()),
                                       unscale<float>(this->center_offset().y()));
             }
 
@@ -2823,8 +2823,9 @@ void PrintObject::project_and_append_custom_supports(
         // Now append the collected polygons to respective layers.
         for (auto& trg : projections_of_triangles) {
             int layer_id = trg.first_layer_id;
-
             for (const LightPolygon& poly : trg.polygons) {
+                if (layer_id >= int(expolys.size()))
+                    break; // part of triangle could be projected above top layer
                 expolys[layer_id].emplace_back(std::move(poly.pts));
                 ++layer_id;
             }
diff --git a/src/libslic3r/SupportMaterial.cpp b/src/libslic3r/SupportMaterial.cpp
index 43f582d5f..95b4c334b 100644
--- a/src/libslic3r/SupportMaterial.cpp
+++ b/src/libslic3r/SupportMaterial.cpp
@@ -409,7 +409,7 @@ void PrintObjectSupportMaterial::generate(PrintObject &object)
                 export_print_z_polygons_and_extrusions_to_svg(
                     debug_out_path("support-w-fills-%d-%lf.svg", iRun, layers_sorted[i]->print_z).c_str(),
                     layers_sorted.data() + i, j - i,
-                    *object.support_layers[layer_id]);
+                    *object.support_layers()[layer_id]);
                 ++layer_id;
             }
             i = j;
@@ -597,8 +597,8 @@ public:
             ::fwrite(&n_points, 4, 1, file);
             for (uint32_t j = 0; j < n_points; ++ j) {
                 const Point &pt = poly.points[j];
-                ::fwrite(&pt.x, sizeof(coord_t), 1, file);
-                ::fwrite(&pt.y, sizeof(coord_t), 1, file);
+                ::fwrite(&pt.x(), sizeof(coord_t), 1, file);
+                ::fwrite(&pt.y(), sizeof(coord_t), 1, file);
             }
         }
         n_polygons = m_trimming_polygons->size();
@@ -609,8 +609,8 @@ public:
             ::fwrite(&n_points, 4, 1, file);
             for (uint32_t j = 0; j < n_points; ++ j) {
                 const Point &pt = poly.points[j];
-                ::fwrite(&pt.x, sizeof(coord_t), 1, file);
-                ::fwrite(&pt.y, sizeof(coord_t), 1, file);
+                ::fwrite(&pt.x(), sizeof(coord_t), 1, file);
+                ::fwrite(&pt.y(), sizeof(coord_t), 1, file);
             }
         }
         ::fclose(file);
@@ -1134,7 +1134,7 @@ PrintObjectSupportMaterial::MyLayersPtr PrintObjectSupportMaterial::top_contact_
                         {
                             ::Slic3r::SVG svg(debug_out_path("support-top-contacts-raw-run%d-layer%d-region%d.svg", 
                                 iRun, layer_id, 
-                                std::find_if(layer.regions.begin(), layer.regions.end(), [layerm](const LayerRegion* other){return other == layerm;}) - layer.regions.begin()),
+                                std::find_if(layer.regions().begin(), layer.regions().end(), [layerm](const LayerRegion* other){return other == layerm;}) - layer.regions().begin()),
                             get_extents(diff_polygons));
                             Slic3r::ExPolygons expolys = union_ex(diff_polygons, false);
                             svg.draw(expolys);
@@ -1152,7 +1152,7 @@ PrintObjectSupportMaterial::MyLayersPtr PrintObjectSupportMaterial::top_contact_
                         Slic3r::SVG::export_expolygons(
                             debug_out_path("support-top-contacts-filtered-run%d-layer%d-region%d-z%f.svg", 
                                 iRun, layer_id, 
-                                std::find_if(layer.regions.begin(), layer.regions.end(), [layerm](const LayerRegion* other){return other == layerm;}) - layer.regions.begin(), 
+                                std::find_if(layer.regions().begin(), layer.regions().end(), [layerm](const LayerRegion* other){return other == layerm;}) - layer.regions().begin(),
                                 layer.print_z),
                             union_ex(diff_polygons, false));
                         #endif /* SLIC3R_DEBUG */
@@ -1482,7 +1482,7 @@ PrintObjectSupportMaterial::MyLayersPtr PrintObjectSupportMaterial::bottom_conta
                         svg.draw(union_ex(top, false), "blue", 0.5f);
                         svg.draw(union_ex(projection_raw, true), "red", 0.5f);
                         svg.draw_outline(union_ex(projection_raw, true), "red", "blue", scale_(0.1f));
-                        svg.draw(layer.slices, "green", 0.5f);
+                        svg.draw(layer.lslices, "green", 0.5f);
                     }
         #endif /* SLIC3R_DEBUG */
 
diff --git a/src/libslic3r/TriangleSelector.cpp b/src/libslic3r/TriangleSelector.cpp
index 763bf5861..9555c42a6 100644
--- a/src/libslic3r/TriangleSelector.cpp
+++ b/src/libslic3r/TriangleSelector.cpp
@@ -60,8 +60,9 @@ void TriangleSelector::select_patch(const Vec3f& hit, int facet_start,
             if (select_triangle(facet, new_state)) {
                 // add neighboring facets to list to be proccessed later
                 for (int n=0; n<3; ++n) {
-                    if (faces_camera(m_mesh->stl.neighbors_start[facet].neighbor[n]))
-                        facets_to_check.push_back(m_mesh->stl.neighbors_start[facet].neighbor[n]);
+                    int neighbor_idx = m_mesh->stl.neighbors_start[facet].neighbor[n];
+                    if (neighbor_idx >=0 && faces_camera(neighbor_idx))
+                        facets_to_check.push_back(neighbor_idx);
                 }
             }
         }