Don't attempt to convert reference image to a SHAPE_POLY_SET.

Also make sure we render table thicknesses when they're
drawn on copper layers.

3d-viewer/3d_canvas/create_layer_items.cpp

@@ -640,6 +640,9 @@ void BOARD_ADAPTER::createLayers( REPORTER* aStatusReporter )
                 addShape( static_cast<PCB_DIMENSION_BASE*>( item ), layerContainer, item );
                 break;
 
+            case PCB_REFERENCE_IMAGE_T:     // ignore
+                break;
+
             default:
                 wxLogTrace( m_logTrace, wxT( "createLayers: item type: %d not implemented" ), item->Type() );
                 break;
@@ -666,7 +669,7 @@ void BOARD_ADAPTER::createLayers( REPORTER* aStatusReporter )
                     PCB_TEXT* text = static_cast<PCB_TEXT*>( item );
                     text->TransformTextToPolySet( *copperPolys, 0, text->GetMaxError(), ERROR_INSIDE );
                 }
-                else
+                else if( item->Type() != PCB_REFERENCE_IMAGE_T )
                 {
                     item->TransformShapeToPolySet( *copperPolys, layer, 0, item->GetMaxError(), ERROR_INSIDE );
                 }
@@ -740,6 +743,9 @@ void BOARD_ADAPTER::createLayers( REPORTER* aStatusReporter )
                     break;
                 }
 
+                case PCB_REFERENCE_IMAGE_T:     // ignore
+                    break;
+
                 default:
                     wxLogTrace( m_logTrace, wxT( "createLayers: item type: %d not implemented" ), item->Type() );
                     break;

pcbnew/board_item.cpp

@@ -304,7 +304,7 @@ void BOARD_ITEM::TransformShapeToPolygon( SHAPE_POLY_SET& aBuffer, PCB_LAYER_ID
                                           int aClearance, int aError, ERROR_LOC aErrorLoc,
                                           bool ignoreLineWidth ) const
 {
-    wxASSERT_MSG( false, wxT( "Called TransformShapeToPolygon() on unsupported BOARD_ITEM." ) );
+    wxFAIL_MSG( wxString::Format( wxT( "%s doesn't implement TransformShapeToPolygon()" ), GetClass() ) );
 };