diff --git a/lib/Slic3r/Layer/Region.pm b/lib/Slic3r/Layer/Region.pm
index 06345ac86..6ce755b7b 100644
--- a/lib/Slic3r/Layer/Region.pm
+++ b/lib/Slic3r/Layer/Region.pm
@@ -496,7 +496,8 @@ sub process_external_surfaces {
             $angle = $bridge_detector->angle;
             
             if (defined $angle && $self->object->config->support_material) {
-                $self->bridged->append($_) for @{ $bridge_detector->coverage_by_angle($angle) };
+                $self->bridged->append(Slic3r::ExPolygon->new($_))
+                    for @{ $bridge_detector->coverage_by_angle($angle) };
                 $self->unsupported_bridge_edges->append($_) for @{ $bridge_detector->unsupported_edges }; 
             }
         }
diff --git a/xs/src/libslic3r/Layer.hpp b/xs/src/libslic3r/Layer.hpp
index 115a728e0..bd87ab0cb 100644
--- a/xs/src/libslic3r/Layer.hpp
+++ b/xs/src/libslic3r/Layer.hpp
@@ -40,6 +40,7 @@ class LayerRegion
 
     // collection of expolygons representing the bridged areas (thus not
     // needing support material)
+    // (this could be just a Polygons object)
     ExPolygonCollection bridged;
 
     // collection of polylines representing the unsupported bridge edges