diff --git a/vcg/complex/algorithms/polygonal_algorithms.h b/vcg/complex/algorithms/polygonal_algorithms.h
index 1fa638bb..0c517f90 100644
--- a/vcg/complex/algorithms/polygonal_algorithms.h
+++ b/vcg/complex/algorithms/polygonal_algorithms.h
@@ -334,7 +334,10 @@ private:
         AvVert.clear();
         AvVert.resize(poly_m.vert.size(),CoordType(0,0,0));
         std::vector<ScalarType> AvSum(poly_m.vert.size(),0);
-        for (size_t i=0;i<poly_m.face.size();i++)
+        for (size_t i=0;i<poly_m.face.size();i++) {
+            if (poly_m.face[i].IsD())
+                continue;
+
             for (size_t j=0;j<(size_t)poly_m.face[i].VN();j++)
             {
                 //get current vertex
@@ -352,10 +355,14 @@ private:
                     AvSum[IndexV]+=W;
                 }
             }
+        }
 
         //average step
         for (size_t i=0;i<poly_m.vert.size();i++)
         {
+            if (poly_m.vert[i].IsD())
+                continue;
+
             if (AvSum[i]==0)continue;
             AvVert[i]/=AvSum[i];
         }
@@ -363,6 +370,7 @@ private:
 
 
 
+
     static void UpdateNormal(FaceType &F)
     {
         F.N()=vcg::PolygonNormal(F);