diff --git a/libsrc/meshing/meshfunc2d.cpp b/libsrc/meshing/meshfunc2d.cpp
index 88955a36..84f5d399 100644
--- a/libsrc/meshing/meshfunc2d.cpp
+++ b/libsrc/meshing/meshfunc2d.cpp
@@ -20,6 +20,19 @@ namespace netgen
       }
     mesh.Compress();
 
+    bool optimize_swap_separate_faces = false;
+    if(!mp.quad)
+    {
+      bool mixed = false;
+      ParallelFor( Range(mesh.GetNSE()), [&] (auto i) NETGEN_LAMBDA_INLINE
+          {
+            if (mesh[SurfaceElementIndex(i)].GetNP() != 3)
+                mixed = true;
+          });
+      if(mixed)
+        optimize_swap_separate_faces = true;
+    }
+
     const char * optstr = mp.optimize2d.c_str();
     int optsteps = mp.optsteps2d;
 
@@ -31,16 +44,42 @@ namespace netgen
 	    {
 	    case 's': 
 	      {  // topological swap
-		MeshOptimize2d meshopt(mesh);
+                MeshOptimize2d meshopt(mesh);
                 meshopt.SetMetricWeight (mp.elsizeweight);
-		meshopt.EdgeSwapping (0);
+
+                if(optimize_swap_separate_faces)
+                {
+                  for(auto i : Range(1, mesh.GetNFD()+1))
+                  {
+                    meshopt.SetFaceIndex(i);
+                    meshopt.EdgeSwapping (0);
+                  }
+                }
+                else
+                {
+                  meshopt.SetFaceIndex(0);
+                  meshopt.EdgeSwapping (0);
+                }
 		break;
 	      }
 	    case 'S': 
 	      {  // metric swap
 		MeshOptimize2d meshopt(mesh);
                 meshopt.SetMetricWeight (mp.elsizeweight);
-		meshopt.EdgeSwapping (1);
+
+                if(optimize_swap_separate_faces)
+                {
+                  for(auto i : Range(1, mesh.GetNFD()+1))
+                  {
+                    meshopt.SetFaceIndex(i);
+                    meshopt.EdgeSwapping (1);
+                  }
+                }
+                else
+                {
+                  meshopt.SetFaceIndex(0);
+                  meshopt.EdgeSwapping (1);
+                }
 		break;
 	      }
 	    case 'm':