diff --git a/libsrc/csg/csgeom.cpp b/libsrc/csg/csgeom.cpp
index 82102118..8eb82ce7 100644
--- a/libsrc/csg/csgeom.cpp
+++ b/libsrc/csg/csgeom.cpp
@@ -949,6 +949,7 @@ namespace netgen
   {
     int inv;
     int nsurf = GetNSurf();
+    identicsurfaces.DeleteData();
 
 
     isidenticto.SetSize(nsurf);
diff --git a/libsrc/csg/python_csg.cpp b/libsrc/csg/python_csg.cpp
index 12545eee..f66f61c6 100644
--- a/libsrc/csg/python_csg.cpp
+++ b/libsrc/csg/python_csg.cpp
@@ -676,6 +676,7 @@ However, when r = 0, the top part becomes a point(tip) and meshing fails!
     .def("Draw", FunctionPointer
          ([] (shared_ptr<CSGeometry> self)
           {
+             self->FindIdenticSurfaces(1e-8 * self->MaxSize());
              self->CalcTriangleApproximation(0.01, 20);
              ng_geometry = self;
           })
@@ -705,8 +706,8 @@ However, when r = 0, the top part becomes a point(tip) and meshing fails!
                auto surf = csg_geo->GetSurface(i);
                surfnames.push_back(surf->GetBCName());
              }
-           csg_geo->FindIdenticSurfaces(1e-6);
-           csg_geo->CalcTriangleApproximation(0.01,100);
+           csg_geo->FindIdenticSurfaces(1e-8 * csg_geo->MaxSize());
+           csg_geo->CalcTriangleApproximation(0.01,20);
            auto nto = csg_geo->GetNTopLevelObjects();
            size_t np = 0;
            size_t ntrig = 0;