diff --git a/src/Mod/CAM/Path/Main/Gui/SimulatorGL.py b/src/Mod/CAM/Path/Main/Gui/SimulatorGL.py
index 55d2403fbd..be96af3d9e 100644
--- a/src/Mod/CAM/Path/Main/Gui/SimulatorGL.py
+++ b/src/Mod/CAM/Path/Main/Gui/SimulatorGL.py
@@ -92,18 +92,24 @@ class CAMSimulation:
         for edge in edges:
             p1 = edge.FirstParameter
             p2 = edge.LastParameter
-            rad = RadiusAt(edge, p1)
-            z = edge.valueAt(p1).z
-            if IsSame(px, rad) and IsSame(pz, z):
+            rad1 = RadiusAt(edge, p1)
+            z1 = edge.valueAt(p1).z
+            if IsSame(px, rad1) and IsSame(pz, z1):
                 return edge, p1, p2
-            rad = RadiusAt(edge, p2)
-            z = edge.valueAt(p2).z
-            if IsSame(px, rad) and IsSame(pz, z):
+            rad2 = RadiusAt(edge, p2)
+            z2 = edge.valueAt(p2).z
+            if IsSame(px, rad2) and IsSame(pz, z2):
                 return edge, p2, p1
+            # sometimes a flat circle is without edge, so return edge with 
+            # same height and later a connecting edge will be interpolated
+            if IsSame(pz, z1):
+                return edge, p1, p2
+            if IsSame(pz, z2):
+                return edge, p2, p1           
         return None, 0.0, 0.0
 
     def FindTopMostEdge(self, edges):
-        maxz = 0.0
+        maxz = -99999999.0
         topedge = None
         top_p1 = 0.0
         top_p2 = 0.0
@@ -137,7 +143,6 @@ class CAMSimulation:
                 sideEdgeList.append(edge)
 
         # sort edges as a single 3d line on the x-z plane
-        profile = [0.0, 0.0]
 
         # first find the topmost edge
         edge, p1, p2 = self.FindTopMostEdge(sideEdgeList)
@@ -167,6 +172,12 @@ class CAMSimulation:
             edge, p1, p2 =  self.FindClosestEdge(sideEdgeList, endrad, endz)
             if edge is None:
                 break
+            startrad = RadiusAt(edge, p1)
+            if not IsSame(startrad, endrad):
+                profile.append(startrad)
+                startz = edge.valueAt(p1).z
+                profile.append(startz)
+                        
         return profile
 
     def Activate(self):
diff --git a/src/Mod/CAM/PathSimulator/AppGL/EndMill.cpp b/src/Mod/CAM/PathSimulator/AppGL/EndMill.cpp
index 49932830ec..829e4089f3 100644
--- a/src/Mod/CAM/PathSimulator/AppGL/EndMill.cpp
+++ b/src/Mod/CAM/PathSimulator/AppGL/EndMill.cpp
@@ -62,7 +62,8 @@ EndMill::EndMill(const std::vector<float>& toolProfile, int toolid, float diamet
         profilePoints[i] = toolProfile[i] + 0.01F;  // add some width to reduce simulation artifacts
     }
     if (missingCenterPoint) {
-        profilePoints[srcBuffSize] = profilePoints[srcBuffSize + 1] = 0.0F;
+        profilePoints[srcBuffSize] = 0.0F;
+        profilePoints[srcBuffSize + 1] = profilePoints[srcBuffSize - 1];
     }
 
     MirrorPointBuffer();