Wrong result by BRepFilletAPI_MakeFillet

Attached, please find a zip file with 4 brep files.
I used BRepFilletAPI_MakeFillet to create the fillet on small.brep with radius=0.002. It results in small2.brep. The same step is applied to another part (big.brep) with radius=0.2. and it results in big2.brep. big.brep is 100 times bigger than small.brep. However, the results are different. small2.brep has 14 edges and big2.brep has only 8 edges.



Forum supervisor's picture

Dear sean,

The fact that resulting shapes built with different radiuses have different number of edges is not a bug. But rather you identified consequences of another bug in fillet operation.
If you will apply the fillet operation to big.brep shape with radius less than 0.02 you will get 14 edges also. These extra edges is built because of internal bug of the fillet operation. In case of valid result (8 edges) the filleted surface consists from 1 face.
In case of invalid result (14 edges) the filleted surface consists from 3 faces with degenerated edges. It is a bug.
The corresponding issue with ID = 22882 has been registered.
Later you may check if the issue is resolved by checking references to the specified ID in OCCT Release Notes. The analysis of the issue will take some time depending on our technical capability and availability of resources.
You are also welcome to develop a corresponding patch and make a contribution via the Collaborative portal - http://dev.opencascade.org/index.php?q=home/get_involved.