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Broken rendering of mesh (ngon filling)
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Description

System Information
Operating system: W10
Graphics card: nvidia970

Blender Version
Broken: (example: 2.80, RC1)
Worked: never, I can see this problem even in 2.79b

Short description of error
Screenshot below shows the problem. If I move any of the vertices of the mesh or change object's origin it got fixed.

Exact steps for others to reproduce the error

Event Timeline

Not exactly sure how this mesh has been created?, but somehow the filling of this ngon has a problem.
might be a numerical problem in this very specific case that leads to a borked winding/normal.
mesh seems to be valid otherwise (mesh.validate() returns False)
also tried re-sorting mesh indices, but that doesnt seem to have an effect...

other solutions:

  • flip normals solves the problem
  • delete only faces, fill again solves the problem as well

wouldnt consider this a bug, but maybe @Clément Foucault (fclem) or @Campbell Barton (campbellbarton) could shed some light on the exact reasons why this happens...

It is strange that glitch appear only when mesh is on the certain positions.
Only in the certain x-positions Blender tries to connect vertices wrong. Y positiom changes nothing.

Philipp Oeser (lichtwerk) triaged this task as Waiting for Developer to Reproduce priority.

Will assign to @Campbell Barton (campbellbarton) for the time being...

Philipp Oeser (lichtwerk) renamed this task from Broken rendering of mesh to Broken rendering of mesh (ngon filling).Aug 5 2019, 9:30 AM
Campbell Barton (campbellbarton) lowered the priority of this task from Waiting for Developer to Reproduce to Confirmed, Medium.Aug 5 2019, 11:45 AM