On Default Cube, select face, Inset it, Extrude it 'inside' the cube, add Bevel and Subdivision. This is the result.

I recently switched to the latest Blender version, and I could be wrong, but I don't remember the same behaviour in older version.

This is Default Cube, no extra vertices, no wrong face orientation.. And on Cylinder the process is working as expected. If I switch Subdivision to Simple, it looks as expected, but somewhat rough.

Why is that? What am I not understanding? enter image description here

  • $\begingroup$ It depends on your bevels I reckon $\endgroup$
    – Lauloque
    Commented Sep 14, 2023 at 20:14
  • $\begingroup$ Well, if I change 'limit method' from default angle 30 to none, then it's ok. But I still don't understand why. $\endgroup$
    – vertexed
    Commented Sep 14, 2023 at 20:38

1 Answer 1


Catmull-Clark Subdivision Surface smoothens the mesh by interpolating values of nearby vertices. If there's not enough holding loops this smoothing can actually create sharp geometry like so:

The key is to have quads wherever normals change, as well as to have the quad loops flow with a consistent way to the smoothed mesh:


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