I'm attempting to cut a neat hole in a cylinder using minimal topology. I've used an octagon for both the cylinder and the hole. On applying the subdivision surface modifier, the region near the hole curves out a bit intersecting with parts of other objects which isn't supposed to happen with a perfect cylindrical surface. How may I correct it?

side view front view

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    $\begingroup$ maybe try this method: blender.stackexchange.com/questions/194716/… ... it consists on using another cylinder as target of a shrinkwrap, it allows you to correct the shape of your cylinder. If it still doesn't work, please share your file $\endgroup$
    – moonboots
    Sep 24, 2020 at 9:02
  • $\begingroup$ @moonboots Thanks! Yes that would work. But the required levels of subdivision has to be applied prior. Bending a fully subdivided plane would be another method which I actually did. But obviously has the same requirement as the former. $\endgroup$
    – jais
    Sep 29, 2020 at 18:20

1 Answer 1


When you create a low poly cylinder and then add a subsurf it creates a high poly cylinder but with a smaller diameter because the surface will be inscribed into the low poly cylinder's volume.

You have to push inside a bit the loop of your hole: enter image description here


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