Hole in cylinder Topology 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?
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: