# Topology question (square hole in cylinder)

I have a cylindric shaped mesh with two faces that has been extruded into the cylinder. I am using subsurf and the extruded part is naturally curved due to the subsurf. I need the extruded part to be almost 100% cubic and not curved. I know i am probably doing this wrong but right now i dont know any other way. Creasing doesnt give a decent result so that is out of the question. Model it another way? Interesting but how? Or maybe there is a solution to my problem?

I have added a screenshot to ilustrate.

• Hello :). What exactly do you mean by "creasing doesn't give a decent result"? It seems to work great on my end. Jun 5 '20 at 21:00
• The mesh in the ilustration is not the same mesh as i am doing this on. That mesh has diferent topology. I reckoned that a posible solution to my question would remove the issue anyway. Sorry for not being precise in the information given. Jun 5 '20 at 21:10

This kind of topology will work fine for a 16 vertex cylinder, a bit more complicated for a 12 vertex cylinder:

There's a trick to avoid pinching with the Shrinkwrap modifier:

Create a cylinder at the exact same place and with the exact same diameter. Hide it.

On your original cylinder, create a vertex group around the square hole.

Give your cylinder a Shrinkwrap modifier with the hidden cylinder as Target and Vertex Group > Choose the group you've created.

• Yeah that looks like a good solution. Only i dont know how you made that. And how can i do that without mirror? Jun 5 '20 at 21:02
• ok I've edited, you need to begin with a bevel, then join some vertices and dissolve edges Jun 5 '20 at 21:18
• This is a good solution. It didnt make the are completely square like i wished, but it is so close..... Jun 5 '20 at 21:41
• Then you need to begin with more vertices, like a 32 vertex cylinder Jun 6 '20 at 5:26
• I tried that too, it doesnt get completely squared but its close. Jun 6 '20 at 9:42

You can use loopcuts on the part of the cylinder extruded inwards, and it will sharpen the side the closer you move the cut to each side. Ctrl+L to add a loop cut to a side in edit mode.

• Using edgeloops like you say only makes the loops follow the shape that the subsurf provides. It does not make the area squared,,, Jun 5 '20 at 21:15