Boolean operator on cone

I am using blender 3.1.0 and have a strange issue when using the boolean operator on a cone.

What I did/tried is the following:

  • add cylinder and decrease the size at the top
  • created the window using a cube and beveled the upper part (however, with the standard cube, the same issue appears)
  • selected shade smooth for the cone
  • set normals to autosmooth 30°
  • applied boolean modifier (difference, exact)

I however get the weird behavior at the top of the “window”. When using a normal cylinder, this does not happen. Only when I decrease the size of the top.

Does anybody have an idea on how to solve this issue?

FYI: I want to create a lighthouse with windows+door

Welcome :tada:,
this is properly because of the topology of your cylinder… i assume some edges like in red… you may reduce this by adding something like the green ones:

YOu may also be better off by constructing the boolea manually here… for example using “matching” subdivs of the window…

i would recommend watching this tutorial:

especially at 3:10 you see how the topology should look like

in short: avoid ngons, try using quads whenever possibel.

Thanks a lot for the fast feedback.

I added some loop cuts and placed them close to the windows. Now, it looks fine.


very nice one!