Not able to use Boolean modifier on concentric cylinder and torus (normals seem ok) I'm using Boolean Modifier quite well so far, but this time I can't get it work properly. I guess it's sometihng I'm missing but I checked other answers for bolean modifiers and none of them seem to apply to my case. I have a concentric cylinder and a torus (I specify that they are concentric because if they are not concentric the modifier seems to work properly) I need to subtract the torus from the cylinder to create the housing for an O-Ring. The result are just more faces and vertexes added to the cylinder but the housing is not created. I checked normals and non-manifold but all seem to be ok. Anyone able to explain me what am I doing wrong? Sorry if duplicate, not able to find a proper answer.

Here an image that may explain the problem:


* My mistake: not "Binary mod" but "Boolean mod"

I hope it's clear what I wanted... instead of the same outer surface of the cylinder with more vertexes that you can see in the last picture I wanted a torus housing: a negative of the torus.

Here you can get my blend file
Boolean operators are known to have issues when dealing with complex interactions. Thus, it is advised to prep your meshes to minimize issues from the Boolean operator. This simply means giving the Boolean operator easy places to make cuts.

In your example, all you need to do is to add another torus with the same number of segments as the cylinder. This aligns all the torus edges to that of your cylinder, which eliminates the issue from the Boolean modifier.

Note how the wire-frames don't line up nicely in your torus, so the Boolean modifier will need to make a ton of cuts to try to modify the geometry.



I've added another torus below, this time matching the number of segments to the cylinder, and the boolean modifier works fine.




Another thing to note: having an excessive amount of vertices in close proximity to one another can also cause problems with the Boolean modifier, but that's easily fixed by scaling/moving one of the objects slightly.