Boolean - ok and not ok - help

I am trying to figure out why boolean a ‘thin’ object is working correctly in on e scene and not in an other.

i want to cut out a cylinder, and leave the inner part.
As you can see in the examples, it is working in one scene but not in the other although they are similar setups ;-S
Anybody know if there a setting for this to happen?
(edit: added the blend files)

bool-notworking.blend (634.2 KB)
bool-ok.blend (726.4 KB)

I tested and concluded that only if you delete the face that is facing towards X+ causes this. I would consider this a bug.

I checked known limitations of boolean operation. There says:

Boolean operates best on water-tight meshes, where inside/outside is clearly defined.

The following characteristics are known to give bad output.

  • Open volumes.
  • Overlapping geometry.
  • Self-intersections.
  • Zero-area faces.

While they may not fail in all situations, they aren’t guaranteed to work properly.

ha, yes, that is indeed an ‘issue’. when I close the open side of the cube and delete some faces on the other side it is working :wink:


  • Increase the resolutions of the both models

  • Play with the overlap threshold

It is normal sometimes that the intersection testing between relatively large polygons fails.