Are the Boolean operations hopeless?

I’ve been trying for two hours to try and get the boolean operations to work consistently for me. The mesh I’m making is going to be used in a fabricating machine, so the mesh doesn’t need to be at all tidy, just geometrically accurate.However, I can have no overlapping geometry at all in my mesh, otherwise the fabricator throws it out. The thing that we’re fabricating is something I made years ago, however, it has a lot of overlapping stuff. I figured I could just boolean it all together into one large mesh. However, Blender is being uncooperative.

I have taken each object, made sure there are no doubles, recalculated all the edge normals outside, applied all scales and rotations, ensured there are no non-manifold edges, but still I cannot get it to behave as expected. It doesn’t matter if I convert the quads to tris or vice-versa, the boolean tools always seem to make faces or whole chunks of the geometry dissapeal.

I already told my boss this would only take a few days, but if I have to redo the whole thing from scratch I’m looking at weeks of overtime. Is there any secret to making the boolean operations work as one would expect them to work?


Blenders booleans are not all that. Try selecting one object then one other
and W Union. The key being one at a time.
Failing that post the .blend and I can take a look.

Kindest Regards,


also, do a visual check (“draw normals”) to confirm that normals are outwards. can be problems if objects have coplanar/coincident faces