Hi Guys,
I’am a newbie to Blender and finding my way around. I will use blender for 3D printing modeling. Today however I found a problem I can’t fix. So hope someone is outhere to help:
when I use the Boolean difference tool I end up with the two objects joined instead of a hole in the first cilinder. I have two cilinders of which the first is modified by hand (front and back have triangle faces). I think that might be the problem because if I use 2 regular cilinders I have no problems at all. I’ve tried remeshing the first cilinder, recalculate normals and subdivision surface but that didn’t help. That did help to not crash all the time 
…
Anyone have a suggestion?
thx…Barry
PS: Because of holiday season I might not be at my desk all the time to reply imediatly…