What is wrong with my boolean?

Hello, i’m trying to do what I thought is a simple boolean, but the result is very far from what I expected. I can never seem to get booleans to work. Any pointers on what I’m doing wrong? I am trying to subtract the 5 cylinders from the plate to leave clean holes. Instead I get only 3 holes and some buggy geometry.
i pressed apply transform and apply scale beforehand.

in the Boolean options, have you chosen Fast or Exact? Exact works better as it tolerates overlapping faces and vertices

OP is on 2.90.1, Exact and Self are only available in 2.91.

I do not see where I can select the quality of the boolean. I am using blender 2.91
edit: I thought I was on 2.91 but that’s apparantly not so.

oh I don’t know how you saw that but ok :wink:

No, you’re using 2.90.1 :slight_smile: The Exact and Self options only became available in 2.91. In your case, you can just separate the cylinders and do the three holes first, and the two others second. Or boolean the cylinders between each other first, piecemeal. Booleans don’t really like self-intersecting geometry.

Bottom right corner of screenshot :wink:

Thanks, I tried doing them one at a time and that worked better. Still need a lot of cleanup of geometry though but that is expected I suppose. However I will update my blender and see what differences these new modes will make for future operations since I like to work with array and then boolean the result, it would be too much to do manually sometimes.

one of your problem is the cylinders in the array intersects
in blender 2.91, put a boolean after the array, operand type to collection
crazy hack but it work