Boolean question

in the attached file why, when I subtract the green cube from the gray surface do I get a finished cut and joined box rather than just a hole in the gray surface?
TEST 001.3dm (80.2 KB)


Hi Dennis - Boolean operations decide what to do based on the input directions - on open objects that could be either way - so Flip the wall to get the opposite results, or cycle through BooleanTwoObjects. It can be helpful to set your display mode with colored back faces so that you can easily tell which side Rhino considers to be the ‘outside’. If you do not agree, use Flip.


Hi Pascal,

That just gives me an opening with top sides and back pointed the other way. What I want is a hole in the plane with no depth.

Hi Dennis - use Trim for this, not a Boolean.


Ah. Thanks again.