Hi mk1978, it tends to be more difficult for the booleans to process objects that have overlapping surface areas, it makes for a more complex intersection.

It can work though if the pieces are accurately placed. In your your case here things are off by a bit:





Like corchet mentions above, it's also not so good to have large coordinate values for your objects like having it 10000 units across.

In the attached file, I scaled your objects down by 1/100 in size so they don't have overly large coordinate values and I also just moved your pieces so they were accurately in place and now the boolean should work ok.

- Michael