Hi Rich_Art,

> I try to boolean this to 1 object but it keeps calculating after 15min
> I did stop the calculation.
> any Idea??

If I delete one of the outer surfaces, you can see that the inside of the pieces you are trying to boolean have a kind of barely skimming overlapping surface area:



Those kinds of barely skimming overlaps between the pieces being booleaned can add a lot of complexity to the boolean calculation, because the boolean code is going to try and intersect those 2 barely skimming surfaces together, and if one is just bumping up and down through the other one by a tiny amount that can make for a whole lot of complex intersection curves between those objects.

So just in general surface overlap like that is a much more difficult boolean to handle. If you want to boolean together 2 pieces like that, it's better to create the indented piece to be sunken down a little bit into the other object, sort of pushing through it by a small distance instead of having 2 surfaces just barely skimming along each other.

- Michael