Hi wisty,

> Thanks. How do you spot something like that? Is there a "console" that reports errors
> etc, or is it simply a question of searching.

There isn't any console for error checking as of yet, that is something that I do want to work on in the future though.


> What confused me was that If I tried to trim the part with a simple straight line, I got the same effect.

Well it is normal for the result of Trim to be surfaces instead of solids - Trim is a surface operation and cuts up just the surface skin of a solid or surface alike. It's the boolean commands that can work to preserve solids making "side walls" for cuts.

So using a line in boolean difference will produce the kind of result you want, Trim will break it from a solid into surfaces.

- Michael