Hi Wisty, yes the solid seems to be fine, it's that back-tracking loop in the cutting curve that is problematic like nameless shows.

Self intersecting areas like that will tend to mess up surface/surface intersections and volume based processing. The self intersection will make various kinds of containment algorithms to become ambiguous.

- Michael

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

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

Thanks again.

Hey wisty,

In this case, the indication for me was a subtle thicker line on that segment in viewport, that made me inspect closer and "show points". Overlapping lines or segments appear thicker/darker in MoI viewport, but it is subtle. For the Joined surface "degradation" of a solid without the user realizing, from what Michael has shared in posts here, I think he is considering a more direct notification system if something goes wrong or a solid becomes joined surface, but for now, the details window on top right is your friend.

In general, after some time with the program, you will start to have an idea of what the problem is most of the time. There are many informative posts (Michael's answers are nutshell encyclopedias usually) and video tutorials on youtube from several creators that show workflows and problem solving, when things get tricky. :)

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