Thank you for your help. The curves of the network were a mix of parts from a dxf file and some freeform curves I modeled my own.
I will use the rebuild command or own freeform curves for further simplification of the model.

What do you mean with "the network of curves is technically incorrect"?

Moi generated it in a few seconds, there was no warning or error. Afterward the same with the boolean operation, it simply showed partially no effect, no warning or error.
Why is the generated solid incorrect, how can I see that? Is there a parameter I can see in MIO, for example number of vertices or degree of nurbs or anything else, which gives me an indication that solid or surfaces might become complicated or where I should be below?


Are there some further advices for an efficient generation of closed shells?

Best regard,
Paul