Hi Nan:

re:
> Edit2: Readded the boolean intersection - this time via a clean extruded circle from within
> MoI as you suggested. (Works great!) The result is the same though - as soon as this cut is
> in, I cannot show any points anymore. Also added that one (oddshape3-3dm). might be
> easier to analyze from within MoI.

Yes, that's correct and normal - you end up with the same situation where you have 2 faces that are joined at an internal trim edge rather than at edges of the underlying surfaces.

That's why you generally don't work in a CAD program by turning on surface control points like you do in a poly modeling program.

The way objects are structured in a CAD program using "underlying surfaces" with trim boundaries on them marking active and inactive areas of the surface means that you cannot move 3D points around like you do in a poly modeling program. Poly modeling programs do not have this concept of "underlying surface" and "trim boundary".

Although these structures take away the ability to squish around 3D points like you do in poly modeling, the thing that they give is much better boolean operations because when 2 objects are booleaned in a CAD program it does not have to fragment things into little pieces, the surfaces stay the same and only new trim curves are created on the surfaces. it's fundamentally why booleans work better in CAD programs than in poly modeling programs.

- Michael