Stitch trim Surfaces vs. Add Solids

[Horst M.]

Hallo,

During evaluation of some Symbols that I imported from dwg Files, I dicovered the following:

The Symbol in the example imports as 70 NURBS Surfaces

which slows down all Pan Zoom and 3d Display Operations a lot, even in Wireframe. (there were 8 of these Symbols in the file)

I opened the symbol(s) and executed "Stitch trim surfaces" from the 3d Powerpack.

The result is 2 CSG Solids which can be cut, and modified with the Push pull tool and so on.

If I execute the "Add Solids" comand on the 70 NURBS Surfaces, I get 1

Solid addition, which can hardly be modified with the Push pull tool and can't be cut.

Is there any explanation for these Effects, or can somone explain the differenc of the results?

In both cases VW gets speedy and smooth in Pan Zoom and other 3d Display Operations, if I do this to Symbols that are imported as NURBS Surfaces Bunches.

Horst M.