Hi Corzair - now I see the other part of your message:

> Also when I extrude a planer object then make cuts/trims the resultand object ends opened

That's normal for Trim, Trim will cut the surface "skin" of an object, it won't preserve a solid.

Instead of Trim, use Construct / Boolean / Diff for this - the booleans will cut a solid with a curve and leave a solid result.

- Michael