Limited cut plane

Hey everyone.

I'm currently working on a frame for a undergraduate project.

I want to make a limited cut plane to evaluate the stress in the connection between a beam and a frame. This is to help me calculate my weldings. So far i have tried using the general plane type and inserted the three points to specify my limited cut zone. But when i plot it, it just cuts the entire frame, giving me 1672 values instead the limited number i wanted.

Any help would be much appreciated!

Best regards
Nikolaj Kronborg