Intersection line between two surfaces

Postolje topa.3dm (83.6 KB)

Here I have (attachment) the segment of the main deck and the base for the cannon. I want to remove the under deck part of the base and obtain a flattened surface of the upper part of the base. The problem is how to remove lower part of the base.
Please, can somebody help me?
Thank you a lot! :slight_smile:

did you try the commands Split or Trim?
is that what you are trying to achieve?

Thank you a lot. Trim command did the job I needed.
Kind regards, Hrvoje