Creating a bounding box for a room

Hey there guys, I have been playing with my code creating a table that will different angles of legs and different surfaces when you select different points and play with the sliders.

This is for a project at School of Design and I am doing this to provide an internet service for people to create their own furniture.

I need help to modify the "room" parameters I have set up in the file attached but it needs to cut the poles when they exceed the boundaries so that we can see the correct angles and sizes according to room size.

Any help would be appreciated.

Thank you.

James