Set union between two surfaces

[mix]

Hello, Is there a way to find the intersection of two surfaces and discard the rest? Sort of like a trim command? The only thing i could think of was the union nodes but neither one of those worked. Is there a work around for this sort of thing? thanks in advance!

[Danos]

Geometry.intersect?

[mix]

Well using that I am able to get only the line of the intersection. My problem is that it needs to be a hard corner like the one on the bottom side. if I run a polysurface over this, I get a “stretched” look. any ideas?