For the buildings in our game, both interior and exteriors, I currently have “use Complex as Simple” for collision on the models because there is a lot of pieces to the building I want to have collision for. How expensive is it for a static object to have this?
It depends on the poly count of the mesh, as far as i know.
Well lets say the buildings are only a couple thousand poly.
Jacky is right. Complex as simple is per poly and can be a performance hit, but more so for movable objects. Static objects are not as bad, but if you you can use custom collision or simple collision boxes created in the Static Mesh Editor for your mesh this would be the best route to take.