I extrude this bsp a few times and now I want to bend it, usually in or maya you can select the verts and rotate it. Is there a way to do that in ue4?
I think it’s not possible to do it like that -> just select a pair of vertices and move them forward. Do this with all splits and you will get a bending bsp 
https://forums.unrealengine/showthread.php?34623-Bending-geometry