Mechanical Crane Boom Rotation

Hei,

I am trying to rotate crane boom around pivot point 0 and I
want to stop rotation at 45 degree angle ?

Can somebody help me ?

Thank you.

This looks like a custom mesh so I am assuming you built it in a 3d modeling program and imported it. If so, the split it into two FBX files. One for the base and one for the boom. When exporting the boom to fbx, move the mesh so that the origin is your rotate point. The in UE4 create a new Actor blueprint and use Set Relative Rotation node on the boom. Here are screenshots of how I just did it for a catapult I am playing around with. The UpdateRotation custom event in screenshot 2 is connected to the Set Timer by Event in screenshot 1.