Trying to rotate two specific points at the center of a cylinder in such a way that when I put a 90degree pipe on those points in unreal, the pipes will be facing downwards, to simulate going into the ground.
Looked into using quaternions for this approach but I cant seem to get the rotations I desire.
Without any angle manipulation the situation looks like this, where the pipe isnt facing the cyclinder and the bottom part is floating up instead of facing down:


Applying 90 degree turns to rectify this situation, somehow ends up with pipe that visualy look like they were turned 45 degrees



No idea on what I am misunderstanding about the situation.

It's not clear (to me) what your desired goal is. Do you want the connector to be at the ends of your tube, and end up facing downwards? Can you draw out a rough sketch?