The ability to change rotator/hinge angles in the designer

I've needed this for a while, when making complex hinged mechanisms, i have to rely on trial and error to check if the maximum angle is perfect.
This could work like a slider that goes from the minimum angle to maximum angle, and rotates the hinge part in the designer, rotating what is attached to it too.
This could apply for pistons, hinges, rotators, and maybe even engine gimbal.