If you wanted an object to rotate parametrically within a family, most Revit blogs and forums tell you to use a reference line. They also usually state, “do not use a reference plane,” with various reasons, mainly being that you can’t control how they rotate. Well, I’m here to tell you that is simply not true. Not only can you easily control a rotating reference plane, I find it can be easier to host and rotate sweeps along a plane (rather than a line).
To start off, draw a plane at an angle, and give it a parameter to flex. Modify the angle.
Depending on where/how you drew it, the plane may shift once, or it may rotate about its original intersection. Either way it will only shift once, and then it will stick. You can then move it and it will still rotate about that point (as long it is an intersection of two planes).
This is easiest at the origin, but it can be done off the origin as well. So here we have two angles, one being controlled a certain distance away from the origin.
In this instance it doesn’t matter which is drawn first: the plane being constrained by Depth or the plane constrained by Angle 2. What does matter is that Angle 2 must be tied back to Center (Left/Right) in order for it to move when Depth is adjusted (it seems that the plane must be constrained to the plane it wants to move along).
When the Depth is adjusted, the rotated reference plane also shifts.
So, why use a rotated reference plane? Well if you can use a reference line successfully (and that is the workflow you’re accustomed to), it might be easiest to keep doing that. The main reason I use them, is it is easier to host certain objects to reference planes (especially non-nested sweeps). For example, I’m working on a rotatable rock family (most objects don’t need the ability to be placed upside-down or sideways, but a rock often does).
Still working on this family, but look for a post and download soon!