Automating Continuous Movement?

Ok, so I have a Sci-fi vehicle and I need some help with continuous movement.

I want the two turbines to be able to spool up, run, and spool down through the control of the “turbine control” bone. I know about the continuous modifier, but that’s not quite what I’m looking for. My problem with the continuous modifier is that if you need to activate and deactivate it multiple times, it becomes a hassle. I figure the spool times can be accomplished by messing with the graph editor when moving the controller, but the question still stands: How do you get continuous motion with a controller?

I don’t think you can. Not without some complicated scripting that’s only going to work when playing it all the way through from frame 1. (Have to remember the frame number of the most recent significant change to the controller, as well as the rotational transform of the controlled object at that frame, in custom properties, via a script to prevent dependencies, in order to do it right.)

But here, where your rotational speed is going to be so large that transform errors are going to be lost in the sea of sampling error, even at 144hz, you could get away with having the controller drive the influence of a copy rotation constraint, targeting something else with a cyclic fcurve.

Alright, the copy rotation constraint seems to work. You need to be sure to set the copy rotation to add the rotation instead of replacing it, but it does appear to be working. Thanks!