Riging a Helicopter rotor

i am rigging a helicopter like thing and i have got everything sorted but i want to have a bone that if i scale on the x axis the rotor spins and if i scale it back it stops e.g. scale on x axis is 1 rotor rpm is 0, x scale is 2 rotor rpm is 100. you could do it by adding a driver to the coordinates of the keyframe on the y axis in the graph editor but i was told that you
shouldn’t be able to animate animation data

could somebody help me!

Attachments

problem.blend (318 KB)

I’m interested in hearing an answer too

how about this…

Create a bone to rotate the rotors. Keyframe it and set the IPO to linear extrapolation. So it is always rotating. Then add a child of constraint to the rotors model for that bone. Then create a new bone to control the influence of the constraint.

Not sure if it will work, but I think it’s worth a shot.

Nice idea Asano! I kinda had a buggy time getting this to work…but it works. I couldn’t get it to work based on scale, well I could, but the curve was reversed and for some reason I couldn’t get the curve the way I wanted it, (I still have a hard time with drivers and curves). So it works based on location of the control bone. I also found it a bit buggy using a linear curve, in that if the control bone was only moved a small amount, turning on the constraint a small amount, it didn’t rotate properly so I have a constant curve on it.

Basically, in the attached file, I have a cube with a copy rot constraint on it targeting a bone that rotates continually. The constraint is switched off and on using a second bone. It definitely needs some refinement. Blender 2.53 file, not sure if it would work in 2.49 but I would think so.

Randy

Attachments

TestRotor.blend (235 KB)

thanks. still i my opinion the fcurve properties should be animatable