"Set Driven Key" equivalent? (Sliders?)

Hi all,
I used to do a lot of animating in Maya, and often used the Set Driven Key option, where you can essentially use one object (or element, whatever) to animate (or “drive”) another. This was also used with sliders, where you could, for instance, create a character and have a “wink” slider, a “smile” slider, a “smirk” slider, etc. I’m currently trying to figure out how to set this up in blender – for the most part I would like to link location, scale, and rotation values of various empties to sliders for easier animation later on. I’ve been looking around – my gut feeling is that it’s in there somewhere, but after a couple days I’m starting to lose hope. Any suggestions?

Hey for facial animation its pretty straight forward with the Shape Widget Wizard - under animation in the scripts window - thats a starting point for you. Also you can look in the contraints to do a few things - and in the ipo window if you hit the ‘N’ key while you are in the ‘shapes’ ipo you should see a driver interface- If you search ipo drivers a few tutorials will come up - http://www.youtube.com/watch?v=z6AWO5cmb_I – good luck

Hey benu,

I have also written an explanation of this a few posts down in the Rigging Help & Techniques thread. Hopefully you find it useful as well…


what he said. Basically you use IPO curves, and give the IPO curve a driver object. (press N to assign a driver object in the IPO window)
The IPO curve drives the constraint/shapekey, and the curve is in turn controlled by the driver object.

You assign an IPO curve to a constraint or shapekey. (press, show, and/or key on the constraint, or open up an IPO window, set the display to shape or constraint, whatever floats your boat, and key away.
For instance, if you have a slider where a constraint influence at no movement from the driver object (I use in armature bones) is 0 (say you have an IK chain, and a chain for the FK that is constrained (copies) the IK limb’s rotation, when I disable the rotation constraint, it will behave as FK)
Then the curve would have 2 keys. One at x=0 y(strength/weight)=0. If you move the driver object 2 units to have full effect (constraint/shapekeys value/weight=1) you’d have the other key at x=2, y=1.

Be sure to disable the “shark attack victim” icon, so the driver doesn’t become part of the action (causes refresh issues, it’s a design issue and will be solved in 2.5)

Thanks for the replies! I’m going to try to put it all together tonight…

try not to use external empties, just create some new bones to act as the slider. It’s easier to manage your rig if you keep as much as possible in armature. At least, that’s what I think.

EDIT: keeping sliders in-armature may also help to avoid some refresh issues (where you need to skip a frame for things to be refreshed, because stuff in armature is evaluated before stuff outside of the armature.)

Worked great. FreakyDude: I used armatures as you suggested – it looks like a set of little levers that I move around the scene as needed while animating. THANK YOU ALL!