Additive constraints?

I think I have hit on a potentially useful trick for rigging eyes the way I want (for a couple reasons I’d rather not use track-to)… But in order to get this to work right for all head poses, I would need to be able to constrain an object’s rotation to the sum of two other rotations. Can this be done?

T

Yes you can using driven keys. Here is a sample blend:

http://members.shaw.ca/rjplus/addrot.blend

Turn the 2 red cubes on the z axis and the blue cube will rotate the sum of the 2 blue keys rotation. You can set up the other axis as well if you wish.

GreyBeard

Cool. I hadn’t known what those d- IPOs were. I’m guessing location probably works the same way. Thanks.