View Full Version : double knee leg setup?

03 March 2004, 11:10 AM
I'm looking for a way to set up a hind leg that has more than one joint between the hip and the ankle (like a cat or a frog, or most quadropeds). I'd like to have IK that solves from the foot so that it's easy to pose. That's simple enough, but the problem of course is that then you lose control of the two joints in between. I'd still like to be able to adjust those joints (Which one gets more rotation than the other). I can't figure out how to set something like that up.

The setup I would fall back on would be controlling it like you would a reverse foot roll, but it would be cooler if both joints were affected by the IK.

Does that make sense at all? I apologise for whatever terms I'm screwing up. My english is fine, but I'm still learning Mayan.

03 March 2004, 08:55 PM
Originally posted by Morganism
I'd still like to be able to adjust those joints (Which one gets more rotation than the other).

check out "stiffness" in the attribute editor (for each joint)
be sure to check out the help on this one... I think there is something odd, like you have to have all the joints in the chain set to at least 1 for it to take effect... havent looked at it in ages... maybe it doesn't even work... like the "damping"...


03 March 2004, 05:43 AM
Thanks for the suggestion. I played around with joint stiffness, but it's not quite what I'm looking for. That only really seems to come into affect as you're moving the IK handle. You can't really use it to adjust the rotation of joints in a chain.

any other thoughts or ideas? Someone must have set up something like this before.....

04 April 2004, 09:25 AM
Alrighty, I've been futzing around with this for a month, I'm still not sure of the best way to do this. I tried setting up something based on the Jason Schleifer automated clavicle, because it seemed like a similar setup for what I wanted. It works great for clavicles, but I couldn't really figure out a good way to implement it in a leg.

Here's a recap of my goal. I would like a "foot control" that affects both the regular and reverse knee rotations during foot placement, and then a slider to adjust which knee gets more weight. Say at 0 it would be like the (lower)reverse knee is locked, and at 1 the upper knee is locked. At 0.5 it would be like an IK handle going all the way from hip to ankle, so that both knees move the same amount.

This seems like it should be simple, and maybe I'm just missing something, but I'm sure someone must have come across this before.

Thanks for the help, anyone.....

04 April 2004, 05:43 AM
have you tried using set driven keys and rotation limits?

04 April 2004, 02:51 AM
that's an interesting idea, but it's a little different than what I'm looking for. Setting limits makes the joint come to a rigid halt when they reach their limit, whereas I'm interested in setting a weight, so that it just doesn't move as much.

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