Introduction to Maya - Rendering in Arnold
This course will look at the fundamentals of rendering in Arnold. We'll go through the different light types available, cameras, shaders, Arnold's render settings and finally how to split an image into render passes (AOV's), before we then reassemble it i
# 1 21-03-2005 , 08:23 PM
Registered User
Join Date: Aug 2004
Posts: 408

Reverse Kinematics

Hey, I'm an animator (mostly of solid objects using keyframes and path animations) and I was wondering if there was a function to switch the direction of the joint forward kinematics tool? Sure, its just as easy to create a series of small forward kinematic rotations which all add up to the movement you wished -- but is it possible to flip the direction of control so instead of controlling from the joint DOWN the chain, to control from the joint UP the chain? Sounds like an easy toggle enough to have been implemented.

# 2 24-03-2005 , 08:59 AM
Eelco's Avatar
Registered User
Join Date: Oct 2004
Location: In my dreams
Posts: 152
You can blend from Inverse Kinematics ("UP the chain") to Forward Kinematics ("DOWN the chain") to do your FK animations and back from FK to IK to do IK animations.
Follow this link and check my post in the thread in where I describe a few steps how to go about it.

Hope it's what u're looking for.

# 3 24-03-2005 , 06:31 PM
Registered User
Join Date: Aug 2004
Posts: 408
Actually, what I was trying to describe was if you have, for instance, a guy standing on one leg. When the guy wobbles, it will be around his ankle... however, if I try and move the ankle joint via rotating the joint-- the foot will move but his leg and up will not -- so instead of having a guy wobble, you'll just be clipping his foot through the ground.

Is there any way that you can toggle that moving the ankle joint will move the leg and up, but leave his foot unrotated (with relation to the ground).

# 4 25-03-2005 , 01:03 AM
Eelco's Avatar
Registered User
Join Date: Oct 2004
Location: In my dreams
Posts: 152
It's a hierarchy matter.
Just imagine it were you. When you rotate your ankle, .... you'd be moving the bones from the ankle down. Your foot only, right?
When you wobble on one leg, it's not the ankle that is wobbling, but you wobble on your feet. Your entire body is moving right, left and forward while your foot is positioned stationary. Thus the body moves around the ankle. So you move your root node in your joint skeleton instead (usually the pelvis).

The IK-handle for the leg should be set to sticky if you don't have it keyframed yet (keyframing an IK-handle will automatically make it sticky). This should keep the ankle positioned while the body moves around.
However,.. when standing on one leg, the other leg should dangle with the body. But of course you have IK-handles there too. They will keep the ankle stationary like the foot on the ground but only in the air, what you don't want. You have to blend IK/FK for this dangling leg (see previous post).

Posting Rules Forum Rules
You may not post new threads | You may not post replies | You may not post attachments | You may not edit your posts | BB code is On | Smilies are On | [IMG] code is On | HTML code is Off

Similar Threads