Sunday, August 16, 2009

Gimbal Locks!

OK, so working on my 11 Second Club animation, I stumbled across one problem: Gimbal Locks. What are those? A good explanation can be found here.

What I understood about them is that a Gimbal Lock occurs when two axis meet each other, i.e. they have the same orientation. Check the link above for a better explanation! :P

Anyways, what should you do when you have them? You can find a lot of information about how to avoid them, but what about when they are already there? Well, I found two ways around this problem.

The first one is to switch from IK to FK. This is the first solution I came up with. However, it can be a VERY tedious process. The second solution will work better during the first linear pass or during the blocking process (Gimbal Locks are another good reason to do the blocking in linear, since in stepped mode you won't be able to see them). You'll have to copy ONLY the ORIENTATION key from the previous key to the key that is screwing your nice animation. Get it?

OK, an example. Let's say in frames 40 and 50 you have these nice poses on the right hand. However, the way the hand goes from frame 40 to 50 defies human mechanics by far. Check the following video for an example:

What I did was to copy the orientation key from frame 40 to 50. Once you do this, you might have to adjust the new orientation in frame 50, but that's far more easy than switching from IK to FK. Another complication is that all the following orientation keys will be screwed up. But no worries, the time you'll spend repeating this process of copying on orientation key to the next one and readjusting is not that bad, and the animation will look far better. Oh! and do NOT copy the other keys (position, scale, CAs, etc) since it will (badly) mess up you nice pose.

OK, this are my two cents in this subject. I wanted to write about something else, but I forgot.

C U next time!


No comments: