Rotation axis corruption

#1

After searching the internet it seems no one is having this problem, or maybe I just don’t know the right words to search for this. Here’s my problem:

When I rotate a joint on my skeleton, sometimes an axis doesn’t follow. I know it sounds confusing so to make it more clear, I took some screenshots.


See how the Z and X axis get closer to each other?
I have no idea what creates this problem. Playing around with that same joint, sometimes it works fine and sometimes it doesn’t. Another effect of this problem is that when the axis get closer to each other, afterwards when I change the value of one, it changes the value of the 2 other axis too.

Even though with a lot of work I can get to the position I want to, I can’t animate anything because it makes the movement of my bone go in weird dirrections as the values change.

I really don’t understand what I might’ve touched to make it act all weird like this and I’m desperatly searching for an answer as this is a homework and it’s due for right now…

#2

Fortunately/Unfortunately you are not the only one to have had this problem. The term you want to search for is gimbal lock! You will have more to read about then you have time to read. There are a few threads on here that discuss the issue at length. Its definitely worth reading about.
Some animators ignore gimbal altogether by rotating in Local/World space…some like to break up rotations on to different controls to avoid gimbal issues.
The rotation order option on the transform node changes the…um…rotation order. Which can help a bit depending on the axis used most often on any given control/joint.
Good luck on your crusade against gimbal lock!

#3

Thanks for pointing that out for me. I’ll provide the solution I found. I simply grouped the joints I want to animate and I control those groups’ rotation instead.

#4

Yep, that’s one way to do it…glad you got it working!

#5

always remember, gimbal lock CANT be removed but only can be avoided.

#6

I noticed that I always get it when I change the value of an axis directly in the channel box. Sometimes it happens if I change it on only one axis (Y in my exemple) and sometimes it doesn’t matter which axis I choose. Now I always make sure to save before rotating an axis and if the gimbal lock happens, I just reload the scene to right before I manipulated it.

#7

truly speaking, i am rarely affected by gimbal lock situation for bones.
just few basics, never move ur bones. in maya, just select all the joints and say orient joint. select last one and say orient joint (with none option).
i get struck with controllers few times, but grouping (or i made a small script for it) just solves my issues all the time.

#8

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