Wednesday, 10 November 2010

Gimbal Defeated!

Win! Gimbal has been put down thanks to maya and its epic controlls!

video

Here is the relatively finished rabbit sleep walk cycle. I hope your reading the relaxed swinging of the arms and light tilt of the head as a sleepwalk rather than a hunger/zombie walk, if i was to go for zombie the arms and head would be much more rigid and snappy and perhaps lunnging forwards now and then but maybe this isnt enough.

Gimbal Lock

Thought i might write a bit about how to get over it. for a handy video that explains what gimbal lock is check this out:

http://www.youtube.com/watch?v=zc8b2Jo7mno

Basically gimbal is when your rotational controls overlap eachother preventing movement in a direction that would normally have a rotational controll. this happens because of the way that rotations are calculated, the problem is the order in which they are calculated Z, moves Y, moves X, so when you move Z axis, Y and X both move the same time, if you move Y axis, Z does not move but X does, and if you move X it moves independently. gimbal usually happens when you rotate the middle axis 90 degrees causing the other two to overlap. if you try to do movement in the direction lacking an axis the motion gets calculated across two directions and comes out weird. this causes a lot of problems in animation.

The first tip id give to avoid gimbal is when rotating always rotate in gimbal view over world or local, this way you are rotating in individual axis that shows up in your curve editor making editing easy opposed to animating in local or world where two axis counteract eachother making a mess. this also enables you to spot gimbal early on.

The brute force way to fix it would be to key every frame, while it can work it reduces your ability to edit curves easily can sometimes look sketchy and takes a while. id try to aviod this unless necessary

Another 'fix' (sort of) is to have two rotation controls, so if you do get gimbal you can animate using the other rotation controll although this requires the rig your using to actually have it built in or to build it in yourself.

The best solution ive found so far is to adjust the order in which the axis are calculated in, for example rather than XYZ you could go YZX. this changes the order meaning you gain more controll in which way your controlls face, the brilliant thing is that this is a keyable attribute. so if youre having problems in one part but not another you can just key the rotational change for that section. Genious!
this cam be found in
Window > General Editor > Channel Controll
then add 'Rotation order'
this will then appear in your attribute editor!

No comments:

Post a Comment