Weird problem with Z axis

#1

Hi all, I am following an animation tutorial and I am having a difficult time figuring out this problem. Basically I am transferring over the values from one side to another on the arm. On the Z axis say the arm’s value is -58 and when I transfer it to the other arm which is 58 I shoots right into the air. I have used two rigs so far and it happened to both. I am using Maya 2009, please help. Thank you.

#2

Hey Jorge, it sounds like a problem with the rig (namely the rotation axis of a bone isn’t quite right). Try placing the value of 58 in Y or X and see if that helps.

#3

Hey Paul, thanks for the response, well after wasted hours trying to figure this one out, I experimented with three rigs. the “Andy” rig, the “blake” rig, and finally “animo” the digital tutors rig. The first two rigs could be found from Creative Crash, what used to be Highend3D. Anyways, When I use “Animo” the reverse values work just fine, meaning if one side is -10 on the Z the other side is 10 and the mirror effect works. However, with Blake and Andy, if you input -10 on Z or Y, you can put -10 on Z or Y, HOWEVER the X axis is the only one that needs to be input with the reciprocal in the opposite side and get the mirror effect as well. What does this mean?

#4

If I understand you correctly, then it is as I suspected. When a skeleton is created in Maya, each bone has an ‘orientation’. It has a local x,y,z axis that points in a certain way (maybe with x along the bone, and y upward and z perpendicular to y). Check this page out with images of the rotation axes visible on bones.

This orientation will affect rotation and translation of the bones. So in your ‘broken’ rigs, the two arms should have orientations that are identical with the exception of one axis being negative of the other. If they are oriented in this way, in opposite directions, then by placing a positive value in one you place a negative value in the other arm and they move in a mirror like fashion. If they are oriented in totally arbitrary directions then a positive value in Z may need a negative Y (or a positive X or…) on the other arm - it all depends on the orientation of those axes.

There are tools in Maya to correct these orientations. Rigs that don’t work as you expect (mirroring of two arms) need to be experimented with (or you need to display the local axes) in order to determine which axes are the mirror axes of the other…

Anyway, hope that doesn’t cloud the water too much!

#5

Oh my goodness, how did I not think of that. I guess because these rigs are so “standard” that I did not think they would have orientation flaws. Thank you very much.

#6

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