View Full Version : Joint orientation is off???

 tannerj02 February 2005, 04:27 AMHey everyone, I'm a senior in high school and i've kinda been messing around with maya for about 3 years now... learning a little as i go... Well this year i've decided to do my senior project on 3d animation. I'm doing a tony hawk pro skater type 30 sec. animation. My problem is this... I've rigged my character up...very simple rig, just the basics with reverse foot rig and the rest i've followed the unreal tournament tutorials for. But i've noticed now that (and i'm not sure if this is the correct terminology) the orientation of the joints do not match up with each other or the world orientation... By this i mean that the y direction in the joints don't match each other or the world orientation... This is the second time i've rigged my character and the first time my mentor told me that this was a problem. He also made the comment that he wanted me to learn to find the solutions to my own problems...so here i am... Can anyone shed some light on this story for me??? Thanks, TannerJ.
seven6ty
02 February 2005, 07:38 AM
You don't want your joint orients lined up to the world axes.

You want them lined up in relation to the joint itself. Usually, you'll want your X-axis pointed down the length of the joint. Then, just try to make sure that all your Z and Y axis on all the joints in your heirarchy are all pointed in the same general direction. I.e.: All your Zaxes are pointed left and/or up, etc.

tannerj
02 February 2005, 10:08 PM

I went back and looked...and the joints at the ends of the hierarchy, such as finger tips, arn't pointed down...but i think that is suppose to be that way...but for example, I followed the Unreal Tournament tutorials...and for the arms they made the skeleton straight out from the spine and then rotated the shoulders to move the arms into place...When i did this the x no longer points down the hierarchy and i mirrored over on of the legs...and in one, the x points down the hierarchy and in the other it points up the hierarchy... How can i correct these things...or do they need to be corrected?

Thanks again,

Tanner J.

seven6ty
02 February 2005, 01:06 AM
Hey. Oh yeah, I forgot about some of the little details. Like yeah, the orientation of the joints on like the very tips of the fingers and toes and such, their orientation doesn't really matter much. So yeah, they can pretty much be left alone.

The x down/up the heirarchy is alright as well. Just when you mirror the joints, a nice little detail thing to do is to go back and check the joints on either side of the skeleton... i.e., both the left and right elbows, to check and make sure that when you rotate say on the y axis, that both joints move forward, and not one forward and one backwards... But that's just little details really.

tannerj
02 February 2005, 04:12 AM
SO do I need to go back and correct these things? and even if I don't for future reference...How would I?

seven6ty
02 February 2005, 05:05 AM
Ehhh, from what I understand it's no big deal really, from what you're describing. As long as the x-axis is pointed straight up or down the axis of the joint below it, you're good. Then, like I said with the other things, they're just little details which will unify all the directions everything is turning a bit better. It'll work without them, but like sometimes I'd have my axes flipped, so my control object would end up having to rotate the wrong way, to get the joint to rotate the way I wanted it. But that's about the worst thing that could happen from what you have going, it sounds like.

tannerj
02 February 2005, 02:02 PM

So I'm assuming that there is no way to fix this for future rigging projects?

seven6ty
02 February 2005, 06:27 PM
Fix what exactly?

Also, you can export your skin weights (make sure the UV's are unwrapped first), detach the skin, do whatever tweaks on the joints you want, then smooth bind and reimport your weights.

DirtEater
02 February 2005, 08:05 PM
To realign your joint orients after you've moved things around, you just need to select all the joints and use Skeleton>Orient Joints. I think in the option box for this command you can select what axis you'd prefer to point down the length of the bone, I'm at work, otherwise I'd check for you. Good luck.

-Jason

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