Ik's are changing joint orientation

Become a member of the CGSociety

Connect, Share, and Learn with our Large Growing CG Art Community. It's Free!

Thread Tools Search this Thread Display Modes
Old 09 September 2008   #1
Ik's are changing joint orientation

I'm having a problem applying IK handles to a joint chain. I figure I'm making a simple mistake but I can't figure out what it is. Whenever I apply an IK handle to a zeroed out joint chain, the joints effected by the IK handle will have slightly altered joint orientation. Does anyone know what is going on? Thanks

Old 09 September 2008   #2
Did you use set preferred angles, and is was your joint chain slightly bent before IK application?
...everything will be fine, as long as nothing goes wrong...
Old 09 September 2008   #3
Thanks for helping out with my question. The set up was a leg with a double knee. The character I'm rigging was modeled with his legs spread slightly so the joint chain is straight but slightly angled to the side. There are preferred angles set into the knee joints. I've noticed that when the knees don't have preferred angles the IK seems to be applied properly but for some reason when I add in the preferred angles the orientation in the joints gets altered by the IK. I still don't understand why though. I hope that helps

Old 09 September 2008   #4
What you can do is remove the set preferred angles, and if it's possible rotate the knees in the direction you want them to bend just a bit, freeze transform, and re orient the joints.

I've found that set preferred angle only helps when you have a completely straight joint chain, and you want maya to specifically bend the mid joint in a certain direction. If you had a slight bend in your chain, though, maya forces the preferred angle, hence you might get rotation values on your joints upon IK creation. For elbows and knees, i just leave a slight bend in the proper axis so that the ik will bend from there (this is of course with zero rotation values).
...everything will be fine, as long as nothing goes wrong...
Old 09 September 2008   #5
That's not a bad idea. I'm working on a cartoon rig and most people say to make the joints straight to give animators a greater degree of flexability when creating key poses. But maybe if I add a slight bend, say 0.001 it would still give me a relatively straight leg but it would take care of the other undeterminable random rotation values. Thanks for the help.
Old 09 September 2008   #6
Thread automatically closed

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.
CGTalk Policy/Legalities
Note that as CGTalk Members, you agree to the terms and conditions of using this website.
Thread Closed share thread

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Society of Digital Artists

Powered by vBulletin
Copyright 2000 - 2006,
Jelsoft Enterprises Ltd.
Minimize Ads
Forum Jump

All times are GMT. The time now is 02:55 PM.

Powered by vBulletin
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.