View Full Version : Armature Constraints - knees and elbows - noob question

04 April 2005, 01:26 PM
Greetings -

I'm trying to build a decent armature - and I'm getting a little stuck on how to make certain joints (knees, elbows) behave properly.

1) My biggest concern: knees and elbows are "hinge" joints, but the default blender armature joint is more like a ball and socket joint. Is there a way to make an armature joint behave more like a knee or an elbow?

2) If that's possible, can I further constrain the movement so that the joint doesn't flex "backwards" - i.e. build in a range of motion in the joint from 25 to 175 degrees or something?

I've searched this forum, read the blender docs, but I can't figure this one out... Thanks...

04 April 2005, 10:57 PM
yah.. I'd like to hear some answers from those questions as well... Anyone? Speak up...

- Ian

04 April 2005, 03:36 PM
Becasue that's not possible yet. :scream:
Sorry guy but this is a feature yet to come before sigg. of this year. for now you can fake it using an other ik solver in the middle of the chain to kind of pull the join to the back or front of the character so it doesn't go backwards. This might be usefull to you:
look under ik constraint to se how to set a multiple ik solver chain. and take a look at the numerous .blend example. This one is a good example:

04 April 2005, 10:30 PM
I've been using that type of hacks since a long time.

In my signature there is a link to download a fully rigged character, it uses extensively that sort of joints.

04 April 2005, 05:39 AM
Gabio, Great suggestion. Nozzy's skinney guy is outstanding! I was going to suggest the same.

lardlad, Study Nozzy's rig, reverse engineer it. You'll get a a good insight how to handle the knees and elbows. He also has another one on a hand rig.

04 April 2005, 01:09 PM
Thanks, all. I've got a whole Sunday to reverse engineer and try to learn from the masters. From what I can gather, Maya accomplishes hinge joints with "Rotate Plane Solvers" - I might poke around on projects.blender and see if this is in the pipeline...

Thanks again

05 May 2005, 10:49 PM
While I was playing around with the afforementioned excellent examples, I found my own weird solution. It's kinda klugey, but it works okay. Here's a page ( with a link about it...

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05 May 2005, 10:49 PM
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