View Full Version : Extra Hip joint. Why?

06 June 2003, 09:45 AM
I've studied most of the online character rigging tutorials, and I've noticed that many have an extra joint in the hip. If you've tried Manus' cool new auto-rigger Animan, it builds a rig with this extra joint, and I'm curious. Why the extra joint in the hip? I'll attach two pictures of two different auto-rigging tools to better explain.

Animan (has the extra joint):

and Advanced Skeleton 1.7 (does NOT have the extra joint):

I'm curious as I'm about to start building a tutorial, mostly to help me better understand the best aspects of a good rig.


06 June 2003, 05:54 PM
Personaly, I don't use the extra hip bone... doesn't make much sense to me..

Maybe if you have a very advanced rig and for deformations, etc.. but still... not sure



06 June 2003, 06:17 PM
I hear it had something to do with Gimbal, but I could be wrong. When I was learning lightwave, I did a tutorial that had you make the extra hip bones, and that was their reason. Maybe different in this situation.

I had to use the extra hip in animan, cause it wouldn't setup up the foot controls without it... Did you have that problem?


06 June 2003, 07:51 PM
It's most likely used for better skin deformation after skinning the surface to the skeleton. The skin weighting would be minimal when rigging this way i think.

:: Galactor ::

06 June 2003, 08:05 PM
I helps in calculating the ik solving. I have noticed when rigging in Lightwave that the ik often was gitery until I set one angle of rotation per joint. I have seen good experiments with 3 bones in a hip done by Spline God. It may have to do with calculating ik through the gible points in rotation. I suspect that is so. Its why I started using 2 joints. in my own rigs in LW.

In maya it isnt needed.

06 June 2003, 08:45 PM
I used to use it to rotate the hips in the Y axis with out breaking up the skeleton in 2 different pieces. Now I use a script so its no longer neded. That dam mel language. :drool:

06 June 2003, 10:20 PM

As far as I know, its only real purpose if for better skin deformation. I dont think it has any other purpose and it definitely should'nt be animated :shame:


06 June 2003, 01:32 PM
yeah, I usually add them in simply because my skin defs come out that bit better but I dont touch them otherwise.

I do a similar technique between the back and collar bone except I do actually animate these joints allowing me to create collar bone movement and rotation esp. when a character does things like lift his arms above his head and push his arms out forward. The chest and shoulders both come into action on these movements and these two joints help greatly in getting that extra movement.

I did see some tutorial online a while back that showed how to use those extra joints in the hips to create some nice hip movement but damned if I can find it. :shrug:


Matt Leishman
06 June 2003, 04:05 PM
i think richard is right, in maya its not needed. good deformations can be achieved relatively easily without having to stick extra joints in your rig that are only going to potentially cause confusion for animators in the long run. Whether you are creatively painting skin weights, or using influence objects, you'll be better off in the long run - my 2 cents at least.

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