CGTalk - Up vector question

shadowedge

11-28-2007, 10:06 AM

Hi everyone,

I made a 3 bone chain with an up vector constraint. The up vector is working fine, and so is the rest of the leg's chain. Unfortunately working with 3 bones posed a limitation I failed to anticipate.

http://i66.photobucket.com/albums/h273/ninjei/upvectorissue.jpg

I need to be able to move the encircled joints sideways so that I can pose the model in a "spiderman squat" like position. The work around Im thinking of right now is to recreate a 2 bone chain, and add a single bone as the 3rd. This way, I can move the up vector normally while being able to move the effector indipendently.

But I feel this is an impractical work around. Any suggestions?

Many thanks in advance!

J

Helli

11-28-2007, 11:26 AM

What sort of Character is this ? 3 bones for the leg is quite uncommon ? What you described as workaround would be the best way.

shadowedge

11-28-2007, 11:34 AM

Hi helli,

Actually these are the hind legs of a humanoid dragon. Like most quadrupeds the rear legs usually have 3 segments.

*sigh* I guess it was my bad for going with 3 bones :banghead:

How I wish I had Isner and Sim's XSI 4 book :drool:

Helli

11-28-2007, 01:18 PM

Ah okey. I am not too familar with thsi sort of anatomy but isn't the 3rd bone the foot ? The leg itself only has 2 bones.

shadowedge

11-29-2007, 12:54 AM

but isn't the 3rd bone the foot ? The leg itself only has 2 bones.

Yep you're right about that. I didn't give the leg structure enough thought when I started rigging. The third bone should actually be an extended heel, not a 3rd segment for the leg...

I lost a lot of sleep over this last night... Anyway, Back to work! :wip:

Thanks!

J

McNistor

12-09-2007, 10:43 AM

Hi

I see that is a "dog-leg" and it is the default one from XSI.
I have also a character that uses the dog-leg. I made my own rig as the default one didn't satisfy my needs.
I will comeback later and share the rig. Maybe you will learn smth from it or just see my rigging weakness :).

McNistor

12-09-2007, 11:20 AM

shadowedge

12-13-2007, 03:56 AM

You can download the scn file here (http://catalin.easyhosting.ro/DogLeg.rar).
It might not be apropriate for your model but it works perfect for mine which is a robot anyway.
I hope it will help you somehow.
You can also PM me if you want to talk about rigging and XSI in general... i'm sure we can learn a lot from eachother.
Good luck!

McNistor,

thanks! Yeah it did start out from the default dog leg rig, but I disected it into a new model. I really appreciate the help, perhaps I could keep your file for one of my upcomming models.. hehehe :thumbsup:

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