View Full Version : CDK Adjusting the Biped rig

11 November 2008, 02:06 PM

I've recently decided to spend some time learning the CDK included with XSI.
And so the wonderful character auto rig tools such as biped come into action.
I also managed to get hold of some temporary learning material.

Any case, if I rig a model from a guide I run into some stumbling blocks. I get a nice rig BUT with skew controls. Specifically I'm getting skew Chest Upperbody and Hip controls as in NOT 90 degrees aligned to the floor plane.

Similar problem with the arm effectors (cubes) illustrated above.
Somehow I've already spent a lot of time trying to fix this, but I cannot figure it out (yet) Specially the arm effectors, I cannot get the control cube to rotate, never mind setting it to a new default position.

So here I am asking if some kind soul might be able to throw a little light into this.
Even since I don't think I'd want to animate using the convenient biped at all, if the generated rig controls end up coming out all skew :argh:

11 November 2008, 05:22 PM
Um maybe it's all in the guides right?
Heck this is one painful bit of trying to bring a character to life.

11 November 2008, 07:20 PM
To "solve" the not Aligned Chest and Hip CTRLs you can make New CTRLS and place them on the exact same place (Match Translation) and then Parent or Constraint the old CTRLS to the new ones.

To get the Effector to rotate simply select it, press Ctrl+R to open the Kinematic Chain PPG and Uncheck:

Effector Rotation--- Affected By Last Bone

Beware that this is similar to having the Hand root POINT Constrainted to the Effector, the Hand will not rotate with the Arm Bone orientation forcing you to adjust it.

I prefer this way myself but it will lead you to Gimbal Lock faster that you might want since you now have to Rotate the Hand to compensate for it not getting the Father Rotations.

Of course that you also now have 2 ways to control the Hand, by rotating the Effector and by rotating the Hand Bone, so theres your Gimbal Lock problem solved :D

Hope it helped

11 November 2008, 08:29 PM
Thanks. I knew there'd be a way and no way I'd guess that.
Don't like the sound of the consequences though.
I think I'll be getting into the Zen of bulding a guide rig a while longer.

So far it's almost coming out the way I want. And the effectors are finally coming out straight.
Looks like not moving the spine guides solves the problem of the controls not being square.
So bit by bit and without much more cursing I think Biped is finally beginning to give the results I wanted. Phew.

And you it's all mostly due to the fact that it's not nice modeling characters with their palms facing down. Don't ask why..

02 February 2009, 03:55 PM

I think I got most problems solved here?
It looks like rotating the arm root before generating the biped rig somewhat works.
Except for the elbow control, but it looks like deleting it and creating a standard
chain up vector control to replace it gets everything sorted?

I know I'm getting a nice range of arm motion with biped customised this way.
Can't predict any gimbal locking or other bad consequences?

NOTE: All I'm trying here is to generate a biped rig with palms facing forward and
no skew or wonky controls :D

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02 February 2009, 03:55 PM
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