i am trying to direction constrain the Biped.Head bone to a Null.
so when i move the null the head will look at it.

Since the Null is not exactly at the Root of the bone, i set to Compensate and then i did the Constrain.
but when i move the null around the head act very weird kinda like having bad dynamics on it.

(this doesn’t happen if the align axis is set to 1 or -1 in any of the X, Y,Z Axis)

any one got a similar problem like this?

thanks guys

A direction constraint with an offset won’t do the job, you should use a pose constraint, and in its option, unselect scaling and position, you should get what you want.

Thanks Sebas, for the tip.
the way you do it is similar of creating a shadow null of the bone and rotate it.

i want to put the null somewhere in space and the head loo at it.

(i need the character to look at the face of other people, and i prefer instead rotate and check if the head is looking at them, just put the null in their head.)

with your experience i know you are full of aces under your sleeve.

You can set it up like this, I guess:

Direction constrain the null to look at the biped head bone, then pose constrain the head bone to the null, and uncheck pos/scl like SebasProulx said.  This way you can control the twist of the head with the rotation of the null as well (which you will need to key to prevent it from potentially flipping).

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Tuna!
You the Man, very intelligent way to do it,
inverse the position of the constrains,
instead direct the head to the null,
the null to the head with the pose constrain of Sebas.

thanks, i will tryit right away =)
oh, also to take the time of doing the scene. help me a lot.

Wait, i’m not sure a got you question right in the first time.

A direction constraint should be fine? no need for an offset. 

If you put the alignt axis at -Y, the biped should look in the right direction, but you need an [B]upvector, [/B]that might be your problem. Put it on top of the head, child of the neck. Then, in the constaint property page, in the up-vector tab, set the affected axis as X.

I guess you are using xsi’s biped rig?