brows shape animation

[jamination]

I am trying to make eyebrows like the Animation Mentor rigs. The rig has 3 controls for each brow and I for the middle. It looks like each brow is hooked up to a min and max shape (my best guess). When all 3 brow controls for each shape are max down, the brow creates a nice straight line. My question is how would one achieve that while dealing with 3 separate shapes. Is it possible to create a shape (say the inner brow) max down, then work on the middle brow max down, and see the accummulative result as you are making the 2nd shape, and as you make the 3rd max shape (outer brow) see the result of the first 2 as you make that. Or is there just a better way to do this.

thanks
Phil

[3DMastermind]

I hear these rigs are reserved to AM applicants.
I don't know how you got it. Perhaps you attended?
I didn't understand your explanation.
Since you can not distribute it or risk having a scud go off in your neighborhood.
If you can show a screen capture or video of the controls in the area....
I'll let you know.

[franky]

i was in the first AM class.
the way the rigs work is not much special, but nicely executed. the whole face is shape driven and i replicated this techniques in a number of rigs here. no magic here and no copyrights. what AM is protecting is their characters, how they look, not particular the rigs.

its like you said, you got 3 controls hovering over the brow.
the right and left one you can move up/down/left/right. the middle one only up/down... this gives you all the control you need. for each maximum you create a shape key and link it to the position of the control. that's it... its simple and effective. even someone who doesn't know how to model can create these kind of shapes because they are so much limited in the area they influence.

[adamwozniak]

ive used stretchy bones in max before to do eyebrows. might not be the best way but ill throw it in as an alternative. on the plus side it saves setting up different shapes and you can move them however you want...so can be handy if your in a hurry

make a 1 bone chain. make a square null and match all transforms to the effector. position constrain the effector to the null. put a direction constraint on the root or the bone, and make it aim at the null. open up the expression editor on the length property of the bone and put this in:

ctr_dist( root., null.)

(you can measure the distance from root to effector but it will moan.) you can then make chains in the same way with a null inbetween each bone.

im not sure on the etiquette for rigging muscles in xsi, but i've used this method in max for bulky shoulders and problem areas etc.