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ronnie
12-18-2003, 08:09 PM
I'm smooth skinning a human and have trouble around the upper leg hip area. Any ideas?

john_homer
12-18-2003, 10:06 PM
thats a pretty broard question...
I guess I could only suggest placing your joints in the right place, and weighting it correctly...

some people use a corrective blendshape.. but I dont like to drive things off joints with more than 1 degree of rotation (like an elbow)... it a but unreliable...

you can use a "push - pull" joint to move the surface "up" rather than rotating into the surface (as joints do).

a push-pull joint is hard to explain..
create a joint on the surface of your mesh at the hip.
point constrain (with offset) to the knee joint (or a locator half way down, this is better), then break connections on the new joints tx and tz, so it only gets the ty movement
new as the knee comes up, the joint rises... it will move depending on the local translate axis (which it gets from its parent)... you will need to play with the position of the new joint AND the locator to get the result you want..

remember the direction is relative to the locator rotating around its parent (the hip joint)

good luck
.j

...also,
you might want to go with more descriptive subjects for your posts...
"rigging" in the "chracter setup" section doesn't say a lot...

verbal007
12-19-2003, 03:38 AM
john_homer, is this what you're talking about?
http://www.systemshutdown.com/foryou/cgtalk/pushPullJoint.jpg
Had to try it out... although a pretty darn sloppy job of recreating it.

Pretty neat trick... although eventually the joint makes it's way to the chest area. Maybe I misunderstood and got this wrong? In any case... still fun to play with.

- Jeremy

john_homer
12-24-2003, 11:51 PM
Originally posted by verbal007
john_homer, is this what you're talking about?
http://www.systemshutdown.com/foryou/cgtalk/pushPullJoint.jpg
Had to try it out... although a pretty darn sloppy job of recreating it.

Pretty neat trick... although eventually the joint makes it's way to the chest area. Maybe I misunderstood and got this wrong? In any case... still fun to play with.

- Jeremy

looks like you are constraining to the kenn joint... right??
put a locator closer to the hip joint and parent it to the hip joint.. constrain to that, the pushPull joint will move less.. or alternativly you could just have less weighted influence an that joint...

SKD are difficult to drive... what are you gonna use?? a joint rotation?? good luck with that! as soon as you rotate the hip out (ie, riding a horse) everything changes... as i said only usefull for joints that can only rotate on 1 plane IMHO....

have fun
.j

verbal007
12-26-2003, 01:03 AM
Originally posted by john_homer
looks like you are constraining to the kenn joint... right??
put a locator closer to the hip joint and parent it to the hip joint.. constrain to that, the pushPull joint will move less.. or alternativly you could just have less weighted influence an that joint...


Ah... I think I see what you're sayin now. Yeah, that would work a little better... k... a LOT better.

SKD are difficult to drive... what are you gonna use?? a joint rotation?? good luck with that! as soon as you rotate the hip out (ie, riding a horse) everything changes... as i said only usefull for joints that can only rotate on 1 plane IMHO....

Not even going to try and challenge that till I have some time to sit down and find a solution... which sure seems difficult.

Oh... and Happy Holidays. :)

- J

Nenox
12-26-2003, 04:10 PM
I've been able to drive stuff for joints that move in more than one axis. But I have not driven it form the rotatations of that joint but from the translations of eg. a locator.

Example:

PointConstrain a locator between the armJoint and the elbowJoint. Drive 2 "armpit" shapes with eg. translateY and translateZ of the locator. Parent the locator to the the clavicleJoint (Locator needs to inherit the transforms of the upper body for it to work).

This is how i remember setting it up. Maybe this could be used in other situations??

Cheers,
Nenox.

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