Pole Vector Following Elbow

Maya
1

hi there,

i am experimenting with arm setup..

i got one idea that if pole vectors follows the elbow joint and independent by itself too(so that we could use it as independent pole vector)..

it also should have attribute so that animator could either make it follow elbow.. or world..

i imagine it can be done by placing some locator at elbow and constraining it to wrist joint...

and it is also parent constrain with offset to pole vector ....( if you have done such thing u will figure out what i am saying)...

for now... i need inputs from you guys..

ps: i know how to setup knee/elbow without polevector.. but animators here love the pole vector...

thanks guys..

Sunny

2

I can uderstand what your thinking but the way you say it makes it sound like looped thinking.

QUOTE
to also should have attribute so that animator could either make it follow elbow.. or world..

i imagine it can be done by placing some locator at elbow and constraining it to wrist joint...

But thats would just be ultimately a polevector too, so what you kindof want then is a polevector thet fed from 2 sources.

No problem just connect the positions of the locvctors to blend node. And then use the blend variable to controll wich to choose (or you could blend the 2 in othere ways offcourse). However if i may stress out you will need a reversefoot rig where the contiorller and wrist placement is independenfrom the real influencing bones in DAG becasue DAG cant be cyclic and thus something parentted to a child can never affect its ancestors in any way (maya will isntantly either behave badly, crash or say no you canyt do this). Tough you can have a wrist elbow object that not part of the same hirearchy.

3

thanks jooja,

i was using orient constrain and point...

and i used blend node now..and removed orient constrained.. devloped my own method... and has grouped the polevector controler to itself... and used that empty group to follow the elbow..

thanks..

ps:meanwhile.. do anyone has a trick to add a pole vector.. without moving the intermidiate way...

what i do is place a locator..on elbow joint and move it back in corresponding axis and then create pole vector
(i don't wanna start new thread so i asked it in same thread)..

thanks..

4

Mel?

5

mel.. what...?

i am asking workflow..how to do that.

6

Idea is to use mel to make button that puts the polevector in place, in manner that makes your workflow the way YOU want it to be.

at simplest it could look like this

//select elbow and it will place a locator suitably
{
string $joint[],$child[];
float $pos[],$pos2[],$mult;
$mult=2;
$joint=ls -sl -tl 1;
$child=listRelatives -children -type joint $joint[0];
$locator=spaceLocator;
$pos= xform -q -t -ws $joint[0];
$pos2=xform -q -t -ws $child[0];
xform -ws -t ($mult*$pos[0]-$pos2[0]) ($mult*$pos[1]-$pos2[1]) ($mult*$pos[2]-$pos2[2]);
}

but you might wantto piak the place manualy by clicking so you ay want

7

thanks jooja..

you get me to know of spaceLocator i didn't knew that command..

i am looking at script.. and will let you know the final result..

8

i think some vector mathhs is involved..
can you explain me how did you find that

this is point locator needs to be at

($mult*$pos[0]-$pos2[0]) ($mult*$pos[1]-$pos2[1]) ($mult*$pos[2]-$pos2[2]);

i think i am poor in vector maths too...

and how u find the multi to be 2...

9

QUOTE(sunny chopra @ 07/23/06, 07:20 PM) [snapback]243135/snapback ($mult*$pos[1]-$pos2[1]) ($mult*$pos[2]-$pos2[2]);

Well ive cleanned the eqyuation a bit originaly i had intended to write

$pos+$mult*($pos-$pos2) wich is the elbowvector plus the inverse of vetor form there to wrist tims a arbitrary multipler

However i just was feeling a bit nasty and collapsed it a bit thats why i have a formula that looks a nit crazy. It was there to mask what i did so youd need to think for yourself