Ik help

C

chibisuke

0
Ik help

i have looked at the other treads on here that mention Ik, joints etc but i don't understand them very well. I'm a beginner at using cheetah

is there a simplfied tutorial out there that teaches you how to add Ik to a character
 
Hi chibisuke,
There's an IK tutorial in the help that comes with C3D, it's not an indepth tutorial but it is a good start.

Hope this helps.

Andrew
 
In the help, look in the tutorials section, there should be a link to an online tutorial (character animation). Plus there's the example alien that comes with C3D, I think it's in the examples folder.

Andrew
 
i figured out how to put the joints on the skeleton but how do i get the ik constraints to work

also i added the joints to my bear, but when i move the neck joint the whole body moves instead of just the head how do i change it?
 

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You built the spine the wrong way, it should start at the hips and go up.

I'm writing a little tutorial on setting up a rig but it won't be done for a while...

Basically, select the end joint of a chain (like an arm) an add the IK tag. Then you'll be able to pose the chain via IK (but you'll be keying rotations). You can click on the IK tag in the Object browser and add a target and a pole, that will let you use real IK. Poles only work with the 2D IK option, which is what I recommend that you use.

Make sure the joint chain has a slight bend (like at the elbow) before you add the IK tag or the solver will get confused as to how the joint should bend. You don't want a straight chain.
 
yeah, i figured out i started the wrong way after the post so i got that part now.

but after that i have trouble with the poseing of the character, it does funny things

also how do i use target and poles, what are they?

i'll have a picture up of how far i managed to get
 
What kind of trouble? You can post the jas if you want.

The IK target controls the end of the joint chain, you animate them to control your characters arms, say. The poles control how the chain faces. For example, for an arm the target will control the position of the wrist and the pole will control where the elbow is.
 
i want to post the jas file but how do i compress it down to the file size limit.

the problem i has was when i bend the bear, it doesn't bend properly.

could show me an example in how to add a target and pole
 

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Looks like you need to have a look at your weighting too, you're getting a bad fold on the upper chest.

Andrew

P.S. As for the funny things, that just might be how you've weighted the mesh and the joints your trying to transform (rotate).
 
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i made this bear quickly in maya to use as practice to do joint setup in cheetah would that cause some problems
 
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Hi.
500kb as a zip file? That is strange. Andrew´s walk cycle just take 130kb zipped.
Maybe have a look in the preferences->Import/Export->jas and check "binary" and try again.

Frank
 
i created a simple person in cheetah and added joints to it and it work. i did the same thing to the bear but then it didn't

i have the file attached (not the bear) i can't get the joints to move the right way when i try to bend the knee
 

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  • joints.zip
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Bend the joints before you attach the IK targets. You don't need to go over board, just slightly rotate them in the direction you anticipate them to rotate in after you've IK tagged them. Just check over the IK section in the help to confirm this. If after you've add the IK Handle with a target and you find the joints are flipping when you over extend the IK target then add a pole.

Thanks

Andrew
 
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