Rigging Help Needed

#1

Hey everybody,

While working on my first rig in maya i’ve encountered a strange problem. I have a model of a cat which I’m trying to get to walk. The joints and skin weights are done, then I started adding the IK handles. The first three legs work fine, but when I add one to the last leg two of the joints move. Deleting the history of the joints doesn’t work and when I delete the history of the mesh it ‘unbinds’ the mesh and the joints. What should I do to stop this from happening?

Also, when I try to add controllers to the joints and I parented them, it deletes the connection between the joint and the previous one. Am I forgetting something?

All help will be very appreciated!!

P.S. English isn’t my main language so I’m sorry for any errors :smiley:

#2

Hello Adyll-NL,

It’s hard to tell why your joints are moving without seeing the rig, but first off are all your joints zeroed out correctly?

It’s possible that setting the prefered angle could fix this, I’ve had some strange joint problems in recent versions of maya when this wasn’t set.

If you parent your joints to your controls they wont be parented to the joint chain anymore. For FK joints you can either constrain them to the control, or you can add a shape node to the joints with the -s flag in the parent command. For example, create a joint and a nurbs circle which I’ll assume are called joint1 and nurbsCircle1. Now type in

parent -r -s nurbsCircleShape1 joint1;

which will parent the shape node of the nurbs circle to the joint so you can use the circle to select the joint.

Cheers,

Richard

#3

Hey Richard,

Thanks for the fast and usefull response, as I said this is my firs rig so I didn’t get everything you were talking about. I think you are right about the fact that the movement in the joints is caused by previous transform actions. But do you mean that I should freeze the transformations of the joints because for some reason that won’t work. Or do you mean something else entirely?

I did get the controllers to work (hurray) but because of the transformation hisory of the joints,
the controllers are moved as well when I linked them using the script editor.

Thanks for the tips and for your time!

Bart

#4

Hello Bart,

By zeroed out correctly, I meant are all your joints rotation values set to 0 0 0? If they are not, you can freeze them, but then you will need to align them correctly using Skeleton->Orient Joint.

If you have already skinned your mesh and don’t want to start again, look up cometSaveWeights.mel and use it to save all your skin weights. If you start freezing joints on a skinned mesh it will mess up your geometry.

When you use the parent -s command, it will move your curve over to align with the joint, which is probably why your controls are moving. If you simply want a circle control and you’ve aligned you joints so X points down the joint, create a nurbsCircle and rotate it 90 in the Z and then freeze it. Now it is world aligned on the Y,Z plane so X is up. Using the parent command now will move your control circle to the joint and line it up better.

Strange, but after replying to your post the other day, I had joints move on me while creating IK. Setting the prefered angle fixed it my end.

Richard

#5

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