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trowzers
07-16-2008, 10:04 PM
I've been using Timothy Albee's book, "LightWave 3D (8) Character Animation," as a guide for rigging my model. I've built all my Bones as Skelegons in Modeler, taken everything into Layout and converted the Skelegons to Bones. Whenever I use the rotate tool and numeric inputs to adjust the rotation on any of the bones, my model jumps out of synch (alignment) with the Bones. Since the model and Bones are locked together, attempting to rotate the model back into its proper orientation fails, because the Bones move as well.

Has anyone had this problem? Does anyone have a solution to this problem?

I'm working in LightWave 7.5 on a Mac.

Thanks.

-Bill

toby
07-17-2008, 12:52 AM
Try 'resting' them ( select bones, press 'r' )

SplineGod
07-17-2008, 09:30 AM
Make sure you do so on frame 0 and with your rig in a rest pose.

trowzers
07-17-2008, 10:36 AM
Thanks, I've tried that. It had no effect. Any other suggestions?

-Bill

SplineGod
07-17-2008, 10:40 AM
Since Tim advocates strong use of weight maps I would guess that you dont have them all assigned properly.

trowzers
07-17-2008, 12:32 PM
Thank you Larry.

It was a weight map problem. For any students of Timothy Albee who run into this problem, here's what I did wrong. Instead of following Timothy's skelegon instructions to the letter, I assumed he had missed a step and gave all my Weight Maps the same names as my bones in the Skelegon Tree before importing everything into Layout. Don't do this. The automatic Weight Maps that were assigned, when I imported my model into Layout and converted my skelegons to bones, were the problem.

Thanks again Larry.

-Bill

Surrealist.
07-19-2008, 10:40 AM
Yeah. When you create all your skellegons and name them, the Bone weights tool will automatically create weightmap names for each skellegon. When you import the model and convert the skellegons the weightmaps are automatically assigned to the bones with the same names.

SplineGod
07-19-2008, 04:13 PM
Thank you Larry.

It was a weight map problem. For any students of Timothy Albee who run into this problem, here's what I did wrong. Instead of following Timothy's skelegon instructions to the letter, I assumed he had missed a step and gave all my Weight Maps the same names as my bones in the Skelegon Tree before importing everything into Layout. Don't do this. The automatic Weight Maps that were assigned, when I imported my model into Layout and converted my skelegons to bones, were the problem.

Thanks again Larry.

-Bill

My recommendation based on my experience is to
generially do the following.
1. Put the basic bones into the model
2. Rest them
3. Test the rig. Pose it in its most extreme poses you expect.
4. Notice where unwanted deformations are.
5. Use hold bones to try and fix most of the major issues.
6. Use weight maps as a last resort and keep them as simple as you can. For example all legs might get one weight map and the body gets another. All the leg bones can share the same weight map and the rest of the bones share the body weight map.

The reason I recommend doing it this way is twofold:
1. Bones are already deformers. Weight maps modify the 'natural' bone influence so it helps to understand how bones work first and see how the bones are influencing first before adding weight maps. Bones also have their own controls, like falloff, bone strength. rest length. etc etc

2. You can save yourself a lot of time by doing weight maps last because you may find that your rig works fine with bones only or that you only need very simple ones.
Its also harder to troubleshoot deformations the more things are stacked on each other. Hold bones can also be animated.