Adding new CAT bones creates unusual broken weighting

GorseMonster · Mar 2012

Hey guys,

I'm in the process of putting the final touches on a character rig in 3DS Max using CAT rigging. While I was originally going to do a simple eyebrow, eyelid and jaw bone setup, I find myself with a little extra time and want to do a couple of mouth bones for additional expressions.

However, whenever I add a new bone to the rig and add it to the skin modifier, it sends any vertices weighted to it flying miles upwards or backwards. All bones I added prior to rigging still work just fine. I've searched for the forums for a bit and found nobody else talking about this problem.

I've had a couple of friends inform me that they had no problem when adding new bones to a rig during the skin process, but they were using an older version of MAX. Is there any way I can fix this without returning to square one, or am I simply missing something out?

Pictures:
No weighting to bone

Weighting to bone

Thank you all for your help in advance.

poopipe · Mar 2012

its proably something to do with weird transforms - CAT was that bad in the early days of 2012 that i completely stopped using it.

you should be able to fix it by simply disabling/enabling always deform in skin when in the bind pose

monster · Mar 2012

You need to make sure your bind pose matches your reference frame. Change the slider time to 0, and make sure your are in your original bind pose before adding more bones.

Kidd Kosmonaut · Dec 2013

I am having this exact same problem with my custom rig. Unfortunately the initial bind pose is no longer available. But this is a custom rig as I mentioned, not a CAT rig, so does that still apply? If it does, is there any other work around that would allow me to include new bones into the rig and skin modifier and still get the weighting to behave appropriately?

monster · Dec 2013

If you lost the original bind pose you need to do a workaround.

1. Go to frame 0.
2. Match the bind pose as close as you can.
3. In Skin's Advanced Parameters save the ENV file.
4. Collapse the modifier stack. (Collapse not Delete)
5. Add a new Skin mod, and Add all the bones including new bones.
6. Load the ENV file and click Match By Name for the bone list.

That should work.

Adding new CAT bones creates unusual broken weighting

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