View Full Version : how do i stop collaspes?

12 December 2008, 12:00 AM
I'm skinning a character and i'm trying to find a way, other than blendshapes, to fight collapsing joints and such.

At the moment, the biggest regions that would require such attention would be the elbows, knees, and stomach/mid torso.

I'm specfically interested in a sort of step-by-step tutorial, if there's one avalible. If not, any information would be welcome.

12 December 2008, 12:39 AM
Skinning it seems will only get you so far on areas like knees, elbows, shoulders and hips. A corrective blendshape is still the best bet or use a influence object like a muscle or the like to have the skin slide around.

There should be plenty of corrective blendshape tutorials on this forum or on the web. The trick is to not use a blendshape node for every single blendshape. Make one blendshape node and just add additional shape targets. So you have one node with 30 shapes instead of 30 nodes with one shape each.

12 December 2008, 02:13 AM
right, i knew that about blendshapes. I'm trying to figure out how to do influence objects.

Thanks though, this is a step in the right direction.

12 December 2008, 03:05 PM
To add an influence object, you need to have your mesh skinned.

Then, just simply select the influence object(s) and your skinned mesh and in the menu system go to skin -> edit smooth skin -> add influence (options box). I would personally add their influence with a value of 0 into the set so that you can better control the effect they have on your mesh, but then you'll need to go into your paint weights tool and paint the influence individually for each object (and unless you can write/find a script you won't be able to mirror influence objects).

It's a long process, and many professional TDs that I've talked to (including the author of Art of Rigging) say that they prefer to use corrective blendshapes/Pose Space Deformers. You can download a script to help out with this from Micheal Comet's website (can't remember it off the top of my head).

Good luck!

12 December 2008, 07:23 PM
thanks for the info! I have all 3 art of rigging books, i re-read them last night and found the chapters on muscle rigs, in theory, they should be exactly what i want/need.

i of course still need to get my character skinned, and UVed. I should probably do the UVs now before i get too far into rigging/skinning.

12 December 2008, 12:43 PM
(and unless you can write/find a script you won't be able to mirror influence objects).

True, but an easy workaround is this:
Mirror the object that you have as influenceobject
Add it as inf object, hold weights
Mirror skin weights

Might be helpful for someone ...

Ps. Im also preffering correcting blendshapes, much easier

// Otto

12 December 2008, 08:32 PM
blendshapes are a huge pain to mirror though, every time i've tried them, i've spent more time trying to get that right than anything else.

12 December 2008, 05:45 PM
They don't have to be symmetrical though, you can add a great deal of appeal to your facial expressions by having them hit the same target areas but still look different. Many times it helps to sell the "realism" of the character.

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12 December 2008, 05:45 PM
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