Character Rig Help

chaselt

Hey everyone!

I'm working on a project that requires me to rig a character for pretty much the first time. So this may or may not be a beginner/noob question . I'm currently at the end of the skinning phase of things and am running into a few problems.

My main issue right now is fixing some unsightly folding of typology when I bend certain limbs. I'm not sure if this is something I need to be handling exclusively through skin weights or the way I have been going about, using the Shape Editor and creating corrective blend shapes that I then key to the respective axes on their specified control.

Here is what I mean.

So here is a Z only rotation ~90 degrees with just skin weights.


And it is with the corrective blend shape.


This all works fine. But I see complications when adding multiple degrees of rotation at once.

For instance...

Here is the leg rotated on Y ~90 with a corrective blend shape.


So when I then rotate the leg in Z 90 degrees with the leg already rotated in Y 90 degrees it looks like this...


Both blend shapes triggering and causing a mess.

All of this is to ask what I'm missing here.

Is this something that I can only solve through skin weights, am I missing something when it comes to blend shapes, or do I have to do something else entirely?

Any help is much appreciated!

KielFiggins

You've hit a very common issue.  Try researching 'pose space deformers' and it'll show you how to setup multiple blendshapes
https://knowledge.autodesk.com/support/maya/learn-explore/caas/CloudHelp/cloudhelp/2016/ENU/Maya/files/GUID-00699C13-8CA1-450C-937D-57C7B3DFD8C6-htm.html

kaspersp

There are more ways of reaching one pose, so this will always be a problem for you. The best you can do is to anticipate most possible ways of reaching a pose and deal with all of them. 

BraveRabbits weightDriver has helped me deal with this issue on multiple occasions (http://www.braverabbit.com/weightdriver/). 

chaselt

@KielFiggins - Thanks for the feedback! I'll look more into pose space deformers, hopefully that solves my problem.

@kaspersp - That looks like a super useful tool, thanks for the share! It seems like it comes close to solving my problem. But from what I understand, weightDriver is a position based solution which would work fine if I only needed one blendshape in that position but I think I would need two (possibly more?).

One with the foot facing facing up.

And one with the foot facing inward.

kaspersp

Another solution could be to drive your blendshape using quaternions. They are a bit more forgiving. 

Blond

Your screenshots remind me of this video series I've seen years ago.
Have you seen them? It might help.

https://www.youtube.com/watch?v=vwU6aAi3mtc


But, yeh, you have a very common issue. I usually get the same when I try to fix the wrist roll deformation on my character's forearm.

Anyway, the most simple trick I would do to solve this be to base my solution on a Translation/ Distance method over a Rotation based method. Eulerian rotation are always bound to mess up at one point.



Basically, place and constraint a Locator on your character's foot . Then make that locator the main driver of your blend shapes using set driven keys. Whenever the Locators reaches a certain height and distance form its origin (X, Y and Z value), activate the blend shapes.

chaselt

@Blond -  Yeah, those videos actually got me a decent ways to solving this haha.

I'm liking your Translation/Distance solution! I've been messing with using the rotations of locators to drive my shapes. However, I think what you are saying is the way to go seeing as I am already hitting some problems using rotation.

Thank you for the suggestion!