[maya] adding outlines to a finished character

Bummer6

I finished a character of mine. It's rigged and it's got blendshapes for facial expressions and stuff. Problem is, I'd like to add outlines to the model to give it a more stylized look. I know about the method of duplicating a mesh and reversing the normals to get the effect of an outline, but with all the blendshapes and stuff, it's not that easy.

Here's what I tried:
I duplicated the mesh with the input connections to maintain the deformation from the skinning and the blendshapes
then I increased the size of the outline mesh by moving all the vertices along the Z normal and then reversed the normals.
So far so good! Everything seems to work as intended. All the blendshapes still work, all the skinning is intact...
Now I delete non-deformer history to clean things up, AAAAAAAAAND both the main mesh and the outline mesh tear themselves apart completely, making the entire scene unusable, and undoing does nothing.

I could just NOT delete the history, but something tells me that's just ignoring the underlying issue... 

Obscura

I don't know how much this helps you , but the outline effect is usually done through a post process effect in games.

Fingus

Does this need to exported to a game engine or will you do a render in Maya?
If it's a game engine you can do the invert-and-inflate trick through a shader, or a post effect like Obscura suggested. 
For Maya you could use something like a MentalRay Contour shader (if you're on 2017+ I assume Arnold has something similar), or simply use their old Toon Outline system if that is still in there.

Bummer6

I'm only going to render it in the maya viewport. The toon outline system worked okay, but it shows some weird errors sometimes... For now, it will work.

Bummer6

I thought the toon outline system in maya would work, but for whatever reason, the outline doesn't animate with the rest of the mesh. The outline simply stays in place while the rest of the mesh moves. This only happens with the "offset mesh" outline options, and not with the "paint effects" option, but the paint effects option looks pretty bad in my opinion, so I'd like to avoid using it. The weird thing is that if I just click different frames in the timeline (not clicking and dragging) the outline mesh follows the character mesh just fine... It's only when the animation is playing that the outline doesn't follow.