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.
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),…
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…