Do toon shaded meshes require less polys?

I was wondering, in a Borderlands type game and art style, if I have a character with (for example) 4000 polys, can I "get away" with using less polys if that character is toon shaded? Is there anything to keep in mind when building models for toon shades?

Thank you

 

If you plan to add an outline to your models, try to keep them quite low poly count, because it will double the amount: 4000 polys model + 4000 polys outline. Talking about the shading, it does't really matter, higher poly count will give you better, smoother overall silhouette.

 

Speaking on the outline specifically...it will double your poly count but it will also double your draw calls and make it unable to be batched, which may make it unsuitable for mobile. To get around this you can add the outline in your modeling app, which is actually quite easy. You duplicate your object. UV map all of the duplicates polys to a black area on the texture map. Reverse the objects normals to make it inside out then scale it up a bit until you see the outline the way you like it. Then just use a non-outlined toon shader. This will still double the poly count(though you could probably clean some of them up) but it can now be made to use one draw call and be batched.

Trying to use less poly though, I've seen an issue with the outline where there are gaps at the edges if the angles aren't smooth enough. For example, add Unity's outline toon shader to a cube. It doesn't look like an outline anymore but instead like there are black planes floating behind the cube faces. This would probably only be a problem in extremely low poly models.

Other shaders may do the corners differently to avoid this problem and this may all be moot anyways if not using the outline.