#gamedev @gameart tip.

The most common mistake I see taught is that you must keep everything in quads (4 sided polygons).

This results in artists leaving a whole mess of edges in a model that actually don't need to be there at all.

Another manifestation of this thinking is that deformable characters must be organised into loops of quads.

However, most limbs only bend in specific places, and so again, the majority of that data does not contribute to the model at all.

I go into examples of layouts that allow for good deformation in my book- but the jist here is:

Interrogate every vert and edge and ask what it contributes.

Silhouette? Texture seams? Deformation? Vertex paint? What does it give you?

If the answer is nothing- kill it.

Here is an example where the first topology does something. Here, this character uses the red vertex channel in the shader to carve holes in the flesh, revealing chunks of zombie meat underneath.

It also uses the blue channel for things that make the zombie muddy and wet.

Having an even topology in that example allows the vertex paint to be applied evenly, and the density is high enough that player's attacks appear to carve away where they shoot and hack.

Mmmm.

Now see how having an uneven topology creates vertex paint that streaks and goes all over the place.

For environments, Vertex paint can be a brilliant way to create variations on repeating models such as walls and floor tiles.
Vertex paint can be used to layer on damage, peeling paint, dirt, wetness and even displace the mesh.

Therefore it is actually cheaper to have MORE polygons in the model, then storing a whole bunch of texture variations.

The down side is this doesn't work with level of detail meshes as the vertex colors are stored... amazingly...in the vertices.

Another reason to have more polygons in environment models is helping to curve textures without warping happening.

Note the checks on the left are wonky. The checks on the right flow more naturally.

Stay tuned for my book that covers all this stuff... but until then, drop me a few bucks in the shape of a KO-FI. http://www.ko-fi.com/dellak 

You don't actually need loops at all for a joint to deform well, you just need to ensure the bordering edges either side of the pivot keep the intended shape. Like so...

Here is another sin I see all the time- divisions along a gun barrel. Unless a character is gonna bend this, or it is going to become comically flaccid- you don't need them.