It’s important to decide carefully about where to remove polygons from the geometry. Remove the wrong ones, and the shape of our character will change dramatically. It could also result in bad deformation in the game.
The first two sorts of polygons you should consider for removal are unnecessary polygons and polygons that form shallow angles.
Your model is currently made up of hundreds of polygons, and almost all of them are needed. You may think that a polygon’s actual presence means it is necessary to a model, but this is not the case.
So how do you determine which polygons will be unused? An unnecessary polygon is one that does not add to the shape of the mesh, nor does it aid in its deformation.
Look at the two cubes in Figure 5.1. They look exactly the same; the only way they differ is in construction.