[Figures 15 & 16] When areas that have different geometric complexity run into each other, a transition will occur. These areas will require triangles to get the transition to work.

1. Try to avoid triangles. Sometimes reducing geometric complexity in a particular region will cause a transition to another, more detailed area. In cases like this, the low-resolution rows of polygons will run into higher-resolution rows of polygons. The transition has to be a series of triangles that get the two areas to smoothly flow into each other (Figures 15 and 16). This is an unavoidable circumstance, unless the polygonal model is not optimized at all after converting the model from NURBS surfaces. Certain problems will arise, however, if the model has too many triangles. Models that are all triangles are almost unusable for subdivision modeling techniques. Although triangles are sometimes a necessary evil, they should be avoided.

2. Try to maintain an even distribution of geometry if possible. There will be areas that will require fine detail, but the quadrangles on the cheek should maintain relatively the same size as the quadrangles on the top of the head. This will allow the textures to map more evenly to the geometry and will facilitate the use of subdivision modeling much easier than if there is a dramatic change in size between the polygons in different areas of the model.