I have been doing 3d graphics for a long time now. Its all about that little triangle. How many and how to use a texture or not. Just to make it take as little process power as possible. Effective use of spaces to separate groups of objects and now days how to make download as small as possible. Then there are some more things to think about like shadows, ambient occlusion and what kind of shaders that the viewer software uses. Reusing objects and textures are important. Trying to cut frame rates on the graphics card and making the build a nice experience for the viewer.
I see some great builds in games and in Second life that sometimes blow my mind. How did they do that? When I analyze it. It´s always really good use of triangles, space and texture. That is what I want to do. That is what 3D graphics is all about.