Vehicle Modeling Guidelines

For the purposes of supporting vehicles in the VTP software, we need a consistent set of modeling conventions so that all vehicles can be loaded and treated similarly.

1. Make the Body color Purple (diffuse material of 255, 0, 255).
   At runtime, this can then be replaced with the actual desired color.

2. Name the wheels precisely:
      "front_left"
      "front_right"
      "rear_left"
      "rear_right"
   This allows the VTP runtime to find them.

3. The model should be centered around the origin, but translated upward so that its wheels rest on the ground plane.

4. The model should point forward (away from the camera), which corresponds to the -Z axis in OpenGL/vtlib.