Introduction - If you have any usage issues, please Google them yourself
The Billboard sample illustrates the billboarding technique. Rather than
rendering complex 3D models (such as a high-polygon tree model),
billboarding renders a 2D image of the model and rotates it to always face
the eyepoint. This technique is commonly used to render trees, clouds,
smoke, explosions, and more. For more information, see
Common Techniques and Special Effects.