Imposters
Billboards or point sprites are quite often used as "imposters" pretending to be a 3D geometry by showing a 2D image that is always facing the camera.
Candera supports both, Billboards and Point Sprites to achieve three-dimensional impressions by showing camera aligned two-dimensional images.
In order to relief distinction between Billboards and Point Sprites see following comparison:
- Billboards support rectangular dimension and non-uniform scale.
- Billboards support different rotation techniques (see Alignment), whereas Point Sprites are always screen aligned.
- Point Sprites have a performance advantage due to less geometry (one instead of 4 vertices).
Overall recommendation: Use Point Sprites for spherical shapes like particles, lens flares, sparkles, dust which are screen aligned. \ Further, use Billboards for world up oriented clouds, text, or yaw axis aligned trees, and signs, etc.