Acceleration
- fewer rays
- Generalized rays
- faster intersections
Acceleration Structures
- Bounding boxes (possibly hierarchical)
- if no intersection with bounding box, no need to check objects
- spatial hierarchies (Oct-trees, kd trees, BSP trees)
- Oct tree takes 3D space, cuts it along the center for each axis of a cube, to break it into 8 octants.
- Another acceleration structure is grid
- first go through first grid cell if no intersection
- check next cell
- etc