Terminology and conventions

This page summarizes terms and conventions found in the source code of appleseed.

Short URL to this page: http://appleseedhq.net/conventions

Ray Tracing or Raytracing?

We prefer the two word variant Ray Tracing and we try to stick to it. Similarly we spell Path Tracing rather than Pathtracing.

Forward (as in Forward Ray Tracing or Forward Path Tracing)

Light paths are followed in the direction of the light flow, i.e. rays are traced starting from the light sources and toward the camera.

Backward (as in Backward Ray Tracing or Backward Path Tracing)

Light paths are followed in the opposite direction of the light flow, i.e. rays are traced starting from the camera and toward the light sources.

Normalized Device Coordinates (NDC)

Coordinates in [0,1)^2 (note: closed on the left, open on the right) of a point in the plane of an image. The point (0,0) is located at the top-left corner of the image and the point (1,1) is located at the bottom-right corner.

Sample Space

For an image of dimensions width x height pixels, the set of real-valued points in [0,width) x [0,height).