tFar

In computer graphics, tFar is a parameter used to denote the far clipping distance of a camera's viewing frustum or the far limit along a ray in ray-based computations. It is commonly used together with tNear to bound the depth range that is considered for rendering or intersection tests.

In perspective projection, points are mapped to depth through the projection matrix, and tNear and tFar correspond to where the viewing ray intersects the near and far planes. The choice of tFar affects depth precision: a larger far plane expands the depth range but increases quantization error, while a smaller tFar improves precision at the expense of visible depth.

In ray tracing and ray marching, t denotes the parameter along a ray O + tD, and tFar sets the maximum distance to test for intersections. It is used to bound computations and to clip geometry or volumetric samples that lie beyond the intended scene depth.

Although terminology varies by API, tFar is generally related to the far plane and to the projection matrix; it is commonly paired with tNear as part of the depth range. It also appears in shader code and camera parameter structures as a means to control rendering depth and performance.