A mathematical function describing how light is transmitted through a surface. The Bidirectional Transmittance Distribution Function (BTDF) is part of the broader Bidirectional Scattering Distribution Function (BSDF), which was likely first defined in 1980 by Bartell, Dereniak, and Wolfe. The BSDF describes the way light is scattered by a surface, but it is often split into reflected and transmitted components. The BTDF focuses specifically on the transmitted component.
How BTDF Works
The BTDF models how light passes through a surface by considering two angles: one for the incoming (incident) ray and another for the outgoing (transmitted) ray at a specific point on the surface.
- Input Angles: The function takes two angles as inputs: the incident angle and the transmitted angle.
- Output: The BTDF calculates the proportion of light transmitted through the surface based on these angles.
Applications of BTDF
The BTDF is used in various fields, including computer graphics, optics, and material science, to simulate and analyze how light interacts with different surfaces.
- Computer Graphics: Used to create realistic rendering of materials like glass or translucent objects.
- Optics: Helps in designing lenses, filters, and other optical components.
- Material Science: Helps understand the optical properties of various materials.