FRED Sources

FRED can accurately simulate virtually any light source to simulate the emission characteristics of an entity
(i.e., star, blackbody or thermal source) or device (i.e., LED, laser, arc lamp). Source power can be specified in photometric, radiometric or arbitrary units.


Each source can be mono-chromatic, or emit a range of wavelengths. FRED has built-in tools for setting wavelength weights, and can also synthesize a given color specified by Chromaticity coordinates, Tristimulus, or RGB values. Spectral distribution is simulated using Monte-Carlo probability techniques.

The user can define the following spectral distributions which may be applied to sources, and as a detector response function:

  • Gaussian
  • Black Body
  • Discretely sampled wavelengths

The user can create and trace as many sources as necessary, each with its own unique set of properties. 2D arrays are easily created using the 2D Array feature.

Source properties include:

  • Ray position (specified by grid, random planar/volume or points on a surface, bitmap, user-defined)
  • Ray direction (specified by direction vector(s), converging/diverging, angular range)
  • Location/orientation
  • Total power
  • Position apodization function (uniform, Gaussian, r, user-defined)
  • Direction apodization function (Lambertian, inverse Lambertian, rn, cosn, sinn sampled in spherical coordinates, user-defined)
  • Coherence state (incoherent or coherent)
  • Polarization state (unpolarized or polarized with specific ellipticity, handedness, and orientation)
  • Wavelengths (unlimited set of wavelengths, associated weights, and ray colors)
  • Immersion material
  • Post-construction propagation
  • Post-construction constant phase shift
  • Visualization (prior to raytracing/during raytracing)