Using BRDF for radiance and luminance calculation

Correct representation of the phenomenon of reflection of visible radiation or thermal radiation is a necessary precondition for accurate modelling of luminous phenomena (visualization) and thermal phenomena (heat transfer). A full description of reflective properties of materials is included in BRDF1—difficult to apply in computer calculations. The article presents several BRDF models and for the most extended model (the one developed by Embrechts), a method of determination of optimum coefficients defining BRDF is proposed, based on empirical data. The article presents an example of visualization illustrating the effects of spread reflection, using the method presented.