TY - JOUR AU - Neumann, L AU - Neumann, A AU - Szirmay-Kalos, László TI - Reflectance models with fast importance sampling JF - COMPUTER GRAPHICS FORUM J2 - COMPUT GRAPH FORUM VL - 18 PY - 1999 IS - 4 SP - 249 EP - 265 PG - 17 SN - 0167-7055 DO - 10.1111/1467-8659.00378 UR - https://m2.mtmt.hu/api/publication/2612466 ID - 2612466 AB - We introduce a physically plausible mathematical model for a large class of BRDFs. The new model is as simple as the well-known Phong model, but eliminates its disadvantages. It gives a good visual approximation for many practical materials: coated metals, plastics, ceramics, retro-reflective paints, anisotropic and retro-reflective materials, etc. Because of its illustrative properties it can be used easily in most commercial software and because of its low computational cost it is practical for virtual reality. The model is based on a special basic BRDF definition, which meets the requirements of reciprocity and of energy conservation. Then a class of BRDFs is constructed from this basic BRDF with different ent weight functions, The definition of such weight functions requires the user to specify the profile of the highlights,from which the weight function is obtained by derivation. It is also demonstrated how importance sampling can be used with the new BRDFs. LA - English DB - MTMT ER -