Computer Graphic Rendering of Material Surfaces

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Contents Introduction Goals & Description Project Results Project Personnel BRDF   NEFDS   OBL   Light Meter Rendering   Radiance   iBRDF Rendered Images & Data   NEFDS Images   NIST Images   Additional Images   NIST Data Source Code Links References

Oregon BRDF Library The Oregon BRDF Library (OBL) is a compilation of a wide range of BRDF functions constructed over the previous 30 years in the fields of physics and computer graphics. OBL offers a uniform, object oriented interface in C++ to this collection of BRDF functions, and is flexible enough to incorporate future BRDF models. The BRDFs included in OBL are: Lambertian Diffuse Model Minnaert Limb Darkening Model Blinn Cloud & Dusty Surface Model Cook-Torrance Specular Microfacet BRDF Oren-Nayar Diffuse Microfacet BRDF He-Torrance Comprehensive Analytic Model Ward Anisotropic Model Lafortune Generalized Cosine Lobe Model Beard-Maxwell Bidirectional Reflectance Model Phong Model Poulin-Fournier Anisotropic Model Arithmetic BRDF iBRDF A few of these BRDF models are shown below in Figures 3 and 4. Figure 3: Phong reflection model (left), Oren-Nayar Diffuse Microfacet BRDF (right).   Figure 4: Cook-Torrance Specular Microfacet BRDF (left), He-Torrance Comprehensive Analytic Model (right). Because of the uniform, object oriented C++ interface across all BRDFs, once a program is built for use with one BRDF model, substitution of any other is trivial. For this reason OBL has proven itself to be a useful and versatile tool. It has been used as the BRDF interface for a BRDF visualization system. A tool was created which determines the correspondence between the BRDF models of OBL and standard appearance scales. It has also been utilized extensively to provide the BRDF values for realistic image synthesis.

 

Measurement Science for Optical Reflectance and Scattering

Mathematical and Computational Sciences Division