Specular Constant for Anisotropic BSDF

Note: For more information on the use of this model, you can view Parameters of Interpolation Enhancement.

When modeling anisotropic BSDF models, the measure does not allow you to make the difference between the diffuse /lambertian parts and the specular/gaussian parts. The model applies the color measured with the integrating sphere to the whole BRDF. The result is that the specular reflection is the same color as the diffuse part, which is often not the case in real situations. The specular constant model allows you to make the difference between the diffuse/lambertian parts and the specular/gaussian parts for anisotropic BSDF.

Note: As this new model is based on the separation between diffuse and specular data brought by incidence interpolation, you can only use it on surfaces for which you activate incidence interpolation.

Warning: The validity of the model relies on the accuracy of the specular/diffuse separation. Any flaw will cause calculation errors.

On the following example you can view a sphere with a colored reflection spectrum illumined by a white source.

Before, the specular highlight had the same spectrum as the diffuse part, both had the same color.

With the new model, the specular highlight is white and the diffuse part remains unchanged.