Diffuse Shaders PDF Print E-mail
Written by Sergey Shlyaev   
Wednesday, 17 December 2014 20:13

Diffuse shaders for Vray

This page shows two new diffuse models and their comparison to standard Lambert diffuse.

 

Lambert is the usual diffuse model.


Lommel-Seeliger is another diffuse model. A quote from Arnold documentation:

The Lommel-Seeliger volumetric scattering BRDF is a simple BRDF predicting scattering from a dusty surface. Dusty surfaces scatter the reflected light in all directions toward grazing angles to the surface. The BRDF is:

brdf(wi,wo) = 1 / (N.wi)+(N.wo)

The Lommel-Seeliger function is essentially a "distillation" of the Hapke function that does not contain more complicated terms. It relies on the incidence and emergence angles alone. It ignores masking and shadowing.

The Lambert and Lommel-Seeliger functions represent end-members on a scale that ranges from an "icy-type" surface (Lambert) to a "lunar-type" surface (Lommel-Seeliger).

 

"Full moon" is a full model for a moon-like surface. Not a simplified version like Lommel-Seeliger.


Comparison renders. Click for hi-res.

3pics_half

 

More pics. Click for hi-res.

Lambert turntable HD video

 

Lommel-Seeliger turntable HD video

 

Full Moon turntable HD video

 

A closeup render. Notice how "full moon" produce more details under the wing.

Download

 

3d test models are from:

The Stanford 3D Scanning Repository

Last Updated on Friday, 02 January 2015 21:13