PxrDisney BRDF overview

- So let's take a look at this PxrDisney BRDF.…We've used it a number of times in movies…throughout the course so far,…but let's take a look at a bit of the historical context…of why did this PxrDisney BRDF come to be in production,…because there certainly was a lot…of different models out there.…So why a new BRDF?…There's lots of existing BRDFs already…for diffuse and specular.…For diffuse, Lambert is the accepted norm out there,…and Lambert is Lambertian diffuse,…so that's like a full diffused surface,…like chalk or something like that,…it doesn't have any roughness.…

And on the specular side,…we've got a lot of different options.…Ashikhmin-Shirley is a specular model.…Beckman Anisotropic,…anisotropic we've used for metals.…And, as you can tell, these are all named after people,…hence the interesting and creative names.…But there was an industry need for BRDF…with these sets of features that we're going to talk about,…and these sets of features brought together some studies…and a paper at Disney, and thus a new BRDF.…