The importance of metalness and why we’ve added the Metalness parameter to the V-Ray standard material to better support a PBR workflow in V-Ray Next.

Let’s set the record straight

The term “Physically Based Rendering” — or PBR — does, in itself, imply that the material definition used in PBR is based on real physics. Some have also interpreted this as meaning that other shading models are not based on real physics; which is wrong.

While real-time rendering shading models were not necessarily based on real physics, other ray tracers, such as V-Ray, have always been physically based. As such, PBR shading models became very popular for real-time rendering for two basic reasons:



It is actually physically based. It requires fewer variables — and therefore texture maps — to define a material.



Since memory resources are at a premium in the game industry, the PBR model has inevitably become very popular and very resourceful.

The main difference that the PBR shading model has over other physically based shading models, such as the one used by V-Ray, is how it describes reflections. Most people know this as the addition of a variable called “metalness”. If you look in most physics books, you will not see any description of a material by its “metalness. ” So, let’s examine a bit closer what this term means.

About metalness

There is, in fact, a distinction between two different types of materials: dielectric and conductive. Dielectric materials are insulators and conductive materials conduct electricity. Examples of dielectric materials include glass, plastic, wood, ceramic, leather and so on. Examples of conductive materials include steel, copper, gold — in other words: metals.