Blender Principled BSDF

Updated August 29, 2018

Principled BSDF Node is Blender's PBR ubershader for Blender Cycles Renderer. You probably want to use this for pretty much everything.

Inputs

Some notes on the inputs and what kinds of values to give them.

Subsurface

Used for subsurface scattering (things that have an eggshell or milky translucent surface).

Metallic (Metalness)

Almost always either 0 or 1. Real materials are either metal or dielectric, and very rarely anything in-between.

Metalness maps let you define the metalness levels for a material with a texture, as you would for a normal or bump maps.

Specular

Leave it at 0.5 for dielectric materials. It is tuned for an object with refraction at an index of 1.5, which is the majority of dielectric materials.

Typically, if you want low specular, you actually want high roughness, not low specular.

From the Blender manual:

To compute this value for a realistic material with a known index of refraction, you may use this special case of the Fresnel formula: specular=((ior−1)/(ior+1))2/0.08

  • water: ior = 1.33, specular = 0.25
  • glass: ior = 1.5, specular = 0.5
  • diamond: ior = 2.417, specular = 2.15

Specular Tint

It's rare that you want to mess with this. Dielectric materials don't have tinted reflections.

Roughness

The roughness of the material.

Anisotropic

Rarely needed. Twisting and rotation of reflections. Like the type of reflection you would see on the back of a frying pan. Some particular objects have this type of reflection, but otherwise, leave alone.

You would use a tangent to control the direction the anisotropic goes.

Sheen and Sheen Tint

Rarely used. Useful for fabric. Pretty much only fabric. Similar to a velvet shader.

Clear Coat

Like the clear coat on car paint. Typically used on a roughed metallic or varnished wood.

IOR + Transmission

IOR and Transmission are linked. Transmission only works if metallic is set to 0. IOR and Transmission together allow for glass.

Example

Example table from Blender Manual (licensed CC-BY-SA):

A table showing how BSDF inputs act together

Resources

3d concepts, Blender