Stochastic Flakes Mtl

The Stochastic Flakes Mtl node can be used to simulate car paints, snow, and other glittery materials. It works by simulating at render time the aggregated effect of a large number of mirror-like flakes scattered over the surface of an object. The material is somewhat similar to the V-Ray Flakes 2 Mtl and V-Ray Car Paint Mtl materials but uses less memory and avoids tiling issues for these materials. The term stochastic means "using a random variable".

This section lists input sockets that are not found in the Properties tab but only as inputs for the node.

Random Color Map – Available when the Colored Flakes parameter is set to Random from map. Specifies a texture from which random colors are sampled and applied to the flake color. Only the bottom-most horizontal row of pixels from the texture is sampled; all other parts are ignored. 

Colored Flakes – Determines whether the material uses colored flakes:

Off – No variance to the specified color of the flakes is applied.
Random hue – Enables randomized hue for the flakes.
Random from map – Enables the use of a texture map for randomized colors.

Enable Flakes – When enabled, the material simulates flakes scattered on the surface of the object. If disabled, the material renders the specified BRDF type with the specified glossiness.

Number of Flakes – The number of flakes, expressed as the square root of the actual number of flakes in the unit texture square. For example, a value of 3000 generates 9,000,000 flakes in the unit texture square. The number of flakes is restricted to 2³¹ (a little over 2 billion), which means the highest useful value for Number of Flakes is 46340. If you need more than 2 billion flakes, increase the Flake Scale parameter.

Hilight Glossiness – Controls the distribution of the flakes. Values close to 1.0 orient all flakes with normals pointing more perpendicular to the surface, whereas lower values randomize the normals of the flakes. An integer node can be connected to control this parameter. 

Blur Angle – Controls the "softening" of the flakes effect. Higher values produce softer results, while smaller values make the flakes sharper. Usually, values between 0.5 and 8 are used.

Reflect Filter – Specifies the reflection color of the flakes. A color node can be connected to control this parameter. 

Mapping Type – Specifies the way the flakes are scattered on the surface:

Mapping Channel – The flakes are mapped according to the specified mapping channel. The density of the flakes on the surface depends on the way the UVs follow the surface. 
Triplanar – The material uses triplanar mapping to create the flakes. This mode is useful for objects that don't have suitable UV mapping.

Map Channel – Specifies which map channel to use when Mapping Type is set to Mapping channel.

Flake Scale – Controls the scale of the texture space. When Mapping Type is set to Mapping channel, a value of 1.0 is recommended. For Triplanar mapping, the Number of Flakes amount is distributed in each square unit in local object coordinates. In this case it is necessary to lower the Flake Scale value to 0.05, 0.01, or even less, and increase the Number of Flakes value depending on the object size, especially if square artifacts are observed.

BRDF Type – Specifies the BRDF used to guide the distribution of the flakes:

GGX – Uses GGX distribution for the flakes (the GGX distribution has a longer "tail" compared to Beckmann).
Beckmann – Uses a Beckmann distribution for the flakes. 

Seed – The seed for the randomization of flakes. Changing this value produces different flake patterns.

Colored Flakes – Determines whether the material uses colored flakes:

Off – No variance to the specified color of the flakes is applied.
Random hue – Enables randomized hue for the flakes.
Random from map – Enables the use of a texture map for randomized colors. The map connected to the Random Color Map socket is used.

Saturation – Determines the saturation variation of the colors for all flakes.

Lightness – Controls the lightness variation of the colors for all flakes.

White Average – When enabled, renders colored flakes without the darkening effect. Note that this is not physically correct.

Blend Min – Specifies the number of flakes per pixel, below which the flakes are computed. When the number of flakes per pixel is above this value, the material gradually transitions into a smooth (non-discrete) BRDF.

Blend Max – Specifies the number of flakes per pixel, above which the material only computes a smooth (non-discrete) BRDF. If the number of flakes per pixel is below this value, the material gradually transitions into discrete flakes.