Stochastic Flakes

This page provides information on the Stochastic Flakes Node in V-Ray for Blender.

Overview

The Stochastic Flakes material 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 Car Paint, but uses less memory and avoids the tiling issues for these materials. The term stochastic means "using a random variable".

UI Path

||Node Editor|| > Add > BRDF > Stochastic Flakes

Node

Reflect Filter – Specifies the amount of reflection and the reflection color.

Parameters

Blend Max – Number of flakes per pixel below which only the smooth distribution is computed.

Blend Min –Number of flakes per pixel below which the smooth distribution is not computed and blended.

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

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

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

Enable Flakes – When enabled, the material simulates flakes scattered on the surface of the object. When disabled, the material simply renders the specified brdf type with the specified glossiness. For more details, please see the Enable Flakes example below.

Flake Scale – Allowsto scale the texture space. For mapping type Explicit UVW channel scale 1.0 is recommended. For Triplanar from Object XYZ mapping, num flakes number of flakes are distributed in each square unit in local object coordinates. In thiscase it is necessary to lower flake scale (0.05, 0.01 or less) and increase num flakes, depending on the object size, especially if squareartefacts are observed.

Hilight Glossiness – Controls the distribution of the flakes. Values close to 1.0 will make all flakes oriented along the surface, whereas lower values will randomize the normals of the flakes. For more details, please see the Hilight Glossiness example below.

Lightness – Controls the brightness variation for the flake colors when Random hue is enabled.

Map Channel – Specifies which map channel to use, when mapping type is set to Mapping Channel.

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 will use a triplanar mapping to create the flakes. This mode is useful for objects that don't have suitable UV mapping.

Num 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 num flakes is 46340. If you need more than 2 billion flakes, increase the flake scale parameter. For more details, please see the Number of Flakes example below.

Random Hue – Enables randomized hue for the flakes.

Random Lightness – Generates random saturation for each flake color.

Random Saturation – Generates random saturation for each flake color.

Saturation – Determines the variance in color strength used for the flake colors when Random saturation is disabled.

Subdivs – Controls the number of samples to use when calculating reflections. Note that this parameter is available for changing only when Use local subdivs is enabled in the Global DMC Settings.

Tex Subdivs – The subdivisions of a unit square in texture space. Increase it only if you observe square-like artifacts in zoomed regions.