V-Ray Car Paint Material Parameters
Search keywords: layered material, car paint, shellac, blend, skin
The VRayCarPaintMtl material is a material that simulates a metallic car paint. It is a complex material with four layers: a base diffuse layer, a base glossy layer, metallic flakes layer, and clear coat layer. The material allows the adjustment of each of these layers separately.
Base color - the diffuse color for the base layer.
Base reflection - the reflectivity of the base layer. The reflection color itself is the same as the Base color.
Base glossiness - reflection glossiness for the base layer.
Flake color - the color of the metal flakes.
Flake glossiness - the glossiness of the metal flakes. It is not recommended to set this above 0.9 as it may produce artifacts.
Flake orientation - controls the orientation of the flakes relative to the surface normal. When this is 0.0, all flakes are perfectly aligned with the surface. When it is 1.0, the flakes are rotated completely randomly with respect to the normal. Values above 0.5 are not recommended as they can produce artifacts.
Flake density - the density (number of flakes) for a certain area. Lower values produce less flakes and higher values produce more flakes. Set this to 0.0 to produce a material without flakes.
Flake scale - scales the entire flake structure.
Flake size - the size of the flakes relative to the distance between them. Higher values produce bigger flakes and lower values produce smaller flakes.
Flake map size - internally the material creates several bitmaps to store the generated flakes. This parameter determines the size of the bitmaps. Lower values reduce RAM usage, but may produce noticeable tiling in the flake structure. Higher values require more RAM, but tiling is reduced. Be careful when using the Directional filtering method, as it may quickly take up gigabytes of RAM for larger map sizes. See the Examples section for a demonstration of the effect of this parameter.
Flake filtering - determines the way the flakes are filtered. Filtering is extremely important to reduce the work required to produce a clean image. See the Examples section for a demonstration of this parameter. The possible values are:
Simple - this method is faster and uses less RAM but is less accurate. It averages the orientation of the flakes together, which may alter the appearance of the material when viewed from a distance.
Directional - this method is slightly slower and uses more RAM but is more accurate. It groups the flakes based on their orientation before performing the filtering, so that the material appearance is preserved.
Flake seed - the random seed for the flakes. Changing this produces different flake patterns.
Flake mapping type - specifies the method for mapping the flakes. The possible values are:
Explicit UVW channel - the flakes are mapped using the specified channel.
Triplanar from Object XYZ - the material automatically computes mapping coordinates in object space based on the surface normals.
Flake UVW - the mapping channel for the flakes when the Flake mapping type is set to Explicit UVW channel.
Flake trace reflections - when off, the flakes will only produce specular highlights, but no actual reflections will be traced.
Coat color - the color of the coat layer.
Coat strength - the strength of the coat reflections when the surface is viewed directly from the front.
Coat glossiness - glossiness of the coat reflections.
Coat bump - this option allows you to select a texture for the bump or normal map of the coat layer
Coat bump amount - a multiplier for the Coat bump map
Coat bump type - this determines how the Coat Bump parameter is interpreted.
Trace reflections - when disabled, reflections from the different layers are not traced (they will only produce specular highlights).
Double sided - when enabled, the material is double-sided.
Subdivs - determines the amount of samples for the glossy reflections of the different layers.
Cutoff threshold - cutoff threshold for the reflections of the different layers.
The Material ID group is described here