This page provides information about the Car Paint material in V-Ray for Revit

 

Overview


The Car Paint material is a material that simulates a metallic car paint. It is a complex material with four layers: a base diffuse layer, a base bump layer, metallic flakes layer, and clear coat layer. The material allows the adjustment of each of these layers separately.

 

 

Parameters


Base

Some parameters are available only in Advanced mode.

Color – Specifies the diffuse color for the base layer.

Reflection – Specifies the reflectivity of the base layer. The reflection color itself is the same as the Base color.

Glossiness – Specifies reflection glossiness for the base layer.

Base Bump

Mode/ Map – Specifies the type of bump map or normal map to apply to the base layer if a map file is specified.

Bump Map – A height map should be used.
Normal Map in Tangent Space – RGB map should be used with this option. Uses tangents set to each individual face.

Amount – A multiplier for the bump/normal effect.

 


Flakes


Some parameters are available only in Advanced mode. 

Color – Specifies the color of the metal flakes.

Glossiness – Specifies the glossiness of the metal flakes. It is not recommended to set this above 0.9 as it may produce artifacts.

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. For more information, see The Flake Orientation Parameter example below.

Density – Controls the 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.  The Flake Density Parameter example below.

Scale – Controls the scale of the entire flake structure. For more information, see The Flake Scale Parameter example below.

Size – Controls the size of the flakes relative to the distance between them. Higher values produce bigger flakes and lower values produce smaller flakes. For more information, see  The Flake Size Parameter example  below.

Mapping/ UV– Specifies the method for mapping the flakes.

Mapping Channel – Flakes are mapped using the specified channel.
Triplanar – The material automatically computes mapping coordinates in object space based on the surface normals.

Filtering Mode – Determines the way the flakes are filtered. Filtering is extremely important to reduce the work required to produce a clean image.

Simple – 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 – 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.
For more information, see The Flake Filtering Parameter example below.

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. For more information, see Anti-aliasing Filters example below.

Seed – Sets the random seed for the flakes. Changing this produces different flake patterns.

 

 

 


Example: The Flake Orientation Parameter

 

This set of images demonstrate the effect of the Flake orientation parameter. Note how lower values produce flakes more aligned with the surface normal, so that light is reflected more uniformly. Higher values produce more random flakes leading to more variation in the flake illumination.

 

Flake orientation is 0.0

Flake orientation is 0.1

Flake orientation is 0.3

 

 


 

Example: The Flake Density Parameter

 

This set of images shows the effect of the Flake density parameter. Note how larger values produce more flakes, but do not change the flake size.

 

Flake density is 0.5

Flake density is 1.0

Flake density is 2.0

 

 



Example: The Flake Scale Parameter


This set of images demonstrate the effect of the Flake scale parameter. Note how lower values scale the entire flake structure.

 

Flake scale is 0.005

Flake scale is 0.01

Flake scale is 0.02

 

 


 

Example: The Flake Size Parameter


This set of images shows the effect of the Flake size parameter. Note how larger values make the individual flakes larger, but do not change their count.

 

Flake size is 0.5

Flake size is 1.0

Flake size is 2.0

 

 



Example: The Flake Filtering Parameter


This example shows the effect of the Flake filtering parameter.

 

No filtering and no anti-aliasing; the result is very noisy because of the small flake size.

No filtering, Adaptive DMC anti-aliasing. The result is accurate, but very slow since a lot of AA samples are required to anti-alias the flakes.

Flake filtering set to Simple, no anti-aliasing. The filtering greatly reduces the noise, but alters the appearance of the material.

Flake filtering set to Directional, no anti-aliasing. The noise is reduced and the material appearance is correctly preserved.

 

 


 

Example: Anti-aliasing Filters


Here is an example briefly demonstrating the effect of different anti-aliasing filters on the final result.

Note that rendering with a particular filter is not the same as rendering without a filter and then blurring the image in a post-processing program like Adobe Photoshop. Filters are applied on a sub-pixel level, over the individual sub-pixel samples. Therefore, applying the filter at render time produces a much more accurate and subtle result than applying it as a post effect. 

 

Simple filtering
 Flake map size is 256.
Flake maps take less than 1 MB.

Simple filtering
Flake map size is 1024.
Flake maps take 5 MB.

Simple filtering
Flake map size is 2048
Flake maps take 21 MB.

Directional filtering
Flake map size is 256.
Flake maps take 10 MB.

Directional filtering
Flake map size is 512.
Flake maps take 40 MB.

Directional filtering
Flake map size is 1024.
Flake maps take 161 MB.

Directional filtering
Flake map size
is 2048.
Flake maps take 645 MB.

 

 

Coat Parameters


Some parameters are available only in Advanced mode.

Color – Specifies the color of the coat layer.

Strength – Specifies the strength of the coat reflections when the surface is viewed directly from the front. 

Glossiness – Controls the glossiness of the coat reflections.

Coat Bump

Mode/Map – Specifies the type of bump map or normal map to apply to the coat layer if a map file is specified.

Bump Map 
Normal Map in Tangent Space

Amount – Multiplies the bump map effect. 

 

 

Reflection Options (All Layers)


This rollout is available only in Advanced mode.

Trace Depth – Specifies the maximum number of times a ray is reflected by the material. 

Cutoff Specifies a threshold below which reflections do not be traced. V-Ray tries to estimate the contribution of reflections to the image, and if it is below this threshold, these effects are not computed. Do not set this to 0.0 as it may cause excessively long render times in some cases.

Base Reflections – When disabled, the base layer only produces specular highlights, but no actual reflections are traced. 

Flake Reflections – When disabled, the flakes only produces specular highlights, but no actual reflections are traced. 

Coat Reflections – When disabled, the coat layer only produces specular highlights, but no actual reflections are traced. 

 

 

Multipliers


This rollout is available only in Advanced mode.

Mode – Specifies one of the following methods for adjusting textures.

Multiplier – Multipliers can be specified to adjust colors and textures.
Blend Amount – Blend amounts can be specified to adjust colors and textures.

Base Color – Controls the intensity of the diffuse color for the base layer.

Base Glossiness – Controls the intensity of the base layer's reflection glossiness.

Flake Color – Controls the intensity of the color for the metal flakes.

Flake Glossiness – Controls the intensity of the metal flake glossiness.

Coat Color – Controls the intensity of the coat layer color.

Coat Glossiness – Controls the intensity of the coat layer's glossiness.

Coat Strength – Controls the intensity of the coat reflections.

 

 



For all other material settings, see the Attributes section on Materials page.

 

Notes


  • The Car Paint material needs to precalculate several textures related to the flakes. Depending on the Flake map size parameter, this may take a few seconds. When working in the material editor, this may lead to slight delays between changing a parameter and the update of the material swatch