© Bertrand Benoit

Table of Contents

This page provides an overview of the VRayMtl and its parameters.




Overview

VRayMtl is a very versatile material that allows for better physically correct illumination (energy distribution) in the scene and more convenient reflection and refraction parameters. This material can be easily set up to simulate a huge variety of surfaces from plastics to metals, glass and more by adjusting a handful of parameters.

Furthermore, with VRayMtl you can apply different texture maps, control the reflections and refractions, add bump and normal maps, self illumination and translucency.




UI Paths

You can create a VRayMtl through the ||Content Browser|| > Add New > V-Ray > VRayMtl or from ||Content Browser|| > Add New > V-Ray > VRay Material Instance > Parent Material > VRayMtl.


||Content Browser|| > Add New > V-Ray > VRayMtl


||Content Browser|| > Add New > V-Ray > VRay Material Instance > Parent Material > VRayMtl















In order to select  VRayMtl as a Parent material you have to first make the plugin folder VRayForUnreal visible. Enable Show Engine Content and Show Plugin Content in the View Options of the Content Browser. Then the VRay Materials will be listed in the Parent dropdown menu.


When VRayMtl is assigned as a Parent and you want to create a solid material with no refractive, transparent or translucent properties, change the Blend Mode in the Material Property Overrides to Opaque.




For your materials to work properly at render time make sure your textures have a valid file path (Source File in the texture Details panel). V-Ray loads the textures from that directory during rendering. If the texture is not found at the specified location, V-Ray will automatically export the texture. You can then find it in your project folder > Content > Texture Cache.





VRayMtl Parameters

Diffuse


These are the diffuse properties of the material. Note the actual diffuse color of the surface also depends on the Reflection and Refraction colors.

  • DiffuseColor – Specifies the diffuse color of the material.
  • UseDiffuseSideColor –  Enables the use of side(fresnel) color and texture.
  • DiffuseSideColor – Specifies the side(fresnel) diffuse color of the material.
  • UseDiffuseTex – Enables the use of Texture for Diffuse.
  • DiffuseTexAmount – Specifies the blend amount between DiffuseTex and DiffuseColor.
  • DiffuseTex – Specifies the Diffuse Texture when UseDiffuseTex is enabled.
  • UseDiffuseSideTex – Enables the use of Texture for the side(fresnel).
  • DiffuseSideTex – Specifies the Diffuse side(fresnel)Texture when UseDiffuseSideTex is enabled.
  • DiffuseTex_Channel – Specifies the UV channel index for the DiffuseTex.
  • DiffuseTex_OffsetU – Specifies the horizontal offset of the DiffuseTex.
  • DiffuseTex_OffsetV – Specifies the vertical offset of the DiffuseTex.
  • DiffuseTex_TileU – Specifies the horizontal repetition of the DiffuseTex.
  • DiffuseTex_TileV – Specifies the vertical repetition of the DiffuseTex.
  • DiffuseTex_Triplanar – Enable triplanar mapping for the DiffuseTex.
  • DiffuseTex_TriplanarBlend – Specifies the blend amount between the different Texture projections. Lower values produce sharper transitions between projections.
  • DiffuseTex_TriplanarScale – Adjusts the scale of the DiffuseTex when DiffuseTex_Triplanar is enabled.

ReflectionColor=0,0,0; ReflectionGloss=1; FresnelIOR=1.6



 Reflection


 Specifies the reflection properties of the material.

  • ReflectionColor – Specifies the amount of reflection and the reflection color. Any value other than black enables reflection.
  • UseReflectionSideColor –  Enables the use of side(fresnel) reflection color and texture.
  • ReflectionSideColor – Specifies the side(fresnel) reflection color of the material.
  • UseReflectionTex – Enables the use of Texture for Reflection.
  • ReflectionTexAmount – Specifies the blend amount between ReflectionTex and ReflectionColor.
  • ReflectionTex – Specifies the Reflection Texture when UseReflectionTex is enabled.
  • UseReflectionSideTex – Enables the use of Texture for the side(fresnel).
  • ReflectionSideTex – Specifies the Reflection side(fresnel)Texture when UseReflectionSideTex is enabled.
  • ReflectionTex_Channel – Specifies the UV channel index for the ReflectionTex.
  • ReflectionTex_OffsetU – Specifies the horizontal offset of the ReflectionTex.
  • ReflectionTex_OffsetV – Specifies the vertical offset of the ReflectionTex.
  • ReflectionTex_TileU – Specifies the horizontal repetition of the ReflectionTex.
  • ReflectionTex_TileV – Specifies the vertical repetition of the ReflectionTex.
  • ReflectionTex_Triplanar – Enables triplanar mapping for the ReflectionTex.
  • ReflectionTex_TriplanarBlend – Specifies the blend amount between the different Texture projections. Lower values produce sharper transitions between projections.
  • ReflectionTex_TriplanarScale – Adjusts the scale of the ReflectionTex when ReflectionTex_Triplanar is enabled.


DiffuseColor=0,0,0;  ReflectionGloss=1; FresnelIOR=1.6



FresneIOR


Specifies the Index of Reflection for Fresnel calculations of the material.

  • FresnelIOR – Specifies the IOR to use when calculating Fresnel reflections.
  • UseFresnelSide –  Enables the use of side(fresnel) values and texture.
  • FresnelSide – Specifies the side(fresnel) value of the material.
  • UseFresnelIORTex – Enables the use of Texture for Fresnel IOR.
  • FresnelIORTexAmount – Specifies the blend amount between FresnelIORTex and FresnelIOR.
  • FresnelIORTex – Specifies the Fresnel IOR Texture when UseFresnelIORTex is enabled.
  • UseFresnelSideTex – Enables the use of Texture for the side(fresnel).
  • FresnelIORSideTex – Specifies the Fresnel side(fresnel)Texture when UseFresnelSideTex is enabled.
  • FresnelIORTex_Channel – Specifies the UV channel index for the FresnelIORTex.
  • FresnelIORTex_OffsetU – Specifies the horizontal offset of the FresnelIORTex.
  • FresnelIORTex_OffsetV – Specifies the vertical offset of the FresnelIORTex.
  • FresnelIORTex_TileU – Specifies the horizontal repetition of the FresnelIORTex.
  • FresnelIORTex_TileV – Specifies the vertical repetition of the FresnelIORTex.
  • FresnelIORTex_Triplanar – Enable triplanar mapping for the FresnelIORTex.
  • FresnelIORTex_TriplanarBlend – Specifies the blend amount between the different Texture projections. Lower values produce sharper transitions between projections.
  • FresnelIORTex_TriplanarScale – Adjusts the scale of the FresnelIORTex when FresnelIORTex_Triplanar is enabled.


DiffuseColor=0,0,0;  ReflectionColor=1,1,1; ReflectionGloss=1



ReflectionGloss


Controls how blurry, or glossy, the reflections of the material will be.

  • ReflectionGloss – Controls the sharpness of reflections. A value of 1.0 means perfect mirror-like reflection; lower values produce blurry, or glossy, reflections. 

  • UseReflectionGlossSide –  Enables the use of side(fresnel) value and texture.
  • ReflectionGlossSide – Specifies the side(fresnel) value of the material.

  • UseReflectionGlossTex – Enables the use of Texture for Reflection Gloss.

  • ReflectionGlossTexAmount – Specifies the blend amount between ReflectionGlossTex and ReflectionGloss.

  • ReflectionGlossTex – Specifies the Reflection Gloss Texture when UseReflectionGlossTex is enabled.

  • UseRefrlectionGlossSideTex – Enables the use of Texture for the side(fresnel).
  • ReflectionGlossSideTex – Specifies the Reflection Gloss side(fresnel)Texture when UseReflectionGlossSideTex is enabled.

  • ReflectionGlossTex_Channel – Specifies the  UV channel index for the ReflectionGlossTex.

  • ReflectionGlossTex_OffsetU – Specifies the horizontal offset of the ReflectionGlossTex.

  • ReflectionGlossTex_OffsetV – Specifies the vertical offset of the ReflectionGlossTex.

  • ReflectionGlossTex_TileU – Specifies the horizontal repetition of the ReflectionGlossTex.

  • ReflectionGlossTex_TileV – Specifies the vertical repetition of the ReflectionGlossTex.

  • ReflectionGlossTex_Triplanar – Enable triplanar mapping for the ReflectionGlossTex.

  • ReflectionGlossTex_TriplanarBlend – Specifies the blend amount between the different Texture projections. Lower values produce sharper transitions between projections.

  • ReflectionGlossTex_TriplanarScale – Adjusts the scale of the ReflectionGlossTex when ReflectionGlossTex_Triplanar is enabled.

DiffuseColor=0,0,0;  ReflectionColor=1,1,1; FresnelIOR=1.6



Refraction


Specifies the refractive properties to the material. Note that the actual refraction color depends on the Reflection color as well.

  • Refraction – Specifies the amount of refraction and the refraction color. Any value other than black enables refraction.

  • UseRefractionSideColor –  Enables the use of side(fresnel) refraction color and texture.
  • RefractionSideColor – Specifies the side(fresnel) refraction color of the material.

  • IOR – Specifies the index of refraction for the material, which describes the way light bends when crossing the material surface. A value of 1.0 means the light will not change direction.

  • UseRefractionTex – Enables the use of Texture for refraction.

  • RefractionGloss – Controls the sharpness of refractions. A value of 1.0 means perfect glass-like refraction; lower values produce blurry or glossy refractions.

  • RefractionTex – Specifies the refractionTexture when UseRefractionTex is enabled.

  • UseRefractionSideTex – Enables the use of Texture for the side(fresnel).
  • RefractionSideTex – Specifies the Refraction side(fresnel)Texture when UseRefractionSideTex is enabled.

  • RefractionTex_Channel – Specifies the UV channel index for the RefractionTex.

  • RefractionTex_OffsetU – Specifies the horizontal offset of the RefractionTex.

  • RefractionTex_OffsetV – Specifies the vertical offset of the RefractionTex.

  • RefractionTex_TileU – Specifies the horizontal repetition of the RefractionTex.

  • RefractionTex_TileV – Specifies the vertical repetition of the RefractionTex.

  • RefractionTex_Triplanar – Enables triplanar mapping for the RefractionTex.

  • RefractionTex_TriplanarBlend – Specifies the blend amount between the different Texture projections. Lower values produce sharper transitions between projections.

  • RefractionTex_TriplanarScale – Adjusts the scale of the RefractionTex when RefractionTex_Triplanar is enabled.

ReflectionColor=1,1,1; ReflectionGloss=1; FresnelIOR=1.6

To use it you must also set the Blend Mode in the Material Property Overrides to Alpha Composite.



BumpTex


Specifies the bump properties to the material.

  • UseBumpTex – Enables the use of Texture for Bump.

  • BumpTexAmount – Specifies the bump amount.

  • BumpTex – Specifies the Bump Texture when UseBumpTex is enabled.

  • UseBumpSideTex –  Enables the use of side(fresnel) texture.
  • BumpSideTex – Specifies the bump side(fresnel)Texture when UseBumpSideTex is enabled.

  • BumpTex_Channel – Specifies the UV channel index for the BumpTex.

  • BumpTex_OffsetU – Specifies the horizontal offset of the BumpTex.

  • BumpTex_OffsetV – Specifies the vertical offset of the BumpTex.

  • BumpTex_TileU – Specifies the horizontal repetition of the BumpTex.

  • BumpTex_TileV – Specifies the vertical repetition of the BumpTex.

  • BumpTex_Triplanar – Enables triplanar mapping for the BumpTex.

  • BumpTex_TriplanarBlend – Specifies the blend amount between the different Texture projections. Lower values produce sharper transitions between projections.

  • BumpTex_TriplanarScale – Adjusts the scale of the BumpTex when BumpTex_Triplanar is enabled.



DiffuseColor= 1,1,1; ReflectionColor=0,0,0;  ReflectionGloss=1; FresnelIOR=1.6



NormalTex


Specifies a normal bump map to be used with the material and the bump properties for the normal map.

  • UseNormalTex – Enables the use of Texture for Bump.

  • NormalTexAmount – Specifies the normal bump amount.

  • NormalTex – Specifies the Normal Texture when UseNormalTex is enabled.

  • UseNormalSideTex –  Enables the use of side(fresnel) texture.
  • NormalSideTex – Specifies the Normal side(fresnel)Texture when UseNormalSideTex is enabled.

  • NormalTex_Channel – Specifies the UV channel index for the NormalTex.

  • NormalTex_OffsetU – Specifies the horizontal offset of the NormalTex.

  • NormalTex_OffsetV – Specifies the vertical offset of the NormalTex.

  • NormalTex_TileU – Specifies the horizontal repetition of the NormalTex.

  • NormalTex_TileV – Specifies the vertical repetition of the NormalTex.

  • NormalTex_Triplanar – Enables triplanar mapping for the NormalTex.

  • NormalTex_TriplanarBlend – Specifies the blend amount between the different Texture projections. Lower values produce sharper transitions between projections.

  • NormalTex_TriplanarScale – Adjusts the scale of the NormalTex when NormalTex_Triplanar is enabled.


DiffuseColor= 1,1,1; ReflectionColor=1,1,1;  ReflectionGloss=1; FresnelIOR=1.6



Selfillumination


Specifies the emissive properties of the material.

  • SelfIlluminationColor – Controls the emission of the surface. Any value other than black enables self-illumination.

  • UseSelfIlluminationSideColor –  Enables the use of side(fresnel) color and texture.
  • SelfIlluminationSideColor – Specifies the side(fresnel) selfillumination color of the material.
  • SelfIlluminationMult – Specifies a multiplier for the self-illumination effect.

  • UseSelfIlluminationTex – Enables the use of Texture for Selfilllumination.

  • SelfIlluminationTexAmount – Specifies the blend amount between SelfIlluminationTex and SelfIlluminationColor.

  • SelfIlluminationTex – Specifies the SelfIllumination Texture when UseSelfIlluminationTex is enabled.

  • UseSelfIlluminationSideTex – Enables the use of Texture for the side(fresnel).
  • SelfIlluminationSideTex – Specifies the SelfIllumination side(fresnel)Texture when UseSelfIlluminationSideTex is enabled.

  • SelfIlluminationTex_Channel – Specifies the UV channel index for the SelfIlluminationTex.

  • SelfIlluminationTex_OffsetU – Specifies the horizontal offset of the SelfIlluminationTex.

  • SelfIlluminationTex_OffsetV – Specifies the vertical offset of the SelfIlluminationTex.

  • SelfIlluminationTex_TileU – Specifies the horizontal repetition of the SelfIlluminationTex.

  • SelfIlluminationTex_TileV – Specifies the vertical repetition of the SelfIlluminationTex.

  • SelfIlluminationTex_Triplanar – Enables triplanar mapping for the SelfIlluminationTex.

  • SelfIlluminationTex_TriplanarBlend – Specifies the blend amount between the different Texture projections. Lower values produce sharper transitions between projections.

  • SelfIlluminationTex_TriplanarScale – Adjusts the scale of the SelfIlluminationTex when SelfIlluminationTex_Triplanar is enabled.


DiffuseColor=0,0,0;  ReflectionColor=0,0,0

We suggest when using SelfIllumination to set the Blend Mode in the Material Property Overrides to Opaque.



Opacity


Specifies the opacity of the material.

  • Opacity – Specifies the amount of opacity. Any value below 1.0 makes the object transparent.

  • UseOpacitySide –  Enables the use of side(fresnel) value and texture.
  • OpacitySide – Specifies the side(fresnel) opavity value of the material.

  • UseOpacityTex – Enables the use of Texture for Opacity.

  • OpacityTexAmount – Specifies the blend amount between OpacityTex and Opacity.

  • OpacityTex – Specifies the OpacityTexture when UseOpacityTex is enabled.

  • UseOpacitySideTex – Enables the use of Texture for the side(fresnel).
  • OpacitySideTex – Specifies the Opacity side(fresnel)Texture when UseOpacitySideTex is enabled.

  • OpacityTex_AlphaFromIntensity – When enabled, opacity will be set from the RGB intensity of the OpacityTex. When disabled, opacity will be set from the alpha channel of the OpacityTex.

  • OpacityTex_Channel – Specifies the UV channel index for the OpacityTex.

  • OpacityTex_OffsetU – Specifies the horizontal offset of the OpacityTex.

  • OpacityTex_OffsetV – Specifies the vertical offset of the OpacityTex.

  • OpacityTex_TileU – Specifies the horizontal repetition of the OpacityTex.

  • OpacityTex_TileV – Specifies the vertical repetition of the OpacityTex.

  • OpacityTex_Triplanar – Enables triplanar mapping for the OpacityTex.

  • OpacityTex_TriplanarBlend – Specifies the blend amount between the different Texture projections. Lower values produce sharper transitions between projections.

  • OpacityTex_TriplanarScale – Adjusts the scale of the OpacityTex when OpacityTex_Triplanar is enabled.


DiffuseColor=1,1,1; ReflectionColor=0,0,0

To use it you must also set the Blend Mode in the Material Property Overrides to Translucent or Alpha Composite. Due to Unreal Engine's limitation when using Translucent blending mode and Two Sided enabled, back faces on two-sided geometry may appear front. To resolve this when using Opacity Tex uncheck the Two Sided option.



ClearCoat


Adds a layer on top the material with reflection and bump properties.

  • EnableClearCoat – Enables the Clear Coat layer.

  • ClearCoatStrength – Specifies the strength of the Clear Coat layer.

  • ClearCoatGlossiness – Controls the sharpness of reflections of the Clear Coat layer. A value of 1.0 means perfect mirror-like reflection; lower values produce blurry, or glossy, reflections.

  • UseClearCoatBumpTex – Enables the use of Texture for Bump of the Clear Coat layer.

  • ClearCoatBumpTexAmount – Specifies the bump amount of the Clear Coat layer.

  • ClearCoatBumpTex – Specifies the Bump Texture for Clear Coat layer when UseClearCoatBumpTex is enabled.

  • UseClearCoatBumpSideTex –  Enables the use of side(fresnel) texture.
  • ClearCoatBumpSideTex – Specifies the Clear Coat side(fresnel)Texture when UseClearCoatBumpSideTex is enabled.

  • ClearCoatBumpTex_Channel – Specifies the UV channel index for the ClearCoatBumpTex.

  • ClearCoatBumpTex_OffsetU – Specifies the horizontal offset of the ClearCoatBumpTex.

  • ClearCoatBumpTex_OffsetV – Specifies the vertical offset of the ClearCoatBumpTex.

  • ClearCoatBumpTex_TileU – Specifies the horizontal repetition of the ClearCoatBumpTex.

  • ClearCoatBumpTex_TileV – Specifies the vertical repetition of the ClearCoatBumpTex.

  • ClearCoatBumpTex_Triplanar – Enables triplanar mapping for the ClearCoatBumpTex.

  • ClearCoatBumpTex_TriplanarBlend – Specifies the blend amount between the different Texture projections. Lower values produce sharper transitions between projections.

  • ClearCoatBumpTex_TriplanarScale – Adjusts the scale of the ClearCoatBumpTex when ClearCoatBumpTex_Triplanar is enabled.


DiffuseColor= 0,0,0; ReflectionColor=1,1,1;  ReflectionGloss=0.6; FresnelIOR=1.6

To use it you must set the Shading Model in the Material Property Overrides to Clear Coat.



VRay2SidedMtl


Specifies if the material can transmit light on its back side.

  • Translucency – Specifies the amount of light being transmitted on the backside of objects. Values other than black will result in translucency.



To use it you must set the Shading Model in the Material Property Overrides to Two Sided Foliage.