This page introduces you to the V-Ray Material, which is the major building block for most shading networks in V-Ray.

 

Page Contents

 

Overview


The V-Ray Material allows for better physically correct illumination (energy distribution) in the scene, faster rendering, and more convenient reflection and refraction parameters. Within the V-Ray Material, you can apply different texture maps, control reflections and refractions, add bump and displacement maps, force direct GI calculations, and choose the BRDF (highlight shape) for the material.

 


© Amello illustration



 

UI Paths:

|Shading viewport| > Shader Tree > Add Layer button > V-Ray Material

|Shading viewport| > Shader Tree > Add Layer button > V-Ray Materials > V-Ray Material

 

 

V-Ray Material Basic


Basic rollout





Create OpenGL viewport preview material – Creates a Modo material sourced from the current V-Ray material to be used for Modo's OpenGL viewport. The material captures the most important V-Ray Material features and is used for preview purposes only. The original V-Ray Material will be rendered in V-Ray production. In order to benefit from this feature and see the material properly in the viewport, you need to follow these steps: Set your viewport to Advanced mode and disable the Ray GL option, then in the 3D Viewport Properties > Drawing and Control tab set GL Background to Environment and GL Reflection to Same as GL Background. Then in Preferences > V-Ray Renderer > V-Ray In Modo renderer, turn off the Enable V-Ray materials in Modo renderer option.

Opacity Source – Assigns transparent properties to the material with one of two channels: Opacity Grayscale or Opacity Colored. Maps can be assigned to create a material that has a non-uniform opacity in the Shader tree with a vmtl Opacity colored or vmtl Opacity Grayscale for the effect. When a map is used, white is completely opaque and black is completely transparent. For more details, please see the Opacity example below.

Opacity Grayscale – Assigns transparent properties to the material with a monochromatic channel mixer color space. 1.0 is completely opaque and 0.0 is completely transparent.

Opacity Colored – Assigns transparent properties to the material with an individual color channel mixer. This enhances the import of .vrscene files coming from V-Ray for Maya.

Opacity Mode – Controls how the opacity map works.

Normal –  The opacity map is evaluated as normal: the surface lighting is computed and the ray is continued for the transparent effect. The opacity texture is filtered as normal.
Clip – The surface is shaded as either fully opaque or fully transparent depending on the value of the opacity map (i.e. without any randomness). This mode also disables the filtering of the opacity texture. This is the fastest mode, but it might increase flickering when rendering animations.
Stochastic – The surface is randomly shaded as either fully opaque or fully transparent so that on average it appears to be with the correct transparency. This mode reduces lighting calculations but might introduce some noise in areas where the opacity map has gray-scale values. The opacity texture is still filtered as normal.

Diffuse color – The color of the material. Note: The actual diffuse color of the surface also depends on the reflection and refraction colors.

Diffuse roughness – Used to simulate rough surfaces or surfaces covered with dust (for example, skin, or the surface of the Moon). For more details, please see the Diffuse Roughness example below.

Roughness Model Specifies the Roughness model.

Oren-Nayar A reflectivity model for diffuse reflection from rough surfaces that has been shown to accurately predict the appearance of a wide range of natural surfaces. We recommend using this roughness model.
Gamma-based  The roughness model used in previous versions of V-Ray. This is not the recommended option.

Self-Illumination – The self-illumination color of the material. A texture map can be used for the self-illumination color when placed in the Shader tree with a vmtl Self-Illumination color effect.

Self-Illumination affects GI – When enabled (default), the object's self-illumination adds light to the global illumination of the scene. When disabled, the object will not add light to the global illumination, which is not physically accurate behavior.

 

 


Example: Opacity

 

 

 


Opacity: 1.0 (default)

 


Opacity: Bercon Noise Map

 

 

 

 


Example: Diffuse Roughness

 

This example demonstrates the effect of the Diffuse Roughness parameter. Note how, as the Roughness increases, the materials appears more "flat" and dusty.

 

 


Roughness: 0.0
(regular diffuse material) 

 


Roughness: 0.5

 


Roughness: 1.0

 

 

Reflection Layer


 



BRDF Type – BRDF stands for Bidirectional Reflectance Distribution Function, an equation that defines how light is reflected off a surface. The BRDF Type determines the highlight's general shape and the look of its soft edges. For more details, please see the BRDF Type examples below.

PhongPhong highlight/reflections. 
Blinn
Blinn highlight/reflections. 
Ward
Ward highlight/reflections. 
GGX
 – GGX highlight/reflections.

GGX is the most modern and flexible BRDF type and is able to better represent a broad range of materials thanks to its ability to control the shape of the specular lobe.

There currently isn't any particular performance difference between models and there is little reason to choose any of the other types. 

 Read more...

Historically, the Phong, Blinn, Ward and GGX are successive reflectance models developed over the years in computer graphics where each model aimed to improve on the limitations of the previous ones. For example, the specular highlights with the Phong model have a very narrow and bright center with no falloff, but it doesn't work well with anisotropic reflections. The Blinn model has broader highlight center with a tight falloff. The Ward model has an even broader center and falloff. The GGX model has a bright center and an even longer falloff (at default settings). In the past, each model's characteristics resembled more closely a certain type of material, for example Phong could be used for plastics, Ward for cloth and metals, and Blinn for other common surfaces. However with the introduction of the GGX model, all of these surfaces can be approximated well, thus reducing the need for using the other models.

It should be noted that no principled model is able to represent all possible materials entirely accurately, and where those models fail - for example when the material isn’t viewed frontally - only approaches such as that of VRscans are able to capture the correct material representation. 

 

Reflection color – The reflection color. Note that the reflection color dims the diffuse surface color. For more details, please see the Reflection color examples below.

Reflection glossiness – Controls the sharpness of reflections. A value of 1.0 means perfect mirror-like reflection; lower values produce blurry or glossy reflections. For more details, please see the Reflection glossiness examples below. 

Hilight glossiness – Controls the sharpness of the highlight portion of the reflection. Normally this parameter is locked to the Reflection glossiness value in order to produce physically accurate results.

Lock hilight glossiness – When disabled, allows different values for the Hilight glossiness and Reflection glossiness, but this will not produce physically correct results.

Fresnel reflections – When enabled, makes the reflection strength dependent on the viewing angle of the surface. Some materials in real life (such as glass and water) reflect light differently at different viewing angles. Note that the Fresnel effect also depends on the Fresnel IOR value. For more details, please see the Fresnel options examples below.

Fresnel IOR – The Index of Refraction used when calculating Fresnel reflections. Normally this is locked to the Refraction IOR parameter, but you can unlock it for finer control.

Lock fresnel IOR – When disabled, unlocks the Fresnel IOR parameter for finer control over the reflections.

Reflection Subdivs – Controls the quality of glossy reflections. Lower values will render faster, but the result will be noisier. Higher values take longer but produce smoother results.

Note: In order to use the Reflection Subdivs parameter for glossy reflections, you need to enable the Use Local Subdivs option in the DMC Sampler. Otherwise, glossiness subdivs are controlled globally, which in most cases produces a good balance between render quality and performance.

Trace Reflections – When disabled, reflections will not be traced even if Reflection color is other than black. You can disable this option to produce only highlights. Note that when this option is disabled, the Diffuse color will not be dimmed by the Reflection color as would happen normally.

Max depth – The number of times a ray can be reflected. Scenes with many reflective and refractive surfaces might require higher values to look correct.

Exit color – If a ray reaches its maximum reflection depth (as set by the Max depth parameter), this color will be returned without tracing the ray further. Normally this is set to black.

Soften – Softens the edge of the BRDF at light/shadow transitions.

Enable dim distance – Enables the Dim distance parameter which stops tracing reflection rays after a certain distance.

Dim distance – Specifies a distance after which the reflection rays will not be traced.

Dim fall-off – The falloff radius for the dim distance.

Affect Channels – Specifies which channels are going to be affected by the reflectivity of the material.

Color only – The reflectivity will affect only the RGB channel of the final render.
Color+alpha – Causes the material to transmit the alpha of the reflected objects, instead of displaying an opaque alpha.
All channels – All channels and render elements will be affected by the reflectivity of the material.

Anisotropy(-1..1) – Determines the roundness of the highlight. A value of 0.0 means isotropic (round) highlights, while other values elongate the highlight. Negative and positive values simulate brushed metal surfaces. For more details, please see the Anisotropy examples below.

Anisotropy rotation – Determines the orientation of the anisotropic effect (elongation) as a value between 0 and 1 (where 0 is 0 degrees and 1 is 360 degrees).

UV Vectors Derivation – Controls how the direction for the anisotropic effect is chosen:

Local object axis – The direction is based on the Anisotropy Axis parameter.
Specified UVW generator
– The direction is based on the selected UVW generator.

Anisotropy Axis – Determines the direction of the anisotropic effect across the three possible axes.

 


 

Example: BRDF Type

 

In order to see this effect Reflection Glossiness must be lower than 1.0.

 


Type: Phong

 


Type: Blinn

 

 

 


Type: Ward

 


Type: Microfacet GTR (GGX)

 

 




 

Example: Reflection Color

 

This example demonstrates how the Reflect color parameter controls the reflectivity of the material. Note that this color also acts as a filter for the Diffuse color (e.g. stronger reflections dim the diffuse component).

 

 


Reflection Color: Black
(0, 0, 0) 

 


Reflection Color: Grey
(128, 128, 128)

 


Reflection Color: White
(240, 240, 240)

 

 


 


 

Example: Reflection Glossiness

 

 


Reflection Glossiness: 1.0

 


Reflection Glossiness: 0.8

 


Reflection Glossiness: 0.4

 

 

 

 


 

Example: Fresnel Option

 

This example demonstrates the effect of the Fresnel reflections option. Note how the strength of the reflection varies with the Fresnel IOR of the material. For this example, the Reflect color is white (240, 240, 240).

 

 


Fresnel reflections: Enabled
Fresnel IOR: 1.3

 


Fresnel reflections: Enabled
Fresnel IOR: 2.0

 


Fresnel reflections: Enabled
Fresnel IOR: 10.0

 


Fresnel reflections: Off

 

 

 

 


 

Example: Anisotropy

 

This example demonstrates the effect of the Anisotropy and Rotation parameters, which determines the shape of the highlight. For the examples below the Type was set to Microfacet GTR (GGX).

 

 


Anisotropy: 0.0, Rotation: 0.0
With all values set to 0 this gives isotropic highlights

 


Anisotropy: -0.5, Rotation: 80.0

 

 

 


Anisotropy: -0.5, Rotation: 160.0

 


Anisotropy: -0.8, Rotation: 0.0

 

 

 

 

Refraction Layer


 



Refraction color – The refraction color. Note that the actual refraction color depends on the reflection color as well. For more details, please see the Refraction color examples below.

Refraction IOR – 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. For more details, please see the Refraction IOR examples below.

Refraction glossiness – Controls the sharpness of refractions. A value of 1.0 means perfect glass–like refraction; lower values produce blurry or glossy refractions. For more details, please see the Refraction glossiness examples below.

Refraction Subdivs – Controls the quality of glossy refractions. Lower values will render faster, but the result will be noisier. Higher values take longer but produce smoother results.

Note: In order to use the Refraction Subdivs parameter for glossy refractions, you need to enable the Use Local Subdivs option in the DMC Sampler. Otherwise, glossiness subdivs are controlled globally, which in most cases produces a good balance between render quality and performance.

Trace refractions – Enables refractions for the current material.

Max depth – The number of times a ray can be refracted. Scenes with lots of refractive and reflective surfaces may require higher values to look correct. For more details, please see the Refraction Max depth examples below.

Use exit color – When enabled, and a ray has reached the maximum refraction depth (as set by Max depth), the ray will be terminated and the Exit Color value returned. When disabled, the ray will not be refracted but will be continued without changes.

Exit Color – If a ray has reached its maximum depth this color will be returned instead of tracing the ray further. For more details, please see the Refraction Exit Color examples below.

Affect alpha – Specifies which channels are going to be affected by the transparency of the material.

Color only – The transparency will affect only the RGB channel of the final render.
Color+alpha – Causes the material to transmit the alpha of the refracted objects, instead of displaying an opaque alpha.
All channels – All channels and render elements will be affected by the transparency of the material.

Affect shadows – This parameter will cause the material to cast transparent shadows to create a simple caustic effect dependent on the refraction color and the fog color. For accurate caustic calculations, disable this parameter and instead enable Caustics in the GI Render Settings. Simultaneous usage of both Caustics and Affects Shadows can be used for artistic purposes but will not produce a physically correct result.

Enable dispersion – When enabled, true light wavelength dispersion is calculated, as with the light effect through a prism.

Abberation – Increases or decreases the Dispersion effect. Lowering this value widens the dispersion. For more details, please see the Abberation examples below.

 


 

Example: Refraction Color

 

This example demonstrates the effect of the Refraction color parameter to produce glass materials. For the images in this example, the material has a gray Black color, white Reflection color, and the Fresnel Reflections option is enabled.

 

 


Refraction color: Black
(0, 0, 0)
No refraction is produced

 


Refraction color: Gray
(192, 192, 192)

 


Refraction color: White
(255, 255, 255)

 

 




 

Example: Refraction IOR

 

This example demonstrates the effect of the Refraction IOR parameter. Note how light bends more as the IOR deviates from 1.0. When the index of refraction (IOR) is 1.0, the render produces a transparent object. Note, however, that in the case of transparent objects, it might be better to assign an opacity map to the material rather than use refraction.

 

 


Refraction IOR: 0.8

 


Refraction IOR: 1.0

 


Refraction IOR: 1.3

 


Refraction IOR: 1.8

 

 

 



 

Example: Refraction Glossiness

 

This example demonstrates the effect of the Refraction glossiness parameter. Note how lower Refraction glossiness values blur the refractions and cause the material to appear as frosted glass.


 


Refraction glossiness: 1.0

 


Refraction glossiness: 0.9

 


Refraction glossiness: 0.8

 

 

 

 


 

Example: Refraction Depth

 

This example demonstrates the effect of the refraction Max depth parameter. Note how too low of a refraction depth produces incorrect results. Also, in the last two examples, note how areas with total internal reflection are also affected by the Reflection Max depth.

 

 


Refraction Max depth: 1.0
Reflection Max depth: 5.0

 


Refraction Max depth: 2.0
Reflection Max depth: 5.0

 


Refraction Max depth: 4.0
Reflection Max depth: 5.0

 


Refraction Max depth: 8.0
Reflection Max depth: 5.0

 


Refraction Max depth: 8.0
Reflection Max depth: 8.0

 

 

 

 


 

Example: Refraction Exit Color

 

This example demonstrates the effect of the refraction Exit color parameter. This is mostly useful to show areas of deep refractions in the image, or for materials needing higher refraction depth. Note how the red areas are reduced when the Reflection Max depth and Refraction Max depth are increased.

 

 


Refraction Exit color: Off
Reflection Max depth: 5.0
Refraction Max depth: 5.0

 


Refraction Exit color: On, Red
(255, 0, 0)
Reflection Max depth: 2.0
Refraction Max depth: 2.0

 


Refraction Exit color: On, Red
(255, 0, 0)
Reflection Max depth: 5.0
Refraction Max depth: 5.0

 

 

 

 


 

Example: Abbe Number

 

 


Abbe Number: Disabled

 


Abbe Number: 10.0

 


Abbe Number: 40.0

 

 

 

V-Ray Material Advanced


Fog rollout


 




Fog color – The attenuation of light as it passes through the material. This option simulates the fact that thick objects look less transparent than thin objects. Note that the effect of the fog color depends on the absolute size of the objects and is therefore scene-dependent. This parameter can be mapped with a texture. It is recommended to use a 3D texture for the purpose. For more details, please see the Fog color examples below.

Absorption distance – Directly linked to the Fog multiplier. Its intention is to facilitate Modo users who are used to manipulating the corresponding parameter in native Modo material.

Fog multiplier – The strength of the fog effect. Smaller values reduce the effect of the fog, making the material more transparent. Larger values increase the fog effect, making the material more opaque. For more details, please see the Fog multiplier examples below.

Fog bias – Changes the way the fog color is applied. Negative values make the thin parts of the objects more transparent and the thicker parts more opaque and vice-versa (positive numbers make thinner parts more opaque and thicker parts more transparent).

Fog multiplier in centimeters – When enabled, the fog effect will be dependent on the system units.

 


 

Example: Fog Color

 

This example demonstrates the effect of the Fog color parameter. Notice how the thick areas of the object are darker in the two images on the right because of the light absorption of the fog.

 

 


Fog color: White
(255, 255, 255)
no light absorption

 


Fog color: Gray
(243, 243, 243)

 


Fog color: Green
(230, 243, 213)

 

 

 

 


 

Example: Fog Multiplier

 

This example demonstrates the effect of the Fog multiplier parameter. Smaller values cause less light absorption because of the fog; while higher values increase the absorption effect.

 

 


Fog multiplier: 0.3

 


Fog multiplier: 1.0

 


Fog multiplier: 1.5

 

 

 

Translucency (SSS)


 


Translucency type – Selects the algorithm for calculating translucency (also called sub–surface scattering). Note that refraction must be enabled for this effect to be visible (Refraction color set to a color other than black). Currently, only single-bounce scattering is supported. The possible values are:

None – No translucency is calculated for the material.
Hard (wax) model – Specifically suited for hard materials like marble.
Soft (water) model – Suitable for soft materials like liquids.
Hybrid model – The most realistic SSS model. Suitable for simulating skin, milk, fruit juice and other translucent materials.

Translucency color – Normally the color of the sub–surface scattering effect depends on the Fog color; this parameter adds tint to the SSS effect.

Light multiplier – A multiplier for the translucent effect.

Scatter direction – Controls the direction of scattering for a ray. A value of 0.0 means a ray can only go forward (away from the surface, inside the object); 0.5 means that a ray has an equal chance of going forward or backward; 1.0 means a ray will be scattered backward (towards the surface, to the outside of the object).

Scatter coefficient – The amount of scattering inside the object. A value of 0.0 means rays will be scattered in all directions; 1.0 means a ray cannot change its direction inside the sub–surface volume.

Maximum Thickness – Limits the rays that will be traced below the surface. This option is useful if you don't want or need to trace the whole sub–surface volume.

 

Options


 


 


Double-sided – When enabled, V-Ray will flip the normals for back-facing surfaces with this material assigned. Otherwise, the lighting on the "outer" side of the material will be computed always. This option could be used to achieve a fake translucent effect for thin objects.

Note: For the best results, it is recommended that you use the V-Ray 2-Sided Material instead of this parameter when possible. 

Reflect on back side – When disabled, V-Ray will calculate reflections for the front side of objects only. Enabling this option will make V-Ray calculate the reflections for the back sides of objects as well.

Glossy rays as GI – Specifies on what occasions glossy rays will be treated as GI rays:

Never – Glossy rays are never treated as GI rays.
GI rays only – (Default) Glossy rays will be treated as GI rays only when GI is being evaluated. This can speed up rendering of scenes with glossy reflections.
Always – Glossy rays are always treated as GI rays. A side effect is that the Secondary GI engine will be used for glossy rays. For example, if the primary engine is irradiance map and the secondary is light cache, the glossy rays will use light cache (which is a lot faster).

Cutoff – A threshold below which reflections/refractions will not be traced. V-Ray tries to estimate the contribution of reflections/refractions 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.

Use irradiance map – When enabled, the irradiance map will be used to approximate diffuse indirect illumination for the material. If disabled, Brute Force GI will be used in which case the quality of the Brute force GI is determined by the Subdivs parameter of the Irradiance Map. This can be used for objects in the scene which have small details that are not approximated very well by the irradiance map.

Energy preservation – Determines how the diffuse, reflection, and refraction color affect each other. V-Ray tries to keep the total amount of light reflected off a surface to less than or equal to the light falling on the surface (as in the real life). For this purpose, the following rule is applied: the reflection level dims the diffuse and refraction levels (a pure white reflection will remove any diffuse and refraction effects), and the refraction level dims the diffuse level (a pure white refraction color will remove any diffuse effects). This parameter determines whether the dimming happens separately for the RGB components or is based on the intensity:

Color – Causes dimming to be performed separately on the RGB components. For example, a pure white diffuse color and pure red reflection color will yield a surface with a cyan diffuse color (because the red component is already taken by the reflection).
Monochrome – Causes dimming to be performed based on the intensity of the diffuse/reflection/refraction levels.

Fix dark edges – When enabled, fixes the dark edges that sometimes appear on objects with glossy materials.

Glossy Fresnel – When enabled, uses glossy fresnel to interpolate glossy reflections and refractions. It takes the Fresnel equation into account for each "microfacet" of the glossy reflections, rather than just the angle between the viewing ray and the surface normal. The most apparent effect is less brightening of the grazing edges as the glossiness is decreased. With the regular Fresnel, objects with low glossiness may appear to be unnaturally bright and "glowing" at the edges. The glossy Fresnel calculations make this effect more natural.

 

Environment override


 



Use environment override – When enabled, additional parameters are available to adjust the environment settings for this material.

Environment Override – A color or texture that is used as an environment for the material.

Environment Priority – A reflected or refracted ray can go through several materials in a scene. To tell V-Ray to use this material's environment, set this parameter to a lower value than other materials in the scene.  

 

Reflection/Refraction Interpolation

These parameters determine the options for the interpolation of glossy reflections and refractions. They are very similar to the options for the irradiance map. Note that it is not recommended to use interpolation for animated sequences since this might cause severe flickering.

 

 

 

V-Ray Mtl Common


The V-Ray Mtl Common tab includes rollouts like Layer and Bump and Displacement, which includes settings that are general among many V-Ray (and Modo) Materials. For more details, please see the Common V-Ray Material Attributes page.

 

Maps can also be assigned to create a material that has a non-uniform opacity in the Shader tree with a vmtl Opacity effect for the map. When a map is used, white is completely opaque and black is completely transparent. For more details, please see the Opacity example.