Page Contents

 

Overview


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

 

 

 

 

Diffuse





Diffuse – The diffuse color of the material. Note the actual diffuse color of the surface also depends on the reflection and refraction colors. See the Energy preservation parameter below.

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

 

 


Example: The Roughness Parameter

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

 

 

Roughness = 0.0  
(regular diffuse material)

Roughness = 0.3

Roughness = 0.6

 

 

Reflection






Reflection – Enables reflection of the material. 

Reflection Color – Specifies the reflection color. Note that the reflection color dims the diffuse surface color based on the Energy preservation option. For more information, please see the Reflection Color Parameter example below.

Highlight Glossiness – Enables a separate glossiness control for the specular highlights of the material. Enabling this option and setting the value to 1.0 disables the specular highlights. 

Reflection Glossiness – Specifies the sharpness of reflections. A value of 1.0 means perfect mirror-like reflection; lower values produce blurry or glossy reflections. Use the Subdivs parameter below to control the quality of glossy reflections. For more information, please see the Reflection Glossiness Parameter example below.

Fresnel – When enabled, the reflection strength depends on the viewing angle of the surface. Some materials in nature (e.g. glass, etc.) reflect light in this manner. Note that the Fresnel effect depends on the index of refraction as well. For more information, please see the Fresnel Option example below.

Reflection IOR  – When disabled, the Refraction IOR is used as Reflection IOR. Enable for finer control over the Reflection IOR. 

BRDF – Determines the type of BRDF (the shape of the highlight). The use of GGX model is recommended for metals and other highly reflective materials. For more information, please see the BRDF Type example below.

Phong
Blinn
Ward
Microfacet GTR (GGX)

Back Side Reflect – When disabled, reflections are calculated for the front side of the objects only. When enabled back-side reflections will also be calculated. 

Max depth – Specifies the number of times a ray can be reflected. Scenes with lots of reflective and refractive surfaces may require higher values to look right.

Affect Channels – Specify which channels will be affected by the reflectivity of the material.

Color Only – The reflectivity of the material 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 – The reflectivity of the material will affect all channels and render elements.

GTR Tail Falloff – Active only when the BRDF is set to GGX. It allows fine tuning of the specular reflections by controlling the rate at which the sharp specular highlight fades out. Higher values create a value spread out the fade out of the highlight. This parameter does not affect the size of the actual highlight - this is controlled by the Reflect glossiness paramater. For more information, please see the GTR tail falloff example below.


Anisotropy



 

Anisotropy (-1 to 1) – Determines the shape of the highlight. A value of 0.0 means isotropic highlights. Negative and positive values simulate brushed surfaces. For more information, please see the Anisotropy example below.

Rotation – Determines the orientations of the anisotropic effect in a float value between 0 and 1 (where 0 is 0 degrees and 1 is 360 degrees). For more information, see the Rotation example below.

Derivation – Determines the anisotropy orientation method. 

Local Axis – The orientation of the anisotropic reflection/highlight is based on the object's local X, Y or Z axis. 
UVW – When enabled, the orientation of the anisotropic reflection/highlight is based on the specified map channel/set. 

Local Axis – Specifies a local axis used for Anisotropy orientation. (X, Y, Z)

 Map Channel/Set – Specifies a map channel that is used for the anisotropic reflections/highlights orientation. 


Dim Distance




Dim Distance – Enables Dim Distance. 

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

Dim Falloff –  Sets a fall off radius for the dim distance. 



Example: The Reflection Color Parameter

This example demonstrates how the Reflection 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 = Medium Gray.
(128, 128, 128)

Reflection color = White.
(255, 255, 255)

 

 

 


Example: The Reflection Glossiness Parameter

This example demonstrates how the Reflection glossiness  and Highlight glossiness parameters control the highlights and reflection blurriness of the material.

 

 

Reflection/Highlight Glossiness = 1.0
(perfect mirror reflections)

Reflection/Highlight Glossiness = 0.8

Reflection/Highlight Glossiness = 0.6

 

 

 


Example: The Fresnel Option

This example demonstrates the effect of the Fresnel option. Note how the strength of the reflection varies with the IOR of the material. For this example, the Reflection color is pure white (255, 255, 255).

 

Fresnel = On
IOR  =  1.3

Fresnel = On
IOR = 2.0

Fresnel = On
IOR = 10.0

Fresnel = Off.

 

Refraction


 

 

Refraction – Enables Refraction of the material. 

Refraction Color – Specifies the refraction color. Note that the actual refraction color depends on the reflection color as well. See the Energy preservation parameter below. For more information about refraction color, please see the Refraction Color Parameter example below.

Fog color – Specifies the attenuation of light as it passes through the material. This option allows to simulate 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 unless the Fog system units scaling is enabled. The fog color also determines the look of the object when using translucency. For more information, please see the Fog Color Parameter and Fog Multiplier Parameter examples below.

Fog Multiplier Smaller values reduce the effect of the fog, making the material more transparent. Larger values increase the fog effect, making the material more opaque.

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).

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. For more information, please see the Refraction IOR Parameter example below.

Refraction Glossiness – Specifies the sharpness of refractions. A value of 1.0 produces perfect glass-like refraction; lower values produce blurry or glossy refractions. Use the Subdivs parameter below to control the quality of glossy refractions. For more information, please see the Refraction Glossiness Parameter example below.

Affect shadows – When enabled, the material will cast transparent shadows, depending on the refraction color and the fog color. This only works with V-Ray shadows and lights.

Max depth – Specifies the number of times a ray can be refracted. Scenes with lots of refractive and reflective surfaces may require higher values to look right.

Affect channels – Specifies which channels will be affected by the transparency of the material.

Color Only – The transparency of the material 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. Note that currently this works only with clear (non-glossy) refractions.
All channels
– The transparency of the material will affect all channels and render elements.

 

Dispersion


 

 

Dispersion – When enabled, true light wavelength dispersion will be calculated. For more information, please see the Dispersion example below.

Abbe – Increases or decreases the dispersion effect. Lowering it widens the dispersion and vice versa.

 

Translucency


 

 

Translucency – Enables Refraction 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. 

Hard (wax) model  – This model is specifically suitable for hard materials like marble. 
Color+alpha
 
– This is the most realistic SSS model and is suitable for simulating skin, milk, fruit juice and other translucent materials. 

Back-side Color – This parameter allows you to additionally tint the SSS effect. 

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

Fwd/back Coeff – Controls the direction of scattering for a ray. 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).

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

Light Multiplier – Multiplies the translucent effect. 

 

 


Example: The Refraction Color Parameter

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 Diffuse color, white Reflection color, and the Fresnel option is turned on.

 

 

Refraction color = Black
(0, 0, 0)
no refraction

Refraction color = Light Gray
(192, 192, 192)

Refraction color = White
(255, 255, 255)

 

 

 


Example: The Fog Color Parameter

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: The Fog Multiplier Parameter

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 = 0.5

Fog multiplier = 1.0

Fog multiplier = 1.5

 

 


Example: The Refraction IOR Parameter

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: The Refraction Glossiness Parameter

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: The Refraction Depth Parameter

This example demonstrates the effect of the Refraction 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 depth .

 

Refraction depth = 1
Reflection depth = 5

Refraction depth = 2
Reflection depth = 5

Refraction depth = 4
Reflection depth = 5

Refraction depth = 8
Reflection depth = 5

Refraction depth = 8
Reflection depth = 8

 

 


Example: Dispersion

This example demonstrates the Dispersion capabilities of the V-Ray material and the effect of the Abbe parameter.

 

 

Dispersion = Off

Dispersion = On
Abbe = 10

Dispersion = On
Abbe = 50

 

 


Example: BRDF Type

This example demonstrates the differences between the BRDFs available in V-Ray. Note the different highlights produced by the different BRDFs.

 

 


BRDF type = Phong

 


BRDF type = Blinn

 


BRDF type = Ward

 


BRDF type = GGX

 

 

 

 


Example: GTR Tail Falloff

This example demonstrates the effect of the GTR tail falloff parameter.

 

 


GTR tail falloff: 0.01

 


GTR tail falloff: 1.0

 


GTR tail falloff: 2.0
(default value)

 

 

 

 


Example: The Anisotropy Parameter

This example demonstrates the effect of the Anisotropy parameter. Note how the different values stretch the reflections horizontally or vertically.

 

Anisotropy = -0.9

Anisotropy = -0.45

Anisotropy = 0.0
no anisotropy

Anisotropy = 0.45

Anisotropy = 0.9


 

 


Example: The Rotation Parameter

This example demonstrates the effect of the Rotation parameter. For all the images in this example, the Anisotropy parameter itself is 0.8.

 

Anisotropy rotation =
0.0 degrees

Anisotropy rotation =
45.0  degrees

Anisotropy rotation =
90.0  degrees

Anisotropy rotation =
135.0  degrees

Anisotropy rotation =
Bitmapped 
map in the upper-right corner

 

Opacity


 

 

Opacity – Specifies how opaque or transparent the material is. A texture map can be assigned to this channel. 

Mode – Controls how the opacity map works. 

Normal – The opacity map is evaluated as normal. The surface lighting is computed and the rays is continued for the transparent effect. 
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 on the opacity texture. This is the fastest mode, but it might increase flickering when rendering animation. 
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 grayscale values. The opacity texture is still filtered as normal. 

Custom Source – When enabled, V-Ray uses an alpha channel to control the material opacity. 

Diffuse Texture Alpha – The diffuse texture alpha channel controls the opacity. Diffuse Texture Alpha source works the same way as Diffuse Map Alpha as Transparency legacy option from the V-Ray versions before 3.60. 
Opacity Texture Alpha – The opacity texture alpha channel controls the opacity, instead of the default texture intensity. If there is no texture in the source slot, the option will be ignored. 


Advanced Options



 

 

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

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.

Use irradiance map – When enabled, the irradiance map will be used to approximate diffuse indirect illumination for the material. When disabled, brute force GI will be used. This can be used for objects in the scene which have small details and are not approximated very well by the irradiance map.

Fog Units Scaling – When enabled, the fog color attenuation becomes dependent on the current system units.

Linear workflow – When enabled, V-Ray will adjust sampling and exposure to use the Gamma 1.0 curve. This is disabled by default.

Cutoff Threshold – 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.

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 be less that or equal to the light falling on the surface (as this happens 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.

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

 

Multipliers


 

 

Mode – Specifies if Multiplier or Blend Amount parameters will be used to control the intensity of other parameters.

Multiplier – For applicable parameters, intensity will be controlled through a Multiplier parameter.
Blend Amount – For applicable parameters, intensity will be controlled through a Blend Amount parameter.

Diffuse – Controls the intensity of the Diffuse color.

Reflection Color – Controls the intensity of the reflection color.

Reflection Glossiness – Controls the intensity of the reflection sharpness.

Refraction Color – Controls the intensity of the refraction color.

IOR – Controls the intensity of the Index of Refraction value when calculating refraction.

Refraction Glossiness – Controls the intensity of the refraction sharpness.

Opacity – Controls the intensity of the overall material Opacity.

 

Material Options


 

 


Can be Overridden – When enabled, the material will be overridden when you enable the override color option in the Global Switches.

Alpha contribution – Determines the appearance of the object in the alpha channel of the rendered image.

Normal (1) – A value of 1.0 means the alpha channel will be derived from the transparency of the material.
Ignore in Alpha (0)   A value of 0.0 means the object will not appear in the alpha channel at all. 
Black Alpha (-1) – A value of -1.0 means that the transparency of the material will cut out from the alpha of the objects behind. 

ID Color – Allows you to specify a color to represent this material in the Material ID VFB render element. 

Cast Shadows – When disabled, all objects with this material applied will not cast shadows.

Only in Secondary – When enabled, objects with this material applied will only appear in reflections and refractions and will not be directly visible to the camera.



Maps


These determine the various texture maps used by the material.

Bump/Normal Mapping

 

 

 

Bump/ Normal Mapping – Enables or disables the bump or normal effect.

Mode/Map – Specifies the map type. 

Bump Map
Local Space Bump 
Normal map 

Amount – Multiplier for the bump/normal map. 

Advanced Options

 

Normal Map Type – Specifies the normal map type. 

Tangent space
Object space
Screen space
World space 

Delta Scale – Decrease the value of the parameter to sharpen the bump, increase it for more blurry effect of the bump. 

 

Displacement




Displacement – Enables or disables the displacement effect.

Mode/ Map – Specifies the mode in which the displacement is rendered. 

2D Displacement – Bases the displacement on a texture map that is known in advanced. The displaced surface is rendered as a warped height-field based on that texture map. The actual raytracing of the displaced surface is done in texture space and the result is mapped back into 3D space. The advantage of this method is that it preserves all details in the displacement map. However, it requires the object to have valid texture coordinates. You cannot use this method for 3d procedural textures or other textures that use object or world coordinates. The parameter can take any values. 
Normal Displacement – Takes the original surface geometry and subdivides its triangles into smaller sub-triangles, which then are displaced. 

Amount – The amount of displacement. A value of 0.0 means the object appears unchanged. Higher values produce a greater displacement effect. This parameter can also take a negative value, in which case the displacement pushes geometry inside the object. 

Shift – Specifies a constant, which is added to the displacement map values, effectively shifting the displaced surface up and down along the normals. This can be either positive or negative.

Keep continuity – When enabled, tries to produce a connected surface, without splits, when there are faces from different smoothing groups and/or material IDs. Note that using material IDs is not a very good way to combine displacement maps since V-Ray cannot always guarantee the surface continuity. Use other methods (vertex colors, masks etc.) to blend different displacement maps.

View dependent – When enabled, Edge length determines the maximum length of a subtriangle edge in pixels. A value of 1.0 means that the longest edge of each subtriangle is about one pixel long when projected on the screen. When disabled, Edge length is the maximum sub-triangle edge length in world units.

Edge length – Determines the quality of the displacement. Each triangle of the original mesh is subdivided into a number of subtriangles. More subtriangles mean more detail in the displacement, slower rendering times and more RAM usage. Less subtriangles mean less detail, faster rendering and less RAM. The meaning of Edge length depends on the View dependent parameter. 

Max subdivs – Controls the maximum sub-triangles generated from any triangle of the original mesh when the displacement type is Subdivision. The value is in fact the square root of the maximum number of subtriangles. For example, a value of 256 means that at most 256 x 256 = 65536 subtriangles will be generated for any given original triangle. It is not a good idea to keep this value very high. If you need to use higher values, it will be better to tessellate the original mesh itself into smaller triangles instead. The actual subdivisions for a triangle are rounded up to the nearest power of two (this makes it easier to avoid gaps because of different tessellation on neighboring triangles). 

Water Level – Clips the surface geometry in places where the displacement map value is below the specified threshold. This can be used for clip mapping a displacement map value below which geometry will be clipped. 

Level Height – Value below which the geometry is clipped. 

 

Environment Overrides


Allows Background, Reflection, and Refraction maps from Environment Settings to be overridden for the current material.

 

 

 

Background Environment

Texture – Specifies a texture to be used as the overriding map.

Multiplier – Specifies a multiplier for the overriding map.

Reflection Environment

Texture – Specifies a texture to be used as the overriding map.

Multiplier – Specifies a multiplier for the overriding map.

Refraction Environment

Texture – Specifies a texture to be used as the overriding map.

Multiplier – Specifies a multiplier for the overriding map.

 

Binding


 

 

Binding – Enables connection/binding between V-Ray and the corresponding base application material. 

Color – Enables color binding. Changing the V-Ray material color changes the corresponding base application material color and vise versa. 

Texture – Enables texture binding. Changing the V-Ray material texture changes the corresponding base application material texture and vise versa. 

Auto – By default binds the Diffuse texture to the base app material. Clicking on the "eye" icon for a texture used in the shader hierarchy, changes the binded map to the newly selected one. 
Texture Helper – Allows the use of a helper texture as a base application material map. The same helper is used if the binded texture is a procedural map. This is useful if every time you have to set texture placement for a map that can't be displayed accurately in the base app. 

Disabling this parameter allows changing the base app material texture without affecting the V-Ray material. 

Opacity – Enables opacity/ transparency binding. Changing the V-Ray material refraction changes the corresponding base application material opacity/ transparency and vise versa. 

 

 

Notes


  • Use the VRayMtl/VRayBRDF whenever possible in your scenes. This material is specifically optimized for V-Ray and often GI and lighting is computed much faster for V-Ray materials than for standard materials. Many V-Ray features (e.g. light cacherender elements ) are guaranteed to work properly only with VRayMtl and other V-Ray compliant materials.
  • VRayMtl can produce reflections/refractions for matte objects - see Wrapper Material | MtlWrapper.