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The Reflection tab is part of the V-Ray Material parameters.

Reflection

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Column width 57% BRDF Type – Determines the type of BRDF (the shape of the highlight). See the BRDF type example for more information. GGX – GGX Microfacet highlight/reflections. Specular highlights have a bright center with a longer falloff. Phong – Phong highlight/reflections. Specular highlights have a bright center with no falloff. Blinn – Blinn highlight/reflections. Specular highlights have a bright center with a tight falloff. Ward – Ward highlight/reflections. Specular highlights have a bright center with a falloff broader than Blinn, but tighter than Microfacet GTR (GGX). UI Text Box type tip 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. Expand title 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 a broader highlight center with a tight falloff. The Ward model has an even broaded 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. Color – Specifies the reflection color of the material. Note that the reflection color dims the diffuse surface color. See the Reflection Color example for more information. Texture – Specifies a texture file to be used for the reflection. Mix Strength – Specifies a blend amount between the texture map and the color. Glossiness –  Controls the sharpness of reflections. A value of 1.0 creates perfect mirror-like reflections; lower values produce blurry or glossy reflections. Use the Reflection Subdivs parameter to control the quality of glossy reflections. See the Reflection Glossiness example for more information. Texture – Specifies a texture file to be used for the glossiness. Mix Strength – Specifies a blend amount between the texture map and the glossiness amount. GGX Tail Falloff – Controls the transition from highlighted areas to non-highlighted areas when the BRDF Type is set to GGX. Texture – Specifies a texture file to be used for the GGX Tail Falloff. Mix Strength – Specifies a blend amount for the texture map. Mix Type – Specifies how the texture file is blended with the GGX Tail Falloff value. The texture is applied to a layer above the Falloff value. Normal – When applied, the texture is blended normally. A Mix Strength of 100% makes the texture completely opaque, hiding the Falloff value below. Add – When applied, the texture's value is added to the Falloff value. Subtract – When applied, the Falloff value is subtracted from the texture's value. Multiply – When applied, the texture is multiplied by the Falloff value. Metalness – Controls the reflection model of the material from dielectric (metalness 0.0) to metallic (metalness 1.0). Note that intermediate values between 0.0 and 1.0 do not correspond to any physical material. This parameter can be used with PBR setups coming from other applications. The reflection color should typically be set to white for real world metals. Texture – Specifies a texture file to be used for the metalness. Mix Strength – Specifies a blend amount between the texture map and the metalness amount. GTR Energy Compensation – Compensates GTR lost energy and an accurate Fresnel formula for conductors is used for metals. This option is enabled by default for all newly created materials and is hidden from the UI. It is visible in older scenes. Use Roughness –  This option controls how Glossiness is interpreted. When Use Roughness is selected, the Glossiness inverse value is used. For example, if Glossiness  is set to 1.0 and Use Roughness is selected, this results in diffuse shading. Conversely, if Glossiness is set to 0.0 and Use Roughness is selected, this results in sharp reflection highlights.  Use Bump to Glossiness – This option is available only when a Bump texture is attached to the material. Enable this to convert the Bump texture into a Glossiness texture and use it as a Glossiness input. This method creates more matte highlights.   Column width 5% Column width 38% Image Removed

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BRDF BRDF

Example: BRDF Type

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The following examples demonstrate the different Types of BRDF.

Fresnel

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Column width 57% Fresnel Reflections — When enabled, makes the reflection strength dependent on the viewing angle of the surface. Some materials in nature (glass etc) reflect light in this manner. Note that the Fresnel effect depends on the index of refraction as well. See the Fresnel example for more information. Lock Fresnel IOR – Allows the user to unlock the Fresnel IOR parameter for finer control over the reflections. Fresnel IOR –  The Index of reflection to use when calculating Fresnel reflections. Normally this is locked to the Refraction IOR parameter, but you can unlock it for finer control. A texture can be attached to this slot. Texture – Specifies a texture file to be used for the Fresnel IOR. Mix Strength – Specifies a blend amount between the texture map and the fresnel IOR value. Mix Type – Specifies how the texture file is blended with the Fresnel IOR value. The texture is applied to a layer above the Fresnel IOR value. Normal – When applied, the texture is blended normally. A Mix Strength of 100% makes the texture completely opaque, hiding the Fresnel IOR value below. Add – When applied, the texture's value is added to the Fresnel IOR value. Subtract – When applied, the Fresnel IOR value is subtracted from the texture's value. Multiply – When applied, the texture is multiplied by the Fresnel IOR value.   Column width 5% Column width 38%

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reflectionColor reflectionColor

 

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Column width 10%   Column width 30% 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).   Column width 20% Column width 30% Example: Fresnel 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 pure white (255, 255, 255).   Column width 10%

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Column width 50% Image slider minLabel Black (0, 0, 0) maxLabel White (255, 255, 255) Panel borderStyle none Reflect = 0, 0, 0 Panel borderStyle none Reflect = 51, 51, 51 Panel borderStyle none Reflect = 102, 102, 102 Panel borderStyle none Reflect = 153, 153, 153 Panel borderStyle none Reflect = 204, 204, 204 Panel borderStyle none Reflect = 255, 255, 255     Column width 50% Image slider minLabel 1.6 maxLabel 7.6 Panel borderStyle none Fresnel IOR = 1.6 Panel borderStyle none Fresnel IOR = 2.2 Panel borderStyle none Fresnel IOR = 2.8 Panel borderStyle none Fresnel IOR = 3.4 Panel borderStyle none Fresnel IOR = 4.0 Panel borderStyle none Fresnel IOR = 4.6 Panel borderStyle none Fresnel IOR = 5.2 Panel borderStyle none Fresnel IOR = 5.8 Panel borderStyle none Fresnel IOR = 6.4 Panel borderStyle none Fresnel IOR = 7.0 Panel borderStyle none Fresnel IOR = 7.6

 

 

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reflectionGlossiness reflectionGlossiness

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Column width 10%   Column width 30% Example: Reflection Glossiness This example demonstrates how the Glossiness parameter controls the highlights and reflection blurriness of the material. Fresnel IOR = 3.5. Column width 20%   Column width 30% Example: Max Depth   This example demonstrates the effect of the reflection Max depth parameter.   Column width 10%

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Column width 50% Image slider minLabel 0.0 startIndex 11 maxLabel 1.0 Panel borderStyle none Glossiness = 0.0 Panel borderStyle none Glossiness = 0.1 Panel borderStyle none Glossiness = 0.2 Panel borderStyle none Glossiness = 0.3 Panel borderStyle none Glossiness = 0.4 Panel borderStyle none Glossiness = 0.5 Panel borderStyle none Glossiness = 0.6 Panel borderStyle none Glossiness = 0.7 Panel borderStyle none Glossiness = 0.8 Panel borderStyle none Glossiness = 0.9 Panel borderStyle none Glossiness = 1.0     Column width 50% Image slider minLabel 1 startIndex 2 maxLabel 10 Panel borderStyle none Reflection Max Depth = 1 Panel borderStyle none Reflection Max Depth = 3 Panel borderStyle none Reflection Max Depth = 5 Panel borderStyle none Reflection Max Depth = 8 Panel borderStyle none Reflection Max Depth = 10

Anisotropy

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Column width 57% Anisotropy (-1..1) –  Determines the shape of the highlight. A value of 0.0 means isotropic highlights. Negative and positive values simulate "brushed" surfaces. See the Anisotropy example for more information. A texture can be attached to this slot. Anisotropy Rotation – Determines the orientation of the anisotropic effect in a float value between 0.0 and 1.0 (where 0.0 is 0 degrees and 1.0 is 360 degrees). See the Anisotropy example for more information. A texture can be attached to this slot. UV Vectors Derivation – Specifies the method for deriving anisotropy axes: Local object Axis – Uses a local axis for the anisotropy effect.  UV Space –  Anisotropy Axis – Specifies a local object axis for the anisotropy effect when UV Vectors Derivation is set to Local object axis.   Column width 5% Column width 38%

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Example: The Anisotropy and Rotation Parameters

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Thin Film

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Example: Thickness Min (nm)

This example shows how the Thickness Min (nm) parameter affects the V-Ray material, when no Thickness Blend is applied. The Thin Film IOR is set to 1.4.

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Reflection Advanced

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