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This page provides information on the BRDFLight material node.

 

Page Contents

Table of Contents
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Overview

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The BRDFLight material is a special material provided with the V-Ray renderer. This material is generally used for producing self-illuminated surfaces. This material's light emission can be used as indirect as well as direct illumination in the scene.

This allows for light sources of any shape, and may even be assigned at the object level and at the face level for self-illuminating only portions of a mesh.

 

 

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UI Paths

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||shop Network|| > Material > V-Ray Material node > V-Ray > Material > Light

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 ||mat Network|| > V-Ray > Material > Light

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Node

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The BRDFLight node provides inputs for controlling various material properties. Most correspond to parameters in the section below.

 

 

 

Parameters

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Light Color – Controls the color of the light material.

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defaultColorAndMultiplier
defaultColorAndMultiplier

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Example: Default Color and Multiplier Values


For the examples below, the interior cube is the default BRDFLight material. The exterior cube and ground plane have the default VRayMtl with Reflection. The rest of the scene is shaded with a basic diffuse VRayMtl.

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Color Multiplier: 50.0
Compensate Camera Exposure: off
GI: off

The inner cube and reflections are noticeably brighter. With GI disabled, the image remains in darkness.

 

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Color Multiplier: 50.0
Compensate Camera Exposure: on
GI: off

By enabling Compensate Camera Exposure, the reflections become brighter with the current Color Multiplier value.

 

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Color Multiplier: 50.0
Compensate Camera Exposure: off
GI: on

With GI enabled, the scene receives more illumination with the current Color Multiplier value.

 

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textures

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Example: Textures


This example shows using the BRDFLight material with a texture in the Color slot. In order to control the strength of the light we will need to adjust the value of the Color Multiplier.

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EmitOnBack
EmitOnBack

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Example: Emit On Back Side


In the examples below, the BRDFLight material is applied to the curved plane.

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Color Multiplier: 1.0
GI: on
Emit on Back Side: off

Increasing the multiplier visibly influences the scene. Shadows appear.

 

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Color Multiplier: 1.0
GI: on
Emit on Back Side: on

The scene starts to gather more light with Emit on Back Side enabled.

 

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Color Multiplier: 15.0
GI: on
Emit on Back Side: off

The back is still dark, but notice the blue wall receives some GI due to higher Color Multiplier value. Shadows appear more defined.

 

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Color Multiplier: 15.0
GI: on
Emit on Back Side: on

The scene gathers more light with Emit on Back Side enabled. Be aware of resulting burnt areas when using the Linear type of Color mapping.

 

 

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Notes
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Notes

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  • You can use the BRDFLight material as a light source assigned to an object. Increasing the Value of the color will affect the GI solution and will produce more light. Note that overbright colors may look the same as pure white but the GI results will be different.
  • If you know the photometric power of a self-illuminated object in lumens (e.g. 1700 lm for a 100-watt bulb) you can calculate the multiplier for BRDFLight material if you divide the lumens by the surface area of the object in meters, provided that the self-illuminated color is pure white.
  • The direct illumination options currently only work properly if the BRDFLight material material is the only material applied on the object. They will not work if the material is part of a complex material like a BRDFLayeredMtl material. This restriction will probably be removed in a future release.