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This page provides information about the Emissive material in V-Ray for Revit.

 

Overview

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The Generic V-Ray material's Emissive preset Emissive is generally used for producing self-illuminated surfaces.

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UI Options

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The Emissive material settings are organized in Basic and Advanced modes. Switch the mode from the toggle button under the Preview Swatch.

Add Layer and Add Layer buttons are provided for some V-Ray materials, including Emissive. You can select an additional layer that can add up to the appearance of the material. For more information, see the Attributes And Layers section.

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Holding down Ctrl while having the Add Attribute or Add Layer menu open, allows selecting multiple entries without closing the dropdown.

The context menu of the Color slot provides options to Copy and Paste, as well as to Reset the color.

A Reset option is provided in the context menu of each Number Slider. You can reset the slider value to the default one.

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Emissive

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Some options are available only in Advanced mode.

Color – – Specifies the color of the light. A texture can be specified as well. For See the Color and Texture examples below for more information, see the Textures example below.

Intensity – Controls the strength of the light.

Transparency – Specifies the color that is transparent. For this parameter black stands for opaque and white for transparent color. A texture can be specified as well. See the Transparency Texture example below for more information.

Emit On Back Side – When enabled, the object emits light from its back side as well. When disabled, only the front side emits light, and the material renders as black on the back sides. For more information, see the Higher Multiplier/2-Sided On and Off example below. See the Emit On Back Side examples below for more information.

Compensate EV – Used when rendering with the V-Ray Physical Camera. When enabled, the intensity of the material is adjusted to compensate for the camera exposure.

Color *Opacity – When enabled, the color of the light material is multiplied by the opacity texture. Otherwise, the color and opacity act independently (so-called additive transparency).

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Multipliers

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This rollout is available only in Advanced mode.

Mode Mode – Specifies one of the following methods for adjusting textures.

Multiply – – Multipliers can be specified to adjust colors and textures.
Blend Amount – Blend amounts can be specified to adjust colors and textures.

Color – Controls the intensity of the Emissive Color (light color). See the Default Color and Multiplier Values example. 

Intensity – Controls the strength of the light.

Transparency – Controls the intensity of the Transparency Color, which determines the color that is transparent.

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  Anchortexturestextures

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Example: Color and Texture, Intensity, Emit On Back Side
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Examples
Examples

Here are some examples showing the difference in Intensity, the Emit On Back Side turned on and off and using an image in the Color Texture slot

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Example: Textures

This example shows using the BRDFLight 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 parameter in the Color Balance roll out of the texture.

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Intensity: 1


Color Multiplier:  3.0
GI on ;
Emit on Back Side on
Using a File texture connected to the Color slot. The Color Multiplier is quite low, so only the plane and the reflection on the teapot are visible.White
Emit On Back Side: Off

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Intensity: 5
Color Multiplier: 15.0
GI on ; : White
Emit on On Back Side  on
Increasing the Color Multiplier leads to a much lighter overlook of the scene. Notice that now the texture is getting closer to white color look, due to multiplying the (R,G,B) values of the texture.: Off

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Intensity: 1


Color Multiplier: 3.0
GI on ; : White
Emit on Back Side on
  Here is another File texture connected to the Color slot. Notice that we haven't changed the VRayMtls for the surrounding walls, but the scene looks different from the previous one due to the new texture.On Back Side: On

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Intensity: 5


Color Multiplier:  15.0
GI on ;
Emit on Back Side on
Increasing the Color Multiplier leads to a much lighter overlook of the scene. Notice now that the texture is getting closer to white color look, due to multiplying the (R,G,B) values of the texture.White
Emit On Back Side: On

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Intensity: 5
Image loaded in the Color Texture slot.
Emit On Back Side: on

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  AnchordefaultColorAndMultiplierdefaultColorAndMultiplier

 

Example: Default Color and Multiplier Values

Here is a scene rendered with the default BRDFLight. These examples demonstrate how the material behaves in V-Ray, and how its parameters influence the overlook of the final results.

 

Transparency Texture On/Off
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Transparency Texture
Transparency Texture

This example shows the usage of an image in the Transparency Texture slot. Both renders have the Emit On Back Side function turned on as well.

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The white plane is a default BRDFLight. The teapot is a default VRayMtl with Reflection. Rest is just VRayMtl with diffuse colors.

We are going to render this scene with Default Lights - Off till the end of the example and no lights will be used in it as well.

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Color value: 1.0
No GI

As you see the image is absolutely dark except the plane (self-illuminated) and the reflection on the teapot. Notice we have no GI and no lights at all here, so the dark part of the scene is totally expected and reasonable.

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Color value: 50.0
No GI

Notice that nothing changed in general, BUT the reflection on the teapot got stronger due to the higher color value. Rest is still black: because we still have the GI off.

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Color value: 1.0
GI on

As You see turning GI on almost didn't change the overlook. That is because of the Color value: 1.0. It acts mainly as just self-illuminating the object that has the BRDFLight.

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Intensity: 10
Color: Blue

 

Override Control

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Can be Overridden – When enabled, the material can be overridden when you enable the Opaque override option in the Global Overrides tab of Appearance Manager.
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Attributes

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The attributes from the following expandable menus are available for the Emissive material.

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Attributes

 

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titleTranslucency

Translucency

Multiexcerpt include
MultiExcerptNameTranslucency Attribute
PageWithExcerptTranslucency Attribute

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titleBump

Bump

Multiexcerpt include
MultiExcerptNameBump Attribute
PageWithExcerptBump Attribute

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titleContour

Outline

Multiexcerpt include
MultiExcerptNameOutline Attribute
PageWithExcerptOutline Attribute

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titleDisplacement

Displacement

Multiexcerpt include
MultiExcerptNameDisplacement Attribute
PageWithExcerptDisplacement Attribute

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titleRaytrace Properties

Raytrace Properties

Multiexcerpt include
MultiExcerptNameRaytrace Properties Attribute
PageWithExcerptRaytrace Properties Attribute

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titleOverride

Override

Multiexcerpt include
MultiExcerptNameOverride Attribute
PageWithExcerptOverride Attribute

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titleMaterial ID

Material ID

Multiexcerpt include
MultiExcerptNameMaterial ID Attribute
PageWithExcerptMaterial ID Attribute

 

Layers

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The Layers available for the Emmisive material are as follows.

VRay Mtl

Emissive

Diffuse Coat

Reflective Coat

Flakes 2

Stochastic Flakes

 

 

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Example: Higher Multipliers/2-Sided On and Off

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Color value: 5.0
GI on
Emit on Back Side off

Now you can notice that increasing the Color value has influenced visibly the scene (shadows also appear).

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Color value: 5.0
GI on
Emit on Back Side on

Scene starting to gather more light because of the 2-sided - on.

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Color value: 15.0
GI on
Emit on Back Side off

As you see the back is still dark, but You can already notice the blue wall receiving some GI, due to higher Color value. Shadows also appear more defined.

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Color value: 15.0
GI on
Emit on Back Side on

Scene starting to gather more light because of the 2-sided - on.

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For all other material settings, see the Attributes section on Materials page.

Notes

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  • You can use the
    • BRDFLight
  • Emissive material as a light source assigned to an object. Increasing
    • the Value of
  • the Value of the color affects the GI solution and produces more light. Note that overbright colors may look the same as pure white but the GI results is 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 if
  • for the Emissive 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
  • Emissive material is the only material applied on the object. They will not work if the material is part of a complex material like a
    • VRayBlendMtl
  • Blend material. This restriction will probably be removed in a future release.