This page provides information about the Emissive material in V-Ray for SketchUp.
Overview
The Generic V-Ray material's Emissive preset is generally used for producing self-illuminated surfaces.
UI Paths
||V-Ray Asset Editor|| > Materials (right-click) > Emissive
||V-Ray Asset Editor|| > Create Asset (left-click) > Materials > Emissive
UI Options
The Emissive material settings are organized in Basic and Advanced modes. Switch the mode from the toggle button under the Preview Swatch or globally from the Configuration rollout of the Settings tab.
The Add Layer and Add Attribute buttons are provided for some V-Ray materials, including Emissive. For more information, see the Attributes section and the Layers section on Materials page.
The Emissive material itself is created by adding an Emissive layer.
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.
Emissive
Some options are available only in Advanced mode.
Color – Specifies the color of the light. A texture can be specified as well. See the Color and Texture examples below for more information.
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. 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).
Multipliers
This rollout is available only in Advanced 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).
Intensity – Controls the strength of the light.
Transparency – Controls the intensity of the Transparency Color, which determines the color that is transparent.
Example: Color and Texture, Intensity, Emit On Back Side
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.
Transparency Texture On/Off
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.
Intensity: 10
Color: Blue
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 vice versa.
Opacity – Enables refraction/opacity binding. Changing the SketchUp material opacity, however, does not change the V-Ray material. Instead, it disables the Opacity binding.
Texture Mode – Enables texture binding. Changing the V-Ray material texture changes the corresponding base application material texture and vice versa.
Auto – By default binds the Diffuse texture to the base app material.
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.
Custom – Allows the use of a custom texture as base application material map. Disabling this parameter allows changing the base app material texture without affecting the V-Ray material.
Bake – In this mode complex texture networks are baked to a single image used as a viewport preview. Differences between the rendered result and the viewport preview may occur due to the fact that only the texture confined within the 0 to 1 UV square is baked. This affects most procedural patterns and textures with custom UV placement configuration. Raytraced and Tri-planar textures are not supported.
It is recommended to save all raw bitmap buffers (textures embedded in SketchUp like SketchUp library materials textures) to disk before activating the Bake mode to preserve them.
If a Emissive material contains multiple layers, only the top-most one is regarded in Auto binding mode.
Texture – Selected textures are displayed in the viewport. Keep in mind that procedural textures are not displayed. Note that the viewport texture will not affect the way the material is rendered in V-Ray. It is mainly used for preview purposes.
Override Control
Can be Overridden – When enabled, the material can be overridden by the Material Override option in the Settings.
Attributes
The attributes from the following expandable menus are available for the Emissive material.
Notes
- You can use the Emissive material as a light source assigned to an object. Increasing 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 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 Emissive 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 Blend material. This restriction will probably be removed in a future release.
- The 2D mapping (landscape) method only supports one UV mapping channel.
- – Calculated in the default SketchUp unit - inches.