The Texture Emission node is used to make a mesh behave as a light source. It is used with a Diffuse material type connected to the Emission parameter. This allows any valid texture type to set the light intensity. Using an image texture is a great way to create the effect of a screen or monitor that casts light into a scene as shown in Figure 1.
Figure 1: Texture emission nodes are a great way to create glowing screen effects.
Figure 2 shows the location of the Octane Texture emission under the Octane Emission section in the Create Render Node window of Maya’s Hypershade. Figure 3 shows the parameters of the Texture Emission nodes.
Figure 2: Octane Texture Emission node is found in the Emission section of the Octane nodes in the Hypershade.
Texture Emission Parameters
Figure 3: The parameters of the Octane Texture Emission node.
Texture Emission Parameters
Efficiency or Texture
Is used to determine how far the light is cast into the scene based on its power settings. No light is 100% efficient at delivering the power at the specified wattage (a 100 watt light bulb does not actually deliver 100 watts of light.) The efficiency setting can be used to enter the real world values. These values can be used to create very realistic light settings. For example, a standard 100 watt incandescent bulb would only be approximately 2.0% efficient whereas a 25 watt compact fluorescent light will be 10% efficient. These will both produce around the same quantity of light in real life. This setting can also be connected to a texture to alter the color of the emitted light.
Is the wattage of the light source. Each light in the scene should be set to its real world wattage. This power will be multiplied by the texture input, where 1.0 means 100% of the power (so by default 0.025 means 2.5% gives 2.5W of light).
Controls the pattern of the light. An image texture or IES profile can be used as an emission pattern. Figure 3 shows the result of a Turbulence texture connected to the Emission pattern of a Blackbody Emission texture that has been applied to a sphere casting light on a plane below it. The texture appears in the light pattern cast on the plane. If Emission pattern is set to zero the texture will not cast light into the scene.
Allows users to choose which light sources will receive more samples. Adjusting the light source sampling rates in the scene will lead to a better balance between light sources. The sampling rate can also be set to 0 (zero), which means the emitter will be excluded from the direct light calculation.
Is useful when the brightness of the emitter is independent of the area of the surface. Enabling this option will cause emitters to keep the surface brightness constant independent of the emitter surface area.
Disabling this option will disable emission.This means the surface will not be visible in diffuse reflections, but still be fully visible in specular reflections. It will also be excluded from the direct light calculation.
Light Pass ID
Is used in conjunction with the Light Pass ID Render Element. Setting this value allows for rendering the contribution of the light in a separate render pass provided the Light Id pass of the same ID value is enabled in the Render Pass section of the OctaneRender settings.