Plane light with Directional = 0, 0.5, 1.0
Directional Preview = Always
The following This example shows the effect of the Directional parameter. Note that the plane light itself appears to turn black as the value gets closer to 1.0. This is due to the simplified directional distribution. The light is forced only in the forward direction, so the plane appears dark when viewing it from the side. This phenomenon does not occur with real-world lights because they exhibit more complex directional distribution.demonstrates how the light changes when Directionality value is changed, ranging from 0 to 1. When the value is closer to 1, the light is more focused towards one point, while when the value is closer to 0, the light spreads to all sides.
Parameters - Texture
Use Rect Tex – Enables the light to use a texture for the light surface. It is best to have GI enabled if there are surfaces that are close to a texture-mapped light. This allows V-Ray to use combined direct and indirect sampling for the light, reducing the noise for surfaces close to the light.
Parameters - Options
No Decay – Normally the light intensity is inversely proportional to the square of the distance from the light (surfaces that are farther from the light source receive less light than surfaces which are closer to the light). When this option is enabled, the light's intensity does not decay with distance. See the example under VRayLightSphere to see this demonstrated. This option is inactive when using the V-Ray CUDA engine.
Double Sided – When enabled, light emits from both sides of the plane. For more information, see the Single-Sided vs Double-Sided Lights example below.
Invisible – Controls whether the shape of the VRayLightRect source is visible in the render result. When this option is enabled, the light source is not visible in the rendering. When this option is disabled, if the light source is seen directly by the camera or through refractions, it appears in renderings in the current light color.
Note: The visibility of the light with respect to reflections is controlled by the Affect Specular and Affect Reflections options rather than the Invisible parameter.
Skylight Portal – When enabled, the Light Color and Intensity multiplier parameters are ignored; instead the light will take its intensity from the environment behind it. See the Skylight Portal example below.
Simple Skylight Portal – This option is available only when the Skylight Portal option is enabled. This option can speed up rendering by simplifying the process of tracing the environment for the skylight portal. When enabled, the VRayLightRect uses all the environment color, not just the color from objects behind the light. Using just the environment behind the light requires additional rays, so using the entire environment makes the rendering of portal lights faster.
Store with irradiance map – When enabled, and GI calculation is set to Irradiance map, V-Ray calculates the effects of the VRayLightRect and stores them in the irradiance map. The result is that the irradiance map is computed more slowly but the rendering takes less time. The irradiance map can also be saved for later use.
Affect Diffuse – Determines whether the light affects the diffuse properties of the materials.
Affect Specular – Determines whether the light affects the specular of the materials. This means glossy reflections.
Affect Reflections – Determines whether the light appears in reflections of materials, both perfect and glossy reflections.
Diffuse contribution – A multiplier for the effect of the light on the diffuse component.
Specular contribution – A multiplier for the effect of the light on the specular component.
This example demonstrates the use behavior of the light when Double Sided option with a rectangular light:
is enabled and disabled. When the Double Sided option is enabled, light is emitted from the two sides of the Rectangle light body.
Example: Skylight Portal
This example demonstrates the behavior of the Skylight Portal option. Generally, using the Skylight Portal option optimizes the render speed and the light in the scene. Notice how disabling this option produces much darker result inside the house.
Parameters - Sampling