The VRayLightRect, also known as the V-Ray Rectangle light or an "area light" is a planar light source. The light's shape can be set as a rectangle or a circular disc.
Color – Controls the color of the light. When using photometric units, this color is normalized so that only the color hue is used and the light intensity is determined by the Intensity.
Intensity – Multiplier for the light color; this is also the light intensity in the units set by the Units parameter.
Units – Choose the light units. Using correct units is essential when using the VRayPhysicalCamera. The light automatically takes the scene's unit scale into consideration to produce the correct result for the scale you are working with. The possible values are:
Default – The color and multiplier directly determine the visible color of the light without any conversion. The light surface appears with the given color in the final image when seen directly by the camera (assuming there is no color mapping involved). Lumens – Total emitted visible light power measured in lumens. When this setting is used, the intensity of the light does not depend on its size. A typical 100W electric bulb emits about 1500 lumens of light. lm/m/m/sr – Visible light surface power measured in lumens per square meter per steradian. When this setting is used, the intensity of the light depends on its size. Watts – Total emitted visible light power measured in watts. With this setting, the intensity of the light does not depend on its size. Keep in mind that this is not the same as the electric power consumed by a light bulb for example. A typical 100W light bulb only emits between 2 and 3 watts as visible light. w/m/m/sr – Visible light surface power measured in watts per square meter per steradian. When this setting is used, the intensity of the light depends on its size.
Is Disc – When enabled, the rectangle light has the shape of a planar disc.
U/V Size – Determines the width/height of the light measured in scene units. The width/height becomes twice this value.
Directional – When this value is 0, the light from the LightRectangle is spread out equally in all directions. Increasing this value makes the light beam more narrow and concentrates it in one direction.
Column
width
5%
Column
width
38%
Texture
...
Section
Column
width
57%
Use Texture – 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.
Rect Tex – Specifies the texture map when Use Texture is enabled. The light uses the texture's alpha as opacity map.
Texture Resolution – Specifies the texture resolution.
