Ambient Light

Certain parameters are only available as node inputs for the Light Ambient. For optimal editing, open the light in the V-Ray Node Editor. Follow these steps to see all the parameter locations for this node:

Click on the GIF to view it in full-size

This section describes the input sockets of the node. Some sockets have dedicated parameters, which are further described below, and some sockets are just inputs.

Transform – Allows a V-Ray Matrix node to be connected to determine the rotation and scale of the light.

Pivot Offset – Allows a vector-outputting node to be connected to control the pivot of the light. Alternatively, they can be set manually.

Color (input socket) – Overrides the color of the light, regardless if Color Mode is set to Color or Temperature.

Shadow Color (input socket) – Overrides the Shadow Color and allows a texture to be connected to control that property.

Intensity Tex (input socket) – Allows an integer-outputting node to be connected to control the Intensity.

Ambient Shade (input socket) – Allows an integer-outputting node to be connected to control the Ambient Shade.

Enabled – Turns the light on and off.

Color Mode – Determines how the color of the light is controlled, either Color or Temperature.

Color – Determines the color of the light.

Temperature – When the Color Mode is set to Temperature, this parameter controls the color of the light by degrees Kelvin.

Units – Specifies the light units. Using the correct units is essential when using the V-Ray Physical Camera. 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. When 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.

Intensity – A multiplier for the strength of the light.

Ambient Shade – Controls how the ambient light appears in the scene. A value of 0 shows light coming from all directions, while a value of 1 shows the light coming only from the direction of the light. A Texture can also be attached and blended with the Color using the Mix Strength parameter.

Affect Diffuse – Determines whether the light affects the diffuse properties of the materials.

Affect Specular – Determines whether light affects the specular of the materials. This means glossy reflections.

Affect Atmospherics – Determines whether the light influences the atmospheric effects in the scene.

Diffuse Contribution – When Affect Diffuse is enabled, a multiplier is specified for the effect of the light on the diffuse component.

Specular Contribution – When Affect Specular is enabled, a multiplier is specified for the effect of the light on the specular component.

Atmospherics Contribution – When Affect Atmospherics is enabled, this value determines the amount of involvement.

AreaSpeculars – When enabled, the highlights match the shape of the light. When disabled, highlights are always calculated as if affected by a point light.

Cut-off Threshold – Specifies a threshold for the light intensity below which the light is not computed. This can be useful in scenes with many lights, where you want to limit the effect of the lights to some distance around them. Larger values cut away more light; lower values make the light range larger. When this value is 0.0, the light is calculated for all surfaces.

LPE Label –  Allows a label to be assigned, which can be used to reference the light in a Light Path Expression. This is especially useful when working with the Light Select render element to evaluate custom light contribution in the scene.

Shadows – When enabled (the default), the light casts shadows. Disable this option to turn off shadows for the light.

Shadow Bias – Moves the shadow toward or away from the shadow-casting object (or objects). Higher values move the shadow toward the object(s), while lower values move it away. If this value is too extreme, shadows can "leak" through places they shouldn't or "detach" from an object. Other effects from extreme values include Moire patterns, out-of-place dark areas on surfaces, and shadows not appearing at all in the rendering.

Shadow Color – Controls the color of shadows for this light. Note that anything different from black is not physically correct. This option is inactive when using the V-Ray CUDA engine.

ShadowRadius – Specifies the size of the light. A value of 0.0 makes the light a point light. Larger values produce soft (area) shadows. 

Caustics Subdivs – Only used when calculating Caustics. Lower values mean more noisy results but render faster. Higher values produce smoother results but take more time.

Caustics Multiplier – This value is a multiplier for the generated caustics by the selected object. Note that this multiplier is cumulative - it does not override the multiplier in the Caustics settings.