Sphere Light

The Sphere Light is a V-Ray Light object in the shape of a sphere. It is a good general-purpose V-Ray light for illuminating scenes to simulate real-world point light sources such as lamp bulbs.

The sphere can be scaled to any size and emits light outward in all directions.

Certain parameters are only available as node inputs for the Light Sphere. 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.

Enabled – Enables the Sphere Light.

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

Color – Controls the color of the light when Color Mode is set to Color. 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 parameter.

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

Units – Dropdown to select light units. Using the correct units is essential when you are using the V-Ray Physical Camera. The light automatically takes the scene units scale into consideration to produce the correct result for the scale you are working with. 

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. Note that V-Ray uses a conversion unit of 683 lum/watt, that is, the maximum physical possible luminous efficacy.
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 using 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. Note that V-Ray uses a conversion unit of 683 lum/watt, that is, the maximum physical possible luminous efficacy.
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 – Multiplier for the light Color. this is also the light intensity in the units set by the Units parameter.

Radius – The radius of the light source, measured in scene units.

Sphere Segments – Controls the quality of the light object when it is visible either directly or in reflections. A bigger number makes the sphere smoother.

Invisible – Controls whether the shape of the light source is visible in the render result. When disabled, the source is rendered in the current light color. Otherwise it is not visible in the scene. Note that this option only affects the visibility of the light when seen directly by the camera or through refractions. The visibility of the light with respect to reflections is controlled by the Affect specular and Affect Reflections options.

Occlude Other Lights – Controls the behavior of the light, when Invisible is enabled, in relation to other light sources. When enabled, the invisible light blocks the lighting from other lights as if it's visible. Also in reflections the light behaves as if it's visible and occludes other lights. When disabled, the light is transparent for other lights and does not occlude them.

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

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

Affect Reflections – Determines whether the light appears in reflections of materials. This means both perfect and glossy reflections.

Affect Atmospherics – When enabled, the light influences the atmospheric effects in the scene. This option is not available with V-Ray GPU.

Diffuse Contribution – A multiplier for the effect of the light on the diffuse.

Specular Contribution – A multiplier for the effect of the light on the specular.

Atmospherics Contribution – Determines the amount of influence the light has on the atmospheric effects.

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 from the light; lower values make the light range larger. If you use 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 (default), the light casts shadows. Turn this option off to disable shadow casting for the current 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 render.

Shadow Color – Controls the color of shadows for this light. Note that anything different from black is not physically correct.

Caustics Subdivs – Used by V-Ray when calculating Caustics. Lower values mean more noisy results, but render faster. Higher values produce smoother results but take more time.

Caustics Multiplier – 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 render rollout section.

Near Decay On – Toggles near decay on and off.

Near Decay Start – Determines where the fade in starts. Anything before this point is rendered dark.

Near Decay End – Determines where the fade in ends. After this threshold, the light is at its full value.

Far Decay On – Toggles far decay on and off.

Far Decay Start – Determines where the fade off starts.

Far Decay End – Determines where the light reaches a value of 0, i.e. completely fades off. See the Far Decay End example for more.