This page provides information on the V-Ray Spot Light.
Overview
The V-Ray Spot Light is a V-Ray specific light source that can be used to create a physically accurate light that directs a narrow beam of light with falloff.
UI Path: ||obj Network|| > V-Ray > V-Ray Spot
Main
These parameters can be found in the V-Ray Light tab of the parameters editor.
Use Intensity Texture – When enabled, replaces the Intensity parameter with a float texture slot that will override the Intensity.
Intensity – Multiplier for the light strength; this is also the light intensity in the units set by the Units parameter.
Use Color Texture – When enabled, allows the specification of a texture for the Spot Light. If used, it will override the Color parameter.
Color – Specifies the color of the Spot Light.
Cone Angle – Specifies the angle of the light cone formed by the V-Ray Spot Light.
Penumbra Angle – Specifies the angle within the light cone at which the light begins to transition from full strength to no lighting. When set to 0, there is no transition and the light produces a harsh edge.
Penumbra Falloff Type – Determines how the light will transition from full strength to no lighting inside the light cone.
Linear – The light will not have any falloff.
Smooth Cubic – The light will fade in a realistic way, similar to the Inverse Square option for Decay.
Dropoff – Controls the dropoff rate of the light intensity.
Decay – Controls the behavior of the light intensity from the distance of the light source.
Barn Door – Enables or disables the barn door effect. Barn doors restrict the light cone on the four sides of the light to produce a rectangular light shape. In the real world, barn doors are four planes attached in a square around the light.
Use Decay Regions – Enables decay regions to be used with the V-Ray Spot Light.
Units – Specifies the light units. Using correct units is essential when using the V-Ray Physical Camera. The light will automatically take 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 will appear 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 will 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. With 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.
Use Global Light Level – When enabled, the light will use the global light level setting.
Shadows
Enabled – When enabled, the light casts shadows. Disable this option to turn off shadows for the light.
Use Shadow Color Texture – When enabled, allows the specification of a texture for the shadows for this light. If used, it will override the Color parameter of the Shadows rollout.
Color – Controls the color of shadows for this light. Note that anything different from black is not physically correct.
Radius – Specifies the size of the light. A value of 0.0 makes the light a point light. Larger values will produce soft (area) shadows.
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.
Subdivs –Controls the number of samples for the area shadow of the Spot Light. Higher values produce area shadows with better quality but render slower. Note that this parameter is available for changing only when Use local subdivs is enabled in the DMC Sampler.
Shadow Mask – Specifies a texture for the shadows for this light. If used, it will override the Color parameter of the Shadows rollout.
Advanced
Area Speculars – When enabled, the highlights will match the shape of the light. When disabled, highlights will always be calculated as if affected by a point light.
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.
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.
MoBlur Nsamples –Specifies the number of samples used to sample the light for motion blur.
Cut-off Threshold – Specifies a threshold for the light intensity, below which the light will not be 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 of the light; lower values make the light range larger. When this value is 0.0, the light is calculated for all surfaces.
Bumped Normal Check – When enabled, the bumped normal is used to check if the light direction is below the surface.
Use Multiple Importance Sampling – Enables of disables Multiple Importance Sampling (MIS) for the light. When MIS is enabled (the default), the light's contribution is split between direct illumination on the one hand, and GI (for diffuse materials) or reflections (for glossy surfaces) on the other. This means that portions of the light's contribution will end up in the GI render elements (or the reflection render elements respectively). In certain specific situations this is undesirable and this option can be used to always calculate the light contribution through direct illumination.
GI
Store With Irradiance Map – When this option is enabled and GI calculation is set to Irradiance map, V-Ray calculates the effects of the V-Ray Spot Light 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.
Diffuse Multiplier – A multiplier for the diffuse photons.
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 tab of the V-Ray Render Settings.
Photon Subdivs – Only relevant when calculating the Global Photon Map. Lower values mean noisier results and faster rendering. Higher values produce smoother results but take more time to render.
Caustics Subdivs – Only used when calculating Caustics. Lower values mean more noisy results, but will render faster. Higher values produce smoother results but take more time.