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Table of Contents
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Overview

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Plane, Disc, and Sphere lights are types of Area Light (VRayLight) objects. These are good general-purpose V-Ray lights for lighting scenes to simulate real-world light sources like lamps and ceiling lights.

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To create a Disc light, use one of the UI Paths for the Plane or Sphere light, then change the Type to Disc.

 

Sample Uses

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By default, V-Ray will render the light source if it is seen in the camera, as shown in the examples below. To render without seeing the light source, enable the light's lnvisible option.

Note: When a PlaneDisc, or Sphere light is visible in the rendering, aliasing at the edges of the light source can occur. Lens Effects such as the Bloom Effect (as used in the example images below) and Glare Effect are one way to hide the aliasing, while another is the use of a VraySoftBox map. For information on the cause of the aliasing and solutions for it, see Notes  below.


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Plane
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Plane lights rendering (with slight Bloom Effect)

 

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Sphere
lights as light bulbs in hanging fixture


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Sphere lights rendering (with slight Bloom Effect)

 

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Parameters - General Rollout

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Plane

 

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Disc

 

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Sphere

 

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Note: The size of the light source sometimes affects the light's intensity, shadows, and light diffusion depending on what is selected for the Units parameter. For more information, see Example: Light Units, Light Size and Shadow Crispness.

Units – Specifies the light units. Using correct units is essential when you work with the Physical Camera | VRayPhysicalCamera. 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:

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Res – Specifies the resolution at which the texture is resampled for importance sampling.


Parameters -  Rectangle/Disc Light Rollout

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This rollout is only available when the Type is set to Plane or Disc.

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Example: Light Source Size and Shadow Crispness


The following images show how the size of a Sphere light source affects shadows. Larger light sources produce blurrier shadows, while smaller light sources produce sharper shadows:

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Radius = 0.5; Units set to Luminous power (lm)

 

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Radius = 1.0; Units set to Luminous power (lm)

 

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Radius = 2.0; Units set to Luminous power (lm)

 

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Example: Light Size and Intensity


In the previous example, the light emitted by the light in all images is of the same intensity regardless of the light source's size. This is because the light's Units were set to Luminous power (lm), which doesn't depend on the light source size for intensity. Both the Luminous power (lm) and Radiant power (W) settings allow the light source to retain the same intensity regardless of the light source's size.

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Radius = 0.5; Units = Default (image)

 

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Radius = 1.0; Units = Default (image)

 

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Radius = 2.0; Units = Default (image)

 

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Options
Options

 

Parameters -  Options Rollout

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Exclude
– Opens the 3ds Max Exclude/Include window for selection of objects to be excluded or included in illumination and/or shadow-casting for this light.

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Double-sided – When the light is a Plane or Disc type, this option controls whether light is beamed from both sides of the light icon. This field has no effect for Sphere type of light source. For more information, see The Single-Sided vs Double-Sided Lights example below.

Invisible – Controls whether the shape of the light source is visible in the rendered image. When this option is disabled, the light source is rendered in the color specified by the Color or Temperature setting in the Intensity rollout. 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 reflections option.

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Skylight portal – When enabled, the light behaves as a portal or conduit for the environment behind it. As an example, this option is appropriate for an interior daytime scene, where a Plane light source could be placed in a window opening and directed toward the inside of a room. If the Skylight portal option is enabled for such a light, the light and color from the scene outside the window (including the environment map and any rendered objects) flows directly through the window opening and into the room. While an interior daytime scene is often sufficiently lit by a bright environment and GI alone, the Skylight portal option can be used to augment or brighten such lighting. With this option, the light takes its intensity and color from the environment behind it rather than from the Color and Multiplier parameters. For more information, see  The Skylight, Self-Illuminated Panels and VRayLights example  below.

Simple – Available only if the Skylight portal option is enabled. When this option is enabled, the portal will only use colors from the environment map and not from any scene objects behind the portal. When this option is disabled, the portal light takes its color from both the environment map and objects behind the light source. If this option is disabled, the light traces additional rays to render the objects, which might slow down the rendering. Enabling this option makes the rendering of portal lights faster.

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Affect reflections – Specifies whether the light source will appear in reflections.

 

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Example: Single-Sided vs Double-Sided Lights


This example demonstrates how a Plane light is affected when the Double-sided option on the Options rollout is enabled or disabled. The light is pointed away from the hallway.

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No decay
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No decay is enabled

 

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Example: Skylight, Self-Illuminated Panels and VRayLights

 

Here is an example of a simple room where the light comes from the environment. The scene was rendered in several different ways:

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In this example, using a VRayLight produces the best result in the shortest time. However, if you need to have many lights, this method can become quite slow because every single light needs to be sampled.

 

 

 

Parameters -  Sampling Rollout

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Subdivs – Controls the number of samples V-Ray takes to compute lighting for this light. Lower values mean more noisy results, but faster rendering. Higher values produce smoother results but take more time. Note that the actual number of samples also depends on the Global DMC Settings settings.

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Cutoff – Specifies a threshold for the light's intensity, cutting off the light's effect on a surface when it falls below this value. Lights lose intensity due to GI bouncing or decay. When light hits a surface but its intensity falls below the cutoff, the effect of the light on that surface 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 or reduce computations (and thus reduce rendering time) where the light's impact is negligible. Larger values limit the light's effect on objects to a smaller area around the light source, while lower values increase the range of the light's effect. If you specify 0.0, there is no cutoff and the light will be calculated for all surfaces regardless of intensity loss. The default value is 0.001.

 

Parameters -  Viewport Rollout

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Enable viewport shading – When enabled, the effect of the light is visible in the viewport.

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Icon text – Enables or disables the preview of the light name in the viewport.


Advanced Options Rollout

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This option does not generally need to be changed.

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Note: Disabling the Use MIS option might increase noise, especially in glossy reflections. Only disable it when you have a specific reason for doing so.

 

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Notes
Notes

Notes

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Fancy Bullets
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  • When using texture-mapped Plane lights, it is best to have GI enabled. This allows V-Ray to use combined direct and indirect sampling for the light, which greatly reduces the noise for surfaces close to the light.

  • The effect of all textured V-Ray lights can be shown through the Nitrous preview in the viewport.
  • When the Store with irradiance map option is check on any V-Ray Light it is then no longer treated as a direct light source and will not be available within the Light Select Render Element.
  • When an Area light is visible in a rendering, the edges of the light source can appear to be aliased. This happens because the light source color is usually very, very bright, far beyond the range of what an ordinary monitor can display, and antialiasing involves changing the colors of pixels at the edges of objects to a color midway between two other colors. When V-Ray applies antialiasing to a light source's edges, any colors midway between the light color and surrounding object colors are still very bright, beyond what a monitor can display, and the pixels that are supposed to provide a smooth transition from the light source to the surrounding objects appear to be the same color as the light source. As a result, there appears to be no antialiasing at all around the light source. To solve this problem, use a VRaySoftbox texture on the light source to cause its brightness to reduce at the edges, or use Lens Effects to soften and blur the aliased edges of the lights after rendering.