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Parameters

 

Basic

Intensity

Scales the contribution of this light linearly. This high dynamic range image (HDRI) has been edited where the sun is naturally bright and produces nice dark shadows and bright highlights. Notice that intensity 2.0 is quite bright in the sun! Other HDRIs with less range may benefit from values above 1.0.
 

Carousel Image Slider
includepxrDome_intensity05.jpg, pxrDome_intensity10.jpg, pxrDome_intensity20.jpg
maxNumber3
dotsfalse
columns3
infinitefalse
sliderHeight190
arrowsfalse
labelsFilterintensity
gutterSize20
titleIntensity
animatefalse
captionstrue

Exposure

Specifies the exposure of the area light as a power of 2. Increasing the exposure by 1 will double the energy emitted by the light source. A value of 0 produces an intensity of 1 at the source, -1 produces 0.5. Note this looks just like the above images. You may wonder why you might use Exposure, and the answer is that real world lighting has high energies and typical exposures are low values while you may have to type a really large number for equivalent Intensity. This is also comfortable to artists familiar with photographic measurements.

Carousel Image Slider
includepxrDome_intensity05.jpg, pxrDome_intensity10.jpg, pxrDome_intensity20.jpg
maxNumber3
dotsfalse
columns3
infinitefalse
sliderHeight190
arrowsfalse
labelsFilterexposure
gutterSize20
titleIntensity
animatefalse
captionstrue

 

Color

The color of the emitted light. If a color map is specified, this tints the color map. Below we have no map (defaults to white), red, and red tinting an HDRI. Note that tinting with a pure, saturated color may overpower textures as shown here.

Carousel Image Slider
includepxrDome_intensity05.jpg, pxrDome_intensity10.jpg, pxrDome_intensity20.jpg
maxNumber3
dotsfalse
columns3
infinitefalse
sliderHeight190
arrowsfalse
labelsFiltercolor
gutterSize20
titleIntensity
animatefalse
captionstrue

 

Color Map

Filename of the dome texture. Below are examples of different HDRIs used as the Color Map.

Carousel Image Slider
includepxrDome_intensity05.jpg, pxrDome_intensity10.jpg, pxrDome_intensity20.jpg
maxNumber3
dotsfalse
columns3
infinitefalse
sliderHeight190
arrowsfalse
labelsFiltermap
gutterSize20
titleIntensity
animatefalse
captionstrue

 

Map Gamma

Gamma-correct the texture. Each channel (RGB) can be adjusted independently.

 

Map Saturation
Adjust the saturation of the texture.

Enable Temperature

Turns color temperature on or off. Below we use the same Luxo/Pixar HDRI.

Carousel Image Slider
includepxrDome_intensity05.jpg, pxrDome_intensity10.jpg, pxrDome_intensity20.jpg
maxNumber3
dotsfalse
columns3
infinitefalse
sliderHeight190
arrowsfalse
labelsFiltertemperature
gutterSize20
titleIntensity
animatefalse
captionstrue

 

Color Temperature

Allows the user to choose the color temperature of the light in Kelvins. Unlike the basic light color, this allows the user to easily pick plausible light colors based on standard temperature measurements.This control will act like a filter or gel (a tinted transparent surface) in front of your light. If your light is white, you will get the chosen color temperature. If your light is colored, the color temperature will make it cooler (over 6500K) or warmer (below 6500K). 

 

Note

The effect will be less pronounced on fully saturated mono-chromatic lights.Defaults to 6500K, which should be very close to white on most monitors (D65 illuminant used by sRGB and Rec 709).

 

Primary Visibility

The light is directly visible to the camera by default. Turning this off makes it invisible to the camera.

 


Refine

The below options are non-physical controls used to art direct your images. For example: You could use a light with Diffuse Amount 0.0 to act purely as a source of highlights for your scene objects.


Specular Amount

Amount of specular light that is emitted. This is a non-physical control. You could use a light with Specular Amount 0.0 to act purely as a source of diffuse light for your scene objects and avoid adding highlights.

Carousel Image Slider
includepxrDome_intensity05.jpg, pxrDome_intensity10.jpg, pxrDome_intensity20.jpg
maxNumber3
dotsfalse
columns3
infinitefalse
sliderHeight190
arrowsfalse
labelsFilterspecularamount
gutterSize20
titleIntensity
animatefalse
captionstrue

 

Diffuse Amount

Amount of diffuse light that is emitted. This is a non-physical control. You could use a light with Diffuse Amount 0.0 to act purely as a source of highlights for your scene objects.

Carousel Image Slider
includepxrDome_intensity05.jpg, pxrDome_intensity10.jpg, pxrDome_intensity20.jpg
maxNumber3
dotsfalse
columns3
infinitefalse
sliderHeight190
arrowsfalse
labelsFilterdiffuseamount
gutterSize20
titleIntensity
animatefalse
captionstrue

 


Shadows

Note

All shadow parameters will be ignored if the light's  Trace Light Paths  is enabled in Advanced. The below options are all non-physical controls when used out of their default state. If  Trace Light Paths  is enabled then their physical nature is enforced.


Enable Shadows

Enable raytraced shadows.

Carousel Image Slider
includepxrDome_intensity05.jpg, pxrDome_intensity10.jpg, pxrDome_intensity20.jpg
maxNumber3
dotsfalse
columns3
infinitefalse
sliderHeight190
arrowsfalse
labelsFiltershadows
gutterSize20
titleIntensity
animatefalse
captionstrue

 

Shadow Color

The color of the shadows cast by emitted light.

Carousel Image Slider
includepxrDome_intensity05.jpg, pxrDome_intensity10.jpg, pxrDome_intensity20.jpg
maxNumber3
dotsfalse
columns3
infinitefalse
sliderHeight190
arrowsfalse
labelsFiltershadowcolor
gutterSize20
titleIntensity
animatefalse
captionstrue
0 0.


Shadow Max Distance

The maximum distance of the shadow starting from the position of the point being shaded. -1.0 is unset which will use the distance between the point being shaded and the point on the light. You may use this control to artificially reduce the distance shadows are cast. This may also increase render speed by not calculating shadows outside this distance. The below example uses a distance that prevents the statue from casting a shadow on the wall behind it while preserving other shadows.

Carousel Image Slider
includepxrDome_intensity05.jpg, pxrDome_intensity10.jpg, pxrDome_intensity20.jpg
maxNumber3
dotsfalse
columns3
infinitefalse
sliderHeight190
arrowsfalse
labelsFiltershadowdistance
gutterSize20
titleIntensity
animatefalse
captionstrue

 

Shadow Falloff

The distance from the light at which shadow falloff begins. -1.0 turns off shadow falloff. This is used along with Shadow Max Distance to create a false fade for shadows that are reduced or cut off by the Shadow Max Distance parameter. Below is an example with both parameters being used and the falloff is increased. Note this parameter may impact performance on complex lighting setups.

Carousel Image Slider
includepxrDome_intensity05.jpg, pxrDome_intensity10.jpg, pxrDome_intensity20.jpg
maxNumber3
dotsfalse
columns3
infinitefalse
sliderHeight190
arrowsfalse
labelsFiltershadowfalloff
gutterSize20
titleIntensity
animatefalse
captionstrue

 

Shadow Falloff Gamma

The gamma of the shadow strength in the falloff zone. This requires the use of Shadow Max Distance and Shadow Falloff. The falloff is more obvious as the value decreases.

Carousel Image Slider
includepxrDome_intensity05.jpg, pxrDome_intensity10.jpg, pxrDome_intensity20.jpg
maxNumber3
dotsfalse
columns3
infinitefalse
sliderHeight190
arrowsfalse
labelsFiltershadowfalloffgamma
gutterSize20
titleIntensity
animatefalse
captionstrue

 

Trace Subset

Set of geometry to consider for traced shadow intersection. If this is not specified, all geometry are considered for traced shadow intersection.


Don't Trace Subset

Set of geometry to ignore for traced shadow intersection. If this is not specified, all geometry is used for traced shadow intersection.

 

 


Advanced

 

Trace Light Paths

Enable light and photon tracing from this light. This value enforces a physically-based light and as a side-effect disables the above Shadows controls. Users may use this feature to selectively decide which lights emit photons when using the PxrVCM or PxrUnified Integrators.


Thin Shadow

Enable thin shadow and disable refraction caustics for this light. This parameter will ignored if Trace Light Paths is enabled. This is a non-physical control that creates "fake" colored shadows for transmissive objects without needing to generate photons for caustics. Below we go from On (default) to Off (opaque shadowing). Notice we lose the colored shadows and interior colored reflection choosing Off, but we gain some render speed instead.

Carousel Image Slider
includepxrDome_intensity05.jpg, pxrDome_intensity10.jpg, pxrDome_intensity20.jpg
maxNumber3
dotsfalse
columns3
infinitefalse
sliderHeight190
arrowsfalse
labelsFilterthinshadow
gutterSize20
titleIntensity
animatefalse
captionstrue

 

Visible in Refraction

Make a light visible through transmission effects like glass and windows by turning this on.

 Cheap Caustics

Manifold Walk

Used with the PxrUnified Integrator and enabling Enable Manifold Walk to create inexpensive caustics. Note: You must disable Thin Shadows

 

Light Samples

Specifies an override of the number of light samples to be taken for this light source. If set to something other than zero, it will override the sampling performed by the integrator. It's recommended to leave this at the default unless you experience unsolvable noise from the light.


Light Group

Specify the light group name used for light group LPEs. This is useful to generate per-light AOVs for later adjustment in compositing.

 

Importance Multiplier

Rather than setting explicit Light Samples, users can change the amount of samples the light will be assigned internally by changing this value. RenderMan creates a set of samples at render time for all lights in the scene and changing this value rebalances the samples across the lights. Note that increasing this value will cause more samples to be selected from this light while reducing it for others in the scene. Lower than the default will decrease the samples while providing more to others in the scene.

 

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