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PxrStdAreaLight

A Happy Buddha lit by a rect area light. Rendered with PxrVCM.

This is our standard geometric area light.

Input Parameters

Shape

Specifies the shape of the area light emitter.

Note: rman__Shape is not a real shader parameter. It is tracked by RfM or RfK to be output in the RIB stream. That means that you will have to relaunch your IPR in Maya / Live Render in Katana to see the changes.

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.

RIB: float exposure

Default: 0.0

Color

The color of the emitted light.

RIB: float lightColor

Default: | 1.0 1.0 1.0 |

Color Temperature

Enable Temperature

Turns color temperature on or off.

RIB: float enableTemperature

Default: 0

Color Temperature

Allow 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.

Defaults to 6500K, which should be very close to white on most monitors (D65 illuminant).

RIB: float temperature

Default: 6500

Emission Texture

Enable Emission Map

Enables / disables textured light emission.

RIB: float enableEmissionMap

Default: 0.0

Emission Map

A texture to define emitted light color.

RIB: string rman__EmissionMap

Default: ""

Linearize Color Map

Linearize the color map. This is only necessary for 8 or 16 bits textures. HDR textures are generally already in linear color space.

RIB: float linearizeEmissionMap

Default: 0

Color Map Resolution

This resolution only affects textured rect lights. To adjust the resolution of other textured lights, see the ShadingRate control above.

The Automatic option will result in using the size of the image specified in the Color Map parameter. If instead an image is specified in a network upstream from the Light Color, you should select a resolution.

RIB: float[2] rman__ProceduralResolution

Default: 1024 1024

Note: rman__ProceduralResolution is not a real shader parameter. It is tracked by RfM or RfK to be output in the RIB stream. That means that you will have to relaunch your IPR in Maya / Live Render in Katana to see the changes.

Scale S

Scales the mapping coordinates in the S direction on the light's surface.

RIB: float emissionMapScaleS

Default: 1.0

Scale T

Scales the mapping coordinates in the T direction on the light's surface.

RIB: float emissionMapScaleT

Default: 1.0

Offset S

Offsets the mapping coordinates in the S direction on the light's surface.

RIB: float emissionMapOffsetS

Default: 0.0

Offset T

Offsets the mapping coordinates in the T direction on the light's surface.

RIB: float emissionMapOffsetT

Default: 0.0

Components Weights

Specular Contribution

Scale the specular contribution of this light.

RIB: color specAmount

Default: | 1.0 1.0 1.0 |

Diffuse Contribution

Scale the diffuse contribution of this light.

RIB: color diffAmount

Default: | 1.0 1.0 1.0 |

Sampling

Light sampling is automatic, but you may occasionally have to override the allocated sample budgets to clean up noise in direct lighting.

Fixed Sample Count

Override the automatic sample allocation and use a fixed number instead. Negative values disable this feature.

RIB: float fixedSampleCount

Default: -1

Importance

Re-balance the automatic sample allocation. An importance of 2 will allocate twice the regular sample budget to this light.

This method is often preferable to Fixed Sample Count, as it only biases the automatic estimates.

RIB: float importance

Default: 1.0

Blockers

You can connect portals, blockers and gobos here.

Spotlight

Cone Angle

Spot cone angle in degrees.

RIB: float coneAngle

Default: 20.0

Penumbra Angle

Spot penumbra angle in degrees.

RIB: float penumbraAngle

Default: 5.0

Penumbra Exponent

Change the falloff of the penumbra.

RIB: float penumbraExponent

Default: 0.0

Light Profile

LatLong Emission Map

Name of the emission color map.

RIB: string profileMap

Default: ""

IES Map

Name of an IES light profile.

RIB: string iesProfile

Default: ""

Profile Range

Rescales the angular distribution of the IES profiles. Values less than 180 specify that the profile represents less angular coverage, and will effectively increase the size of the projected profile.

Defaults to -1 for full coverage / no scaling.

RIB: float profileRange

Default: -1

Profile Space

Specifies the space that the IES profile or emission color map is in.

RIB: string profileSpace

Default: "object"

Distribution Angle

Focusing power of the geometric area lights.

RIB: float distributionAngle

Default: 90

Distant

Angular Visibility

Specifies the size of the highlight as a angle. Only valid when Shape is set to distant.

Note: angularVisibility is not a real shader parameter. It is tracked by RfM or RfK to be output in the RIB stream. That means that you will have to relaunch your IPR in Maya / Live Render in Katana to see the changes.

Barn Doors

Enable Barndoors

RIB: float enableBarnDoors

Default: 0

Barndoor Top

The angle of the top flap.

RIB: float barnTop

Default: 0.0

Barndoor Bottom

The angle of the bottom flap.

RIB: float barnBottom

Default: 0.0

Barndoor Left

The angle of the left flap.

RIB: float barnLeft

Default: 0.0

Barndoor Right

The angle of the right flap.

RIB: float barnRight

Default: 0.0

Barndoor Texture

Barn doors are implemented as gobos, so they need a texture map. Ideally this would just be a black texture.

RIB: string barnDoorMap

Default: "default.tex"

Shadows

Enable Shadows

Enable ray-traced shadows.

RIB: float enableShadows

Default: 1

Shadow Color

The color of the shadows cast by emitted light.

RIB: color shadowColor

Default: | 0 0 0 |

Adaptive Shadows

Adaptively sample the lights shadows.

Conservative mode will trace a larger percentage of the shadow rays, which will result in less acceleration, but potentially higher quality shadows.

Aggressive will trace fewer rays, which can result in more significant speedups.

RIB: float adaptiveShadows

Default: 1

Shadow Max Distance

Limits the shadow distance. Any value smaller or equal to 0.0 will be ignored and the shadow distance will be unlimited. Defaults to -1 : unlimited shadow distance. Can be used to optimize shadow rays in very large scenes but may introduce artefacts if set too short. Use a small value with a white environment light to achieve a short-range ambient-occlusion look.

RIB: float shadowMaxDist

Default: -1

Shadow Trace Bias

Ray tracing bias for shadow computations. -1 uses the automatically computed bias value.

RIB: float shadowTraceBias

Default: -1

Shadow Subset

Set of geometry to consider for traced shadow intersection.

RIB: string shadowSubset

Default: ""

Don't Trace Subset

Set of geometry to ignore for traced shadow intersection.

RIB: string shadowExcludeSubset

Default: ""

Advanced

Normalize

When normalize is enabled, the amount of light contributed to the scene will not change as you scale the light source. This makes it easier to adjust highlight size without changing scene lighting drastically.

RIB: float areaNormalize

Default: 1

Light Group

The group is a special type of attribute which allows you to provide light category support for geometric area lights, as well as per group AOVs for the lighting on the surface.

Note: __group is a special parameter directly used by the lighting services.

Intensity

Linearly scales the light intensity. Exposure is more intuitive for area lights. Leave at 1.

RIB: float intensity

Default: 1.0