Lights¶
Lighting Overview¶
Lighting in Omniverse Kit based apps offers a wide variety of lighting options and capabilities. Here is a quick look at how you can expect to interact with and manage lighting.
Light Sources¶
Light sources in Kit based apps are made to realistically emulate real-world lights.
Light Types |
Realworld Equivalent
|
|---|---|
Distant Light |
Direct Sun/Moon light
|
Sphere Light |
Light Bulb
|
Rect Light |
Rectangular Panel Light
|
Disc Light |
Circular Panel Lights and Spotlights
|
Cylinder Light |
Neon/Fluorescent Light Tubes
|
Dome Light |
HDRI Skysphere (Background) lighting
|
Distant Light¶
Distant lights are parallel rays of light useful for showering an entire scene in a directional light. Meant to emulate lights infinitely far away, shadows cast with type of light will be hard edged and rather harsh compared to other lights. Ideal for Sun/Moon light, distant lights are generally a critical element to any outdoor scene.
Sphere Light¶
Sphere lights emit light in all directions from a central ball (not a point). The softness of the shadows (and overall intensity) are dictated by the radius of the central ball. Sphere lights are effective replacements for light bulbs.
Light Specific Properties |
Usage
|
|---|---|
Radius |
Source Sphere Radius
|
Treat as Point |
Makes the sphere size infinitely small
|
Rectangular (Rect) Light¶
Rectangular lights are capable of emulating light generated from a panel. The rectangle can be adjusted in width and length to accommodate any ratio from thin rectangle to square shape. This affect overall light power and shadow softness.
Light Specific Properties |
Usage
|
|---|---|
Height |
Depth of the light source (x value)
|
Length |
Length of the source (y value)
|
Disc Light¶
Similar to the rect light the Disc light emulates panel lighting but in the shape of a circle. Size is controlled by radius which affects overall light power as well as shadow softness. If shaping is used, the light acts as a traditional spotlight and has specialized controls to adjust the shape and color of the lights falloff.
Light Specific Properties |
Usage
|
|---|---|
Radius |
Source Disc Radius
|
Cone Angle |
Controls Projection Angle of the light. Higher is wider, lower is narrower.
|
Cone softness |
Increased the value to “soften” the lights cone edges.
|
Focus |
Higher Values soften and blends with Focus Tint
|
Focus Tint |
Tints the edges of the light falloff based on Focus
|
Note
Increasing Shadow samples per pixels in Rendering Settings smooths light falloff at the cost of render speed.
Cylinder Light¶
Tubular lighting useful in emulating neon/fluorescent light tubes and other linear omnidirectional lighting.
Light Specific Properties |
Usage
|
|---|---|
Radius |
Source Tube Radius
|
Length |
Source Tube Length
|
Dome Light¶
Used for image-based (background) lighting when supplied with a texture. Dome lights allow you to easily light your entire scene with a high or low dynamic range image.
Light Specific Properties |
Usage
|
|---|---|
Texture:File |
Low/High Dynamic Range image input
|
Texture:Format |
Selects Skydome Format
Choices include: LatLong, Angular, Mirrored Ball and Vertical Cross
HDR Formats: HDR, Exporter
LDR Formats: PNG
|
Common Light Properties¶
Common Light Properties |
Usage
|
|---|---|
Color |
The color of the light
|
Color Temperature |
The color of the light using the Kelvin Scale. (Not Supported Yet)
|
Diffuse Multiplier |
Adjusts the Diffuse Power of the light.
|
Enable Color Temp |
True uses Color Temperature for input, False uses Color. (Not Supported Yet)
|
Exposure |
Exposure offers a quick way to increase/decrease light intensity in stops.
|
Intensity |
Base luminosity of the the light source.
|
Normalize Power |
Brings light power into a normalized range.
|
Specular Multiplier |
Adjusts the amount specularity the light contributes to.
|
Light Linking¶
In Omniverse, Lights can be linked to surfaces allowing individualized response to specified lights.
Note
Light Linking is a specific utility of Path Tracing and only works in PT Mode.
USD Collections¶
The Omniverse USD Collections extension is required and is used to manage omniverse light linking. For instructions on creating and using collections, please see USD Collection Extension for additional details.
Property Panel Settings¶
Lights upon generation are set up for USD Collections. To investigate/edit, select a light and find the Collection properties in the property panel.
Option |
Result |
|---|---|
Light Link Include Root |
|
Light Link Expansion Rule |
|
Shadow Link Include Root |
|
Shadow Link Expansion Rule |