Lights

Overview

Lighting in LumenRT for NVIDIA Omniverse 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.

These light sources are made to realistically emulate real-world lights

Table 1. Light Types and their Real world Equivalent
Light Types	Real World Equivalent
Distant Light	Direct Sun/ Moon Light
Sphere Light	Light Bulb
Rect Light	Rectangular Panel Light
Disc Light	Circular Panel Lights ans Spotlights
Cylinder Light	Neon/Fluorescent Light Tubes
Dome Light	HDRI Skysphere ( Background) lightning

Setting	Description
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: 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: 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: 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: 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: Texture > Files: Low/High Dynamic Range image input Texture > Format: Selects Skydome Format. Choices include : LatLong, Angular, Mirrored Ball and Verical Cross ; HDR Formats: HDR ; ExporterLDR Formats: PNG

Common Light Properties

Properties	Usage
Color	The color of the light
Color Temperature	The color of the light using the Kelvin Scale
Diffuse Multiplier	Adjust the Diffuse Power of the light
Enable Color Temp	True uses Color Temperature for input, False uses Color
Exposure	Exposure offers a quick way to increase/ decrease light intensity in stops
Intensity	Base Luminosity of the light source
Normalize Power	Brings light power into a normalized range
Specular Multiplier	Adjusts the amount specularity the light contributes to