About Analytic Lights
One of the most valuable features of RenderMan for Katana (RfK) is the ability to create and manage Lights. The sections below provide a brief overview of how to take advantage of these capabilities.
Using RenderMan LightPackages
RfK offers PRMan-specific light packages for creating each type of light in GafferThree. These light packages minimize the amount of steps necessary to create a light. Shortcuts let you add a light with only one keystroke. Each light package also includes a set of light-specific attributes, available in the Object tab of GafferThree, which let you control certain attributes per-light without adding an additional PrmanObjectStatements node. The PxrMeshLight package includes the following attributes:
The analytic light packages only inclue Camera Visibility, which is set 'Off' by default, because the renderer ignores the other visibility attributes for analytic lights.
Creating Mesh Lights
There is a specific light package for creating mesh lights in GafferThree. To create a mesh light, select the desired geometry in the Scene Graph and add a "PxrMeshLight" in GafferThree. You can find a detailed explanation about mesh light setup in the link below:
Using Light Filters
Light filters are a powerful way to control a light's appearance. With Katana 2.0 or 2.1, light filters can be added to a scene with a PrmanLightFilterCreate node. GafferThree support for light filters is available in Katana 2.2 and above. You can find a detailed explanation about light filter setup in the link below:
Using Portal Lights
PxrPortalLight is an optimized environment light. Because Portals are lights, not light filters, they require a special workflow. GafferThree support for portal lights is coming in a future version of Katana. You can find a detailed explanation about portal light setup in the link below:
Light Sampling capabilities are available through sample balancing in the integrator, typically with the numLightSamples option. Or using the Importance multiplier on the Light Parameter list to draw more samples from the sample pool.