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Lighting was redesigned using studio lights. These lights do not work in RenderMan prior to version 21.

Analytic Light

To add a light, select one of light tools such as Dome from the RenderMan Shelf which automatically creates a Pxr light OBJ.

We can also add a light via the TAB menu in OBJ pane. All the Pxr lights are listed under the Render TAB Menu.

Houdini 21 > Adding Light > pxrdomeobj.png

Light Transformation

You will notice some light's transformation components are hidden. This is because they are not applicable to that particular light type.

Light Name	Transformation
PxrRectLight	Translate, scale, and rotation.
PxrDiskLight	Translate, scale, and rotation.
PxrSphereLight	Translate, uniform scale, and rotation. If scaled non-uniformly it will render as a sphere anyway.
PxrDistantLight	Rotation only.
PxrDomeLight	Rotation only.
PxrPortalLight	Like a PxrRectLight, but you also need an external coordsys for the orientation of the dome texture itself.
PxrEnvDayLight	Rotation only.
PxrAOVLight	Since this is not a real light designed to illuminate, no translate, scale, and rotate.

Portal Light

You cannot have a portal light without parenting it to a dome light.

The PxrPortalLight is an optimized version of the dome light by looking through a "portal". To set up a PxrPortalLight OBJ, we need to parent it to a PxrDomeLight OBJ. A dome light can have more than one portal light as children.

Houdini 21 > Adding Light > portallights.png

Once it is parented to a dome light, RenderMan for Houdini will process the portal light specially according to the following rules:

Will inherit the parent dome's rotation depending on whether "Keep Position When Parenting" is selected when parenting it to the dome.
If a parameter is not local to the portal light, it will inherit from the parent dome light's setting for that parameter.
Intensity Multiplier will be multiplied by the parent dome's light Intensity.
Color Tint will be multiplied by the parent dome's Color.
It will apply all the dome's light filters as well as its own.

Mesh Light

To add a PxrMeshLight (using the geometry selected as the light source), select the mesh light tool from the RenderMan Shelf. This tool will ask you to pick an object for the mesh light. This is useful for creating things like extruded neon lights or fluorescent lighting with cylinders.