Light filters can be created in GafferThree.
To share a light filter, select the light filter, then the lights you wish to share it and right-click, choose Share Light Filters from the menu as shown below. The resulting light filter is then shared and display below each light.
Light filters created while a light is selected are automatically made children of the selected light.
Only lights with Cone Angle connected to Cookie and Barn filters have the option to match the light filter effect with the light's cone angle parameter.
All light filters have Viewer Modifiers that display the light filters in the Viewer. These Viewer Modifiers are helpful for approximating the shape and color of the light while setting up the light filters in the Viewer. For the Barn, Cookie, and Gobo light filters, you can use the Guide Size parameter in the viewer group at the bottom of the PrmanLightFilterCreate macro to adjust the length of the light filter projection guides.
The provided light filters also have Viewer Manipulators for interactively adjusting the light filter parameters in the Viewer.
If the physical Barn or Cookie position is perfectly aligned with the light position or positioned behind the light, barn or cookie guide lines will not be displayed. As you move the filter away from the light, the guides appear and become more focused.