CEL in the User Interface

In the UI, a standard CEL Widget interface is provided for CEL expressions. For your convenience, this allows you to build CEL expressions out of three different types of components (called statements):

• Paths – these are explicit lists of scene graph paths. If you drag and drop locations from the Scene Graph tab onto the Add Statements area of the CEL widget you are automatically given a CEL expression that based on those paths.

• Collections – a pre-defined named collection of scene graph locations. Essentially these are arbitrary sets of locations that are handed off for use downstream in the pipeline. Collections can be created in a Katana scene using the CollectionsCreate node, and can also be passed from one Katana project to another using Look Files.

• Custom – these allow complex rule based expressions, such as using patterns with wildcards in the paths, or 'value expressions' that specify values that attributes must have for matches.

CEL expressions can also be built out of combinations of these components using union, difference, and intersection operations.