Katana for Technical Artists | Cel Statements
Instructor
Adam Davis
Level
Experienced
Length
29m 44s
Version Required
Katana 4.0 and later
Introduction to CEL and Graph State Variables:
In this video, Adam will introduce you to Collection Expression Language (CEL) in the context of Graph State Variables (GSVs) within a multi-shot scene.
You’ll cover how to set up both local and global Graph State Variables while using the Katana variable nodes - VariableSwitch, VariableSet, VariableDelete, and VariableEnabledGroup.
Adam uses these key concepts of GSVs to demonstrate how CEL statements can be used to make complex scene graph location selections for setting up render layers or adding lights for specific shots and passes.
Advanced CEL Use Cases:
In this video, you’ll learn some more advanced methods of constructing CEL statements for complex selections, focusing on how CEL can be used to give more control when working with complex scenes and how to ensure you’re working efficiently. Adam demonstrates how to make use of the CEL Scratch Pad panel to test the resulting selections of CEL statements.
You’ll start by looking into making selections by name and wildcard (*) syntax and combining these selections using the union (+) and difference (-) syntax. Adam will then demonstrate how these selections can be made more efficiently by using Value Expressions & Regular Expressions (Regex). By using this different syntax, you can make the same complex selections much more concise by combining them into just one expression.
Regex also makes it easy to specify scene graph locations despite any potential naming irregularities, such as character case, and Adam will cover how these expressions can be constructed.
Finally, you’ll take a look at how to make selections based on objects with certain attributes using the hasattr syntax, as well as how to improve search efficiency by only searching the Scene Graph to a particular point, for example, to the first instance component level.
In this video, Adam will introduce you to Collection Expression Language (CEL) in the context of Graph State Variables (GSVs) within a multi-shot scene.
You’ll cover how to set up both local and global Graph State Variables while using the Katana variable nodes - VariableSwitch, VariableSet, VariableDelete, and VariableEnabledGroup.
Adam uses these key concepts of GSVs to demonstrate how CEL statements can be used to make complex scene graph location selections for setting up render layers or adding lights for specific shots and passes.
Advanced CEL Use Cases:
In this video, you’ll learn some more advanced methods of constructing CEL statements for complex selections, focusing on how CEL can be used to give more control when working with complex scenes and how to ensure you’re working efficiently. Adam demonstrates how to make use of the CEL Scratch Pad panel to test the resulting selections of CEL statements.
You’ll start by looking into making selections by name and wildcard (*) syntax and combining these selections using the union (+) and difference (-) syntax. Adam will then demonstrate how these selections can be made more efficiently by using Value Expressions & Regular Expressions (Regex). By using this different syntax, you can make the same complex selections much more concise by combining them into just one expression.
Regex also makes it easy to specify scene graph locations despite any potential naming irregularities, such as character case, and Adam will cover how these expressions can be constructed.
Finally, you’ll take a look at how to make selections based on objects with certain attributes using the hasattr syntax, as well as how to improve search efficiency by only searching the Scene Graph to a particular point, for example, to the first instance component level.