Katana Developer Guide

Welcome to the Katana Developer Guide!

This collection of pages aims to provide you with an API reference, examples, and guidelines for developing scripts and plug-ins for Katana using Python, Lua, and C++. You can learn how to automate and customize workflows, processes, and the user interface, and how to integrate Katana with your pipeline.

If you’re new to Katana, you may want to have a look at the Glossary of Katana Terms first, to familiarize yourself with Katana-specific terminology.

We hope you’ll find what you’re looking for. If you have any questions, you can reach out to us via our Support website, the Foundry Community forums, or you can head over to the independently-hosted Katana Community Discord server.

Katana in a Nutshell

Katana is a node-based application, and provides a recipe-based approach to look development and lighting.

Katana project files store the descriptions of nodes and their parameters and ports, which are connected to form node graphs.

Katana node graphs are synced to create and configure graphs of operators (Ops) and their arguments (Op Args).

Ops are cooked using Katana’s Geolib to create locations and attributes of 3D scenes in a scene graph, ready for viewing and rendering.

In the end, It’s all just a bunch of Attributes.

Application

• CEL Reference
• Attribute Conventions
• Environment Variables
• Args Files
• External Software
• Copyright Notices
• Qt 5 to Qt 6 Migration Guide

Parameter Expressions

• Overview
• Python Expressions
• Reference Expressions

Scripting in Katana

• Working with Projects
• Working with Nodes
• Customizing Node Types
• Customizing the User Interface
• Rendering a Scene
• Cooking a Scene
• Callbacks and Events

Ops and OpScript

• Asset API
• Attributes
• Attribute Function
• Built-in Op Types
• Configuration
• Cook Interface
• Cook Interface Utilities
• Hints
• Look Files
• Material Resolve
• Op Args Builders
• Paths
• Resolutions
• Transformations
• ExpressionMath
• Imath
• pystring
• OpWrite

Writing Plug-ins

• The Plug-in System
• Native Plug-in Compatibility
• Asset Plug-ins
• Display Driver Plug-ins
• Renderer Plug-ins
• Default Attribute Producer Plug-ins
• Utilities
• Viewer Plug-ins
• Hydra Render Delegates
• Katana USD Plug-ins
• Look File Baking
• Material Soloing
• Render Farm Plug-ins

Performance

• Profile Results

Performance Optimization Guide

• Profiling and Optimization Guide: Start Here
• Designing Node Graphs for Optimal Performance
• Improving Op Performance
• Composing Concurrency-Friendly Scenes
• Improving OpScript Performance

USD Processing Engine

• Basic API Usage
• USD Processing Engine API
• USG Python API
• Engines
• KatanaToUsd
• UsdLayerExport
• UsdPythonWrite

API Reference

• C++ Header Index

• Python Module Index

• Lua Module Index