Creating Composition Arcs#

A Note About LIVERPS vs LIVRPS

OpenUSD recently introduced a new composition arc called “relocates,” which is now included in the strength ordering acronym. What was previously known as LIVRPS is now LIVERPS, with the “E” representing rElocates. Learn OpenUSD will be updated soon to cover relocates, but for now, please note that you may see both LIVRPS and LIVERPS used interchangeably.

This module, Creating Composition Arcs, is designed to equip you with the knowledge and skills necessary to effectively use OpenUSD’s composition arcs to create and manage complex 3D scenes. You’ll learn how to leverage various composition techniques to build flexible and efficient USD workflows, improving interoperability between different 3D applications and formats.

Throughout this module, you’ll explore the fundamental concepts of USD composition, including layers, sublayers, references, payloads, variant sets, inherits and specializes. You’ll engage in hands-on exercises using usdview and Python scripting to create, manipulate and analyze USD scenes, gaining practical experience in applying these concepts to real-world scenarios.

This module is designed for those with experience in 3D graphics and OpenUSD, providing you with the knowledge and skills to effectively use OpenUSD in your workflows. We encourage you to actively participate in the exercises to enhance your learning experience.

Learning Objectives#

By the end of this module, you’ll be able to:

  • Implement layers and sublayers to organize and structure USD scene data effectively.

  • Create and manage references and payloads to build modular and efficient USD scenes.

  • Apply proper encapsulation techniques.

  • Design and implement variant sets to create flexible asset variations within USD scenes.

  • Utilize inherits and specializes arcs to create hierarchical relationships and optimize scene composition.

  • Apply LIVRPS strength ordering rules to predict and control USD composition results.

  • Debug and troubleshoot complex USD compositions using usdview and Python.

Module Outline#

This module contains the following lessons:

Prerequisites#

Completion of all modules in the Learn OpenUSD: Foundations curriculum.

An understanding of fundamental programming concepts in Python such as functions, loops, dictionaries and arrays and Python related libraries. Understanding of OpenUSD concepts and basic OpenUSD APIs.

Tools, Libraries and Frameworks Used#

OpenUSD