Universal Scene Description (OpenUSD) is an open, extensible framework and ecosystem with APIs for composing, editing, querying, rendering, collaborating, and simulating within 3D virtual worlds.This post explains how you can start using OpenUSD today with your existing assets and tools and what steps you can take to iteratively up-level your USD workflows. For an interactive, comprehensive introduction to the essential concepts, vocabulary, and best practices for OpenUSD, explore the free Learn OpenUSD learning path from the NVIDIA Deep Learning Institute.Data exchangeOpenUSD does not replace your existing tools or data formats. As the name suggests, Universal Scene Description provides a common way to represent data for many 3D concepts such as meshes and PBR materials. It continues evolving to support additional concepts such as physics and B-reps. Figure 1. OpenUSD’s growing ecosystem of DCC applicationsTo begin using OpenUSD with your existing assets, use an exporter or converter to bring your content into USD. This approach ensures swift and effective integration into new USD workflows. By using USD in this way, you can begin to enhance collaboration, performance, and interoperability across different stages of production.For more information about how to get started, see the list of applications and tools that support USD interchange.As you expand your USD workflows and want to use OpenUSD with proprietary data, you may have a need to develop your own data exchange solutions. Data exchange pipelines manage the extraction, transformation, and ingestion of content from one data format to another. There are several primary types of data exchange solutions used to integrate existing content into USD workflows:Importers and exporters: These are found in digital content creation (DCC) applications and enable you to directly import and export 3D assets to and from USD. Popular software like Rhino and Blender facilitate the importing of 3D assets, while applications like Houdini open 3D assets as native USD files.This makes it straightforward to work with USD within your existing tools.Converters: These are standalone programs or scripts designed to convert 3D files from various formats to and from USD. They offer flexibility for batch processing and automation, ensuring that your assets can be easily transformed without the need for manual intervention.USD file format plug-ins: This type of USD plug-in enables you to keep your data in its original source format while dynamically reading and translating it to USD on the fly when you open a stage. This means you can work with your assets in their native formats and still benefit from USD’s powerful features, while maintaining data integrity and workflow efficiency.Conceptual data mapping and extract, transform, load (ETL) are crucial processes for developing data exchange solutions that help ensure the seamless transfer and integration of 3D assets and data. Conceptual data mapping involves defining how data from one system or format corresponds to data in another system or format. This is particularly important when working with different DCC applications or file types, as each may have its own unique data structure and representation. ETL is a more comprehensive process used to move and integrate data from one system to another. It consists of the following main steps:Extract: Pull data from the source system or file format. The data could be 3D models, textures, animations, or any other relevant content.Transform: Transform extracted data to fit the target runtime requirements. This might include converting units, reformatting data structures, or filtering out irrelevant or private data.Load: Load the transformed data into the target runtime. This is sometimes called ingestion and ensures that the data is ready for use in USD-based workflows and applications.Conceptual data mapping and ETL processes are essential for ensuring that content can be effectively and accurately transferred into the USD ecosystem, maintaining its quality and functionality throughout the exchange. The OpenUSD Exchange SDK can help accelerate the development of data exchange solutions and help with authoring high-quality OpenUSD data.After getting your data into OpenUSD, the next step is understanding how to aggregate and structure it for maximum efficiency.Learn how to develop data exchange pipelines with the free Learn OpenUSD self-paced curriculum.Asset structure principles and content aggregationWell-structured assets unlock effective content aggregation and asset reusability—this is where OpenUSD truly excels. Proper asset structuring and content aggregation are key methods for efficiently organizing and combining 3D assets and scenes in complex projects.Developing an asset structure involves breaking down your 3D content into smaller, manageable components that can be easily referenced and reused. This enables you to create a hierarchical and organized structure that simplifies the management and maintenance of your assets. This approach both improves reusability and performance by enabling you to load only the necessary components when needed. With a well-designed asset structure, you can enhance collaboration as different workstreams can author data independently in separate layers, which can then be composed into a single asset. This non-destructive editing approach ensures that changes made by one team do not overwrite another team’s work.After you’ve built your smaller components, use content aggregation to combine them into a single cohesive scene. Composition arcs, such as references and payloads, support this process.These techniques help make OpenUSD a powerful tool for managing large-scale 3D projects, facilitating efficient collaboration, asset reuse, and pipeline efficiency, making it an indispensable part of any modern 3D production workflow.Learn asset structuring principles and content aggregation with the free Learn OpenUSD self-paced curriculum.Composition arcsComposition arcs are the foundational operators of OpenUSD that combine smaller units of scene description into larger units. This enables robust asset structures and content aggregation in OpenUSD workflows. This feature is one of the superpowers of OpenUSD, setting it apart from other 3D data formats and frameworks.Figure 3. Composition arcs enable the creation of complex 3D objects such as autonomous mobile robotsComposition arcs are essential tools for non-destructively combining units of USD data. The composition arcs available in OpenUSD include sublayers, references, payloads, variant sets, inherits, specializes, and the most recent addition, relocates. Start with the following composition arcs to gain an understanding how you can leverage them in your own workflows:Sublayers: Enable multiple collaborators or processes to operate on a given USD context. The data authored in a sublayer is added to a USD context in an “include” fashion.References: Most suited for content aggregation and can be used to graft one USD context onto the hierarchy of another USD context. By referencing assets, you can maintain a single source of truth for each component, ensuring consistency and reducing redundancy. This is particularly useful in large-scale projects where the same assets are used repeatedly.Variant sets: Used to store multiple variations of a component, enhancing adaptability without duplicating data. This feature enables you to create different versions of an asset, such as different materials or configurations, all within a single, efficient structure. Use cases include specifying different textures and materials or configurations of a model, such as describing a car featuring different paint colors or with different rim styles.Figure 4. Composition of an OpenUSD sceneLearning and implementing composition arcs will provide immediate value to your USD workflows. However, achieving mastery can take years due to their extensive flexibility and diverse applications. To use OpenUSD effectively, we highly recommend investing significant time in experimentation and refining your understanding of composition arc types. Learn to create composition arcs with the free Learn OpenUSD self-paced training.Get startedOpenUSD offers a comprehensive set of features for efficient 3D asset management and content aggregation, making it an indispensable framework for large-scale projects. By mastering data exchange, asset structuring, and composition arcs, you can significantly improve collaboration, performance, and reusability in your 3D workflows.Build on your foundational knowledge with courses on the Learn OpenUSD learning path.Start developing with OpenUSD on the Omniverse Kit SDK and generative AI models for OpenUSD development through USD NIM microservices.For more resources on OpenUSD, explore the Alliance for OpenUSD (AOUSD) forum and visit the AOUSD website.
