# Summary **USD at Scale** describes how the animation and VFX studio Animal Logic integrated Pixar’s Universal Scene Description (USD) into their large legacy pipeline to improve productivity and support multiple feature films simultaneously. ### Key Points: - **Background:** Previously, Animal Logic used a generative, database-driven approach with heterogeneous assets and many file formats. An in-house Common Scene Description was attempted but abandoned. After Pixar open-sourced USD in 2016, Animal Logic began a phased rollout starting with a pilot on *Peter Rabbit* (2018), then a full migration on *Peter Rabbit 2* (2021), continuing on subsequent projects. - **Architectural Choices:** - **Fragment-Based Composition:** Inspired by the Entity-Component-System pattern, assets are built from reusable "fragments" (USD files representing units of functionality like geometry or rigging). Entities (characters, props, shots) reference these fragments, enabling reuse and reducing complexity. - **Entity-Based Composition:** Some fragments can reference entities to support assemblies like environments or shot breakdowns. - **Entity Domains:** Entities are organized into domains reflecting workflows (Modeling, Rigging, Surfacing), mapping to departments and clarifying responsibilities. - **Technical Variants:** Heavy payload data is separated into technical variant files (USD or other formats), referenced via USD variant sets. - **Packaging:** USD files are snapshotted with versioned identifiers to create packaged assets, supporting different package states (Live, Delivered, etc.) and flexible workflow needs. - **Implementation:** - Developed the **LEAF Toolkit** (Python libraries) to create and edit USD files following the entity-fragment model. - Built the **AssetWorkshop Toolkit** with UI tools for artists and TDs to view and edit USD graphs interactively. - Created the **VirtualBreakdown Toolkit** for higher-level logical views of assets and efficient handling of large numbers of entities. - **Migration Milestones:** - Prototype USD pipeline on *Peter Rabbit* animation. - Technical migration and rollout on *Peter Rabbit 2*, including new artist tools. - Workflow migration on *DC League of Super-Pets*, upgrading tools to natively use USD. - Ongoing enhancements on recent and upcoming projects, including new tools like Modeling Studio. - **Discussion:** - USD content is reusable and can be consumed by any USD-aware system. - The entity-fragment model provides explicit, validated asset combinations. - Content creation is decoupled from the production database, allowing artists to experiment without cluttering the database. - The migration unified workflows, improved toolsets, clarified departmental contributions, and eased onboarding due to USD’s industry adoption. - **Future Work:** - Optimizing asset resolution and reducing the number of generated files, especially for cloud workflows. - Developing tools for large-scale asset updates and visual programming for TDs. - Improving caching for faster lookups of USD relationships. - Enhancing quality assurance to validate domain contributions and prevent breaking changes. --- ![[USD-at-Scale.pdf]]