> [!abstract] Summary > Quick reference for the four USD file extensions — **`.usd`**, **`.usda`**, **`.usdc`**, **`.usdz`** — their trade-offs (ASCII vs binary, size, speed, human-readability) and when to use each. Includes how to convert between them. --- # File Extensions ### `.usd` — Binary or ASCII - Flexible format — can store either ASCII or binary content under the same extension. - Lets pipelines switch formats based on workflow requirements **without breaking asset references** (paths stay the same). ### `.usda` — ASCII - **Slower** to read. - **Larger** on disk. - **Human-readable** — can be opened in a text editor. - **Best for:** simple scenes or assets, debugging, version control. ### `.usdc` — Binary - **Faster** file reads. - **Small** file size. - **Not human-readable.** - **Best for:** large geometry, simulations, heavy production caches. **Optimal use cases for `.usdc`:** - Heavy geometry and animation caches. - Production asset libraries. - Performance-critical rendering workflows. - Large-scale scene assembly. - Final published asset delivery. ### `.usdz` — Packaged - A **self-contained archive** bundling USD content with all its dependencies. - Can contain `.usda`, `.usd`, images, audio, etc. - **Best for:** final delivery and handoff. --- ![[image-61.png]] # Convert Between Extensions ![[file-20241021190231536.png]] > [!tip] How to convert > See the practical step-by-step note: [[../USD Practice/USD Convert from USDC to USDA|USD Convert from USDC to USDA]]. --- # 🔗 Related - [[6.30 USD Theory]] — core USD concepts (layers, prims, stage, variants). - [[USD terms and definitions]] — glossary of USD concepts. - [[../USD Practice/USD Convert from USDC to USDA|USD Convert from USDC to USDA]] — how to run the conversion. - [[../USD Practice/USD Analysing usda files|USD Analysing usda files]] — reading `.usda` content. - [[USD MOC]]