# Learn OpenUSD: What Is Hydra?

**Channel:** NVIDIA Omniverse
**Source:** https://www.youtube.com/watch?v=BfWvZ0w4yMM
**Transcript page:** https://www.withtranscript.ai/video/BfWvZ0w4yMM

## Chapters

- 0:01 — Introduction to Hydra in OpenUSD
- 0:55 — Hydra Scene Flow and Decoupling
- 1:48 — Render Delegates and Hydra Tools
- 2:47 — Lesson Recap and Resources

## Transcript

**[0:01]:** in this lesson we'll explore Hydra a powerful rendering architecture within open USD understanding Hydra enables efficient and flexible rendering of complex 3D scenes Hydra is a rendering architecture within open USD that provides a high performance scalable and extensible solution for rendering large 3D scenes it serves as a bridge between the scene description data such as USD and the rendering back end the open and extensible nature of open USD means it supports many different renderers like Arnold and renderman and open usds included hydrostorm renderer offers a simple way for developers to visualize data out of the box it has three main parts a scene delegate which provides the scene information the render index which keeps track

**[0:55]:** of changes and manages the scene and the render delegate which uses both the render index and the scene delegate to visualize scene information to create the final image Hydra operates on one or more Scene delegates which is a hierarchical representation of the scene data it processes the scene delegates into an abstract renderable scene which the render delegates can use to generate rendering instructions tailored for the specific rendering backend this approach decouples the scene data from the rendering backend allowing o for flexibility and extensibility Hydra supports various render delegate plugins enabling developers to create custom rendering backends or extend existing ones open USD ships with HD storm a realtime rasterizer render delegate with open GL metal

**[1:48]:** and Vulcan implementations HD storm is leveraged by USD View and many other tools Hydra also ships with HD tiny and HD Embry which can be used as examples of how to implement render delegates understanding Hydra enables efficient and flexible rendering of complex 3D scenes in this lesson we learned Hydra is a rendering architecture within open USD that Bridges scene data and rendering backends it operates on a scene delegate and enables render delegate plugins to generate rendering instructions for specific backends Hydra supports various rendering back and techniques including rasterization and Ray tracing it provides extensibility through plugins and custom rendering backends and developers can interact with Hydra using python bindings with its support for various rendering

**[2:47]:** techniques extensibility and decoupling of scene data from rendering backends Hydra empowers users to create work in large scenes we encourage you to explore Hydra further and leverage its capabilities in your open USD projects thanks for watching check out the following resources and we'll see you in the next lesson