Guidelines for Structuring USD Assets

[Carlosan]

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Overview

The goal of this guide is to provide artists and pipelines a good starting point for structuring reasonable and featureful USD assets. It is not necessarily trying to provide a strict specification, but rather define some terms and expectations for building tools and workflows around the “minimum viable” USD assets.

This document also hopes to accelerate some intuition around USD assets, by providing a good base to start working in USD, without requiring extensive USD research or knowledge up front. Nothing replaces experience, but we hope to accelerate your experience.

Many studios, artists, and productions will want and need flexibility in structuring their assets. It is important to provide some core concepts that artists, TDs, managers, coordinators, and developers can use when talking about USD assets. The following concepts and descriptions should be common enough for any asset structures in any USD pipeline.

• Models are assets in USD. Published models use the component or assembly model kind, or kinds based on those.
• Component models are publishable assets that keep their geometry behind a payload; they are generally self-contained (apart from materials referenced from a global library).
• Assembly models are publishable assets which reference components or other assembly assets. Assemblies that generate their own Components should payload those components and ensure correct model hierarchy. Group kind is used only to organize assemblies and maintain model hierarchy.
• Published component and assembly models should inherit from a class primitive.

Some of these terms may have existing meaning within pipelines and workflows. This can make discussions and decisions difficult for artists and developers. However, using these terms consistently across tools and studios will accelerate the learning curve for everyone involved.