USD Runtime Models

Evergine Runtime Models
Kitchen Set from Pixar Assets.

The Evergine.Runtime.USD NuGet package provides a powerful and efficient solution for dynamically loading USD models at runtime. It is designed for real-time 3D applications and integrates seamlessly into your Evergine projects.

Supported USD Features

The Evergine.Runtime.USD namespace includes a robust USD file loader that supports a comprehensive range of mesh and material features:

✅ Features

1. File Formats

  • Supports all Universal Scene Description formats: .usd, .usdc, .usda, and .usdz

2. Geometry

  • Vertices, indices, normals, and UVs (texture coordinates)
  • Supports:
    • Triangles, quads and N-gons (auto-triangulated)
    • Arbitrary polygon faces
    • Multiple mesh groups per file

3. Basic Materials

  • Supports UsdPreviewSurface as the standard material
    • Base color, specular, roughness, metallic, and emissive properties
    • Vertex color properties

4. PBR Materials

  • Fully compatible with Physically-Based Rendering (PBR)
  • Metallic–roughness workflow support
  • Advanced parameters supported if authored:
    • Clearcoat, clearcoat roughness, and specular IOR

5. Textures

  • Supports both embedded textures and external file references
  • Map types: base color, normal, metallic, roughness, emissive, occlusion and opacity
  • Compatible formats: PNG, JPG, BMP

6. Transparency

  • Automatically parses opacity and opacityThreshold inputs
  • Blend mode is configured based on material values

Limitations

1. Platform

  • The USD runtime is currently supported only on Windows desktop platforms.

2. USD File Handling

  • Very large USD files may not be readable in the current version.
  • Importing very large USD files may lead to increased memory consumption and reduced performance.

3. Animation Support

  • Animation data (e.g., skeletal or transform animations) is not yet supported in the current version.

⚠️ These limitations are subject to change in future updates.

Getting Started

To start using the Evergine.Runtimes.USD libraries, simply install the NuGet package and use the following code to load your assets:

protected async override void CreateScene()
{    
    var model = await USDRuntime.Instance.Read("MyModel.usd");

    var assetsService = Application.Current.Container.Resolve<AssetsService>();
    var entity = model.InstantiateModelHierarchy(assetsService);
    this.manager.EntityManager.Add(entity);
}

Custom Shader Support

By default, models are loaded using the Standard Effect (Evergine’s built-in shader). However, if you want to load models using your custom shader, you must pass an additional CustomMaterialAssigner function to the Read method:

protected async override void CreateScene()
{
    var assetsService = Application.Current.Container.Resolve<AssetsService>();

    var model = await USDRuntime.Instance.Read("Models/Kitchen_set.usd", this.CustomMaterialAssigner);

    var entity = model.InstantiateModelHierarchy(assetsService);
    this.Managers.EntityManager.Add(entity);
}

Samples

The USD Runtime has been extensively tested with the following publicly available datasets:

These tests help ensure compatibility with a wide range of real-world meshes, materials, and topology configurations. Below are several representative screenshots of models successfully loaded and rendered at runtime:

Sample screenshots

Kitchen Set – Pixar
Kitchen Set from Pixar Assets.

Toy biplane – Apple
Toy biplane, Copyright 2023 Apple Inc.

Armor - Sketchfab
The Parade Armour of King Erik XIV of Sweden. The Royal Armoury (Livrustkammaren).

Arm - Nvidia
Mechanic arms from Nvidia Omniverse USD Asset packages.