NVIDIA OpenUSD Professional - Fact Sheet¶

Quick Reference¶

Exam Code: NCP-USD Duration: 120 minutes Questions: 60-70 questions Passing Score: Not officially published Cost: $200 USD Validity: 2 years Difficulty: Advanced

Exam Domains¶

Domain 1: USD Fundamentals¶

Core Data Model¶

Prims (Primitives): - Fundamental scene element in USD - Hierarchical (tree structure like a file system) - Types: Xform, Mesh, Camera, Light, Scope, Material - Each prim has a unique path (e.g., /World/House/Roof)

Properties: - Attributes - Typed data values (position, color, opacity) - Relationships - Links between prims (material binding) - Properties can be time-sampled for animation

Metadata: - Key-value data attached to prims, properties, or layers - kind, purpose, hidden, active - Custom metadata for pipeline information

File Formats¶

Schema Types¶

Typed Schemas (IsA): - Define prim types with built-in properties - UsdGeomMesh, UsdGeomXform, UsdLuxDistantLight - Prim can only have one typed schema

API Schemas (HasA): - Add capabilities to prims - Can stack multiple API schemas on one prim - UsdShadeMaterialBindingAPI, UsdGeomModelAPI - Applied vs Non-Applied API schemas

📖 OpenUSD Schema Documentation - Schema reference

Domain 2: Scene Composition¶

Composition Arcs¶

LIVRPS (Composition Order - strongest to weakest): 1. Local opinions - Direct edits on the layer 2. Inherits - Inherit from another prim (class-like) 3. VariantSets - Switchable variations 4. References - Include external USD files or prims 5. Payloads - Deferred references (lazy loading) 6. Specializes - Like inherits but weakest (base class)

References¶

# USD Python API
prim.GetReferences().AddReference('./asset.usd', '/Root')

Payloads¶

prim.GetPayloads().AddPayload('./heavy_asset.usd')

VariantSets¶

vset = prim.GetVariantSets().AddVariantSet('color')
vset.AddVariant('red')
vset.AddVariant('blue')
vset.SetVariantSelection('red')

Inherits¶

• Prim inherits properties from another prim (class)
• Changes to class propagate to all inheriting prims
• Stronger than references (overrides reference opinions)
• Used for shared defaults across many assets

Layer Stack¶

• Multiple layers compose to form the final scene
• Stronger layers override weaker layers
• Root layer is strongest
• Sub-layers add opinions in order
• Non-destructive editing through layer separation

📖 USD Composition - Composition reference

Domain 3: Omniverse Platform¶

Architecture¶

Nucleus: - Central collaboration server - Stores USD files and assets - Real-time synchronization - Version control for scene files - Access control and permissions - 📖 Nucleus Documentation

Connectors: - Plugins for DCC tools (Maya, Blender, 3ds Max, etc.) - Live sync between DCC and Omniverse - USD import/export - Material translation

Kit SDK: - Framework for building Omniverse applications - Extension-based architecture - Python and C++ APIs - UI framework (omni.ui) - Viewport and rendering integration - 📖 Kit Documentation

Key Applications¶

• USD Composer - Scene layout and composition
• USD Presenter - Interactive visualization
• Audio2Face - AI-driven facial animation
• Machinima - Real-time storytelling
• Code - Development environment

Domain 4: Rendering and Materials¶

USD Preview Surface¶

• Standard material definition in USD
• Cross-platform compatibility
• Properties: diffuseColor, metallic, roughness, opacity
• Basic PBR (Physically Based Rendering) material

MDL Materials¶

• NVIDIA Material Definition Language
• Advanced physically-based materials
• Procedural textures and functions
• GPU-optimized rendering
• 📖 MDL Documentation - Material language

Hydra Render Delegates¶

• USD's rendering architecture
• Pluggable render backends
• Storm (OpenGL/Vulkan rasterizer)
• RTX (NVIDIA ray tracing)
• Third-party delegates (RenderMan, Arnold)

Lighting¶

• UsdLux light types: DistantLight, SphereLight, RectLight, DomeLight
• Light linking and shadow controls
• IBL (Image-Based Lighting) with DomeLight
• Physical light units

Domain 5: Collaboration¶

Multi-User Workflows¶

• Nucleus server enables real-time collaboration
• Live layers for per-user edits
• Layer locking for conflict prevention
• Merge workflows for combining changes
• Checkpoints for version snapshots

Asset Management¶

• Consistent naming conventions
• Asset resolution (ArResolver) for path mapping
• Reference counting for dependency tracking
• Payload management for scene optimization

Exam Tips¶

Key Concepts to Master¶

1. LIVRPS composition order (memorize this)
2. References vs Payloads (loading behavior)
3. USD file formats and when to use each
4. Prim types and schema system
5. Omniverse Nucleus and collaboration model
6. Hydra rendering architecture