| name | nonvisual-materials |
| description | Authoring non-visual material labels for sensor simulation. Use when user asks to assign lidar/radar/acoustic material semantics, choose nonvisual base materials, coatings, or attributes, debug material IDs, or bind sensor-facing USD materials.
|
| license | LicenseRef-NvidiaProprietary |
| version | 0.3.0 |
| author | NVIDIA ovrtx |
| tags | ["ovrtx","materials","sensors"] |
| tools | ["Read","Grep"] |
Nonvisual Materials
When to Use
Use this skill when the user asks to assign lidar/radar/acoustic material semantics, choose nonvisual base materials, coatings, or attributes, debug material IDs, or bind sensor-facing USD materials.
Inputs
Resolve inputs in this order: existing repository files and referenced snippets, explicit user request, then broader agent context.
- Target API surface: Python, C/C++, USD, or a combination.
- Sensor modality: lidar, radar, acoustic, or mixed sensor workflow.
- Material prim paths, desired base material, coating, attributes, prefix, and whether both supported prefixes must be authored.
- Geometry binding targets, existing visual materials, and any
MaterialId debugging or pointcloud attribution needs.
- Repository source snippets referenced below. Treat these snippets as the API source of truth.
Prerequisites
- Use an ovrtx checkout that contains the referenced examples and docs tests.
- Read the relevant
> **Source:** snippet before writing or explaining API usage.
- Author nonvisual labels on material prims; use
binding-materials when the geometry still needs material:binding.
- Use sensor configuration skills to request
MaterialId output channels, and interpreting skills to explain returned material IDs.
Instructions
- Identify the sensor modality, material prims, nonvisual base/coating/attribute labels, and prefix requirements.
- Read the matching USD source snippet before writing material metadata.
- Preserve exact supported base material, coating, attribute, and prefix strings.
- Keep visual material binding, nonvisual label authoring, and PointCloud
MaterialId reading as separate steps unless the user asks for the full workflow.
- When changing code, run the narrow docs test or example that owns the snippet whenever practical.
Output Format
- For explanations, cite the relevant API names, source snippets, and caveats.
- For code changes, summarize the files changed, snippets affected, and validation run.
Scripts
This skill has no scripts.
Limitations
- The referenced snippets remain the source of truth; update or add tested snippets before documenting new API usage.
Overview
Non-visual material labels let lidar, radar, and acoustic sensors map USD materials to sensor-return behavior. The visual MDL material can stay ordinary; the sensor semantics come from custom material attributes that encode a base material, coating, and optional attributes into a material ID.
USDA Pattern
Python example scene
Source: examples/python/sensors/radar/radar_example.usda snippet configure-nonvisual-materials
C example scene
Source: examples/c/sensors/radar/radar_example.usda snippet configure-nonvisual-materials
Author the labels on the Material prim that geometry binds with rel material:binding. The base material is required. Coating and attributes are optional; use none for unlabeled surfaces.
The default runtime prefix is omni:simready:nonvisual. The alternate supported prefix is inputs:nonvisual, selected by /rtx/materialDb/nonVisualMaterialSemantics/prefix. Public examples may write both prefixes so scenes work with either setting.
Base Materials
Use these exact base material strings.
| Category | Materials |
|---|
| Default | none (0) |
| Metals | aluminum (1), steel (2), oxidized_steel (3), iron (4), oxidized_iron (5), silver (6), brass (7), bronze (8), oxidized_Bronze_Patina (9), tin (10) |
| Polymers | plastic (11), fiberglass (12), carbon_fiber (13), vinyl (14), plexiglass (15), pvc (16), nylon (17), polyester (18) |
| Glass | clear_glass (19), frosted_glass (20), one_way_mirror (21), mirror (22), ceramic_glass (23) |
| Other | asphalt (24), concrete (25), leaf_grass (26), dead_leaf_grass (27), rubber (28), wood (29), bark (30), cardboard (31), paper (32), fabric (33), skin (34), fur_hair (35), leather (36), marble (37), brick (38), stone (39), gravel (40), dirt (41), mud (42), water (43), salt_water (44), snow (45), ice (46), calibration_lambertian (47) |
none and calibration_lambertian map to DefaultMaterial behavior. Other base materials default to CompositeMaterial behavior.
Coatings
| Coating | Index | Use |
|---|
none | 0 | Default, unlabeled, or unspecified coating. |
paint | 1 | Painted surface. |
clearcoat | 2 | Clear-coated surface. |
paint_clearcoat | 3 | Painted and clear-coated surface. |
TBD | 4-7 | Reserved for future use; do not select for authored content. |
Attributes
Attributes are encoded as a bit field, so multiple attributes can be combined when the USD representation supports a list.
| Attribute | Index | Use |
|---|
none | 0 | Unspecified attribute. |
emissive | 1 | Energy-emitting surface. |
retroreflective | 2 | Retroreflective surface. |
single_sided | 4 | Single-sided surface for non-thin geometry. |
visually_transparent | 8 | Material is visually transparent. |
TDB | 16 | Reserved for future use; do not select for authored content. |
Behavior Types
The material system can map material IDs to these BSDF behavior types: Constant, DefaultMaterial, CoreMaterial, AcousticMaterial, CompositeMaterial, RetroReflectiveMaterial, and ValidationMaterial.
Use behavior remapping settings only when a sensor model needs a non-default BSDF behavior for a material ID.
Troubleshooting
- Non-visual labels belong on the bound
Material, not directly on the mesh.
- Keep the runtime prefix and authored prefix aligned. If every object behaves like the same material, check
/rtx/materialDb/nonVisualMaterialSemantics/prefix.
- Preserve coating and attribute flags unless you intentionally want base-material-only behavior.
/app/sensors/nv/materials/preserveMaterialFlags=0xff keeps all flags.
paint and calibration_lambertian can use visual diffuse color information only when the sensor modality requests reflectance information.- Material remapping settings are per modality, such as
/app/sensors/nv/lidar/matNameToIdMapOverrides and /app/sensors/nv/radar/matBehaviorToIdOverrides.
Related Skills
binding-materials for USD material binding mechanics.configuring-lidar-sensors and configuring-radar-sensors for sensor output configuration.
References
- Use the
> **Source:** directives in this skill to locate tested snippets before reusing API patterns.
- Keep related skills, docs, and snippets synchronized when changing the workflow.
