Appearance and contact are separate questions
A surface can look like polished steel while using inappropriate contact properties for your task. Conversely, an asset can have a useful friction model without photorealistic textures. Review visual and physical requirements separately, then test them together in the final scene.
What a visual material describes
UsdPreviewSurface provides a shading model with inputs such as diffuse color, metallic, roughness and normal. These describe appearance under a renderer. They do not establish a measured friction coefficient or prove that a surface will behave like the real material during contact.
When inspecting a package, check texture resolution where the robot's camera will see the object, missing maps, UV seams and changes under representative lighting. A large texture file is not automatically useful if the object occupies only a few pixels in the task view.
What a physical material describes
The UsdPhysics material API describes contact-related parameters including friction and restitution. Inspect the assigned values, bindings and their source. The name of a material alone is not evidence that those properties were measured.
For sliding or grasping tasks, test the asset against the actual simulated counterpart surface. Keep runtime settings and initial conditions fixed while comparing material changes.
A package review checklist
- Open the scene from a different directory to find broken texture paths.
- Check the composed material assignment on the actual mesh or subset.
- Compare camera views under the lighting expected in the task.
- Confirm which physical properties are present and which use defaults.
- Keep measured values, approximations and visual variations distinguishable.
Changing the appearance of a scene should not silently change its physical behavior unless that is an intentional experiment. Similarly, physical randomization should be recorded independently from a cosmetic material variant.
Explore the material library and inspect each item's available maps and properties. See the domain randomization guide for a controlled approach to variations. A material thumbnail demonstrates appearance, not runtime validation.