material-bind-scope#

Code

VM.BIND.001

Validator

latest+

Compatibility

open usd

Tags

✅

Summary#

Material bindings must use appropriate scope to ensure proper material assignment and inheritance.

Description#

Material bindings must be applied at the appropriate scope in the scene hierarchy. This ensures proper material assignment and inheritance throughout the scene.

When a material binding relationship is defined within a payload, it must target materials that exist within that payload’s scope. Bindings to materials outside the payload scope break encapsulation and can cause issues with composition.

Why is it required?#

  • Broken material references

  • Composition issues

  • Reduced asset portability

  • Unreliable material assignments

Examples#

# Invalid setup:
# Main file (asset.usda):
def Xform "World"
{
    def Xform "Scene" (
        payload = @./payload.usda@  # Loads payload with mesh
    )
    {
    }

    def Material "Material"  # Material defined outside payload
    {
        # ... material definition ...
    }
}

# Payload file (payload.usda):
def Xform "Root"
{
    def Mesh "Mesh" (
        apiSchemas = ["MaterialBindingAPI"]
    )
    {
        rel material:binding = </Material>  # Invalid: References material outside payload scope
    }
}

# Valid setup:
# Payload file (payload.usda) should include its own materials or reference materials within its scope:
def Xform "Root"
{
    def Material "Material"
    {
        # ... material definition ...
    }

    def Mesh "Mesh" (
        apiSchemas = ["MaterialBindingAPI"]
    )
    {
        rel material:binding = </Root/Material>  # Valid: References material within payload scope
    }
}

How to comply#

  • Move material definitions into the payload

  • Update material bindings to reference materials within the payload scope

  • Ensure material paths are relative to the payload root

For More Information#