Namespace#

Code	UO.010
Validator	`NamespaceChecker`
Compatibility	open-usd
Applies to	custom PCB contract attributes
Requirement level	MUST for PCB contract attributes; the `pcb:` spelling and typo checks are advisory
Tags	`organization`

Summary#

Author PCB contract metadata under pcba:, with colon-delimited scopes and lower-camelCase leaf names. Use ordinary custom USD attributes: no custom schema, schema fallback, or plugin is required. Other domains’ properties retain their own namespaces.

This page follows PCBA to USD Input Contract 1.0.2, sections 1, 11 and 14.

Description#

The contract recognizes nine scopes:

Scope	Purpose
`pcba:component:`	component identity, placement, and package data
`pcba:mesh:`	geometry role and material class
`pcba:pin:`	component terminal identity and properties
`pcba:board:`	board-root metadata and board sites, pads, barrels, and registries
`pcba:prov:`	deferral markers; the leaf is the missing field’s bare leaf name
`pcba:layer:`	optional descriptive layer metadata
`pcba:panel:`	panel-to-board relationships
`pcba:fixture:`	tooling dimensions and assembly process
`pcba:variance:`	optional manufacturer-supplied package tolerances

The shorter pcb: spelling is also read, with an advisory warning; author pcba:. Unknown PCB scopes are likely typos and produce warnings rather than hard failures. This does not prohibit standard USD properties or custom metadata belonging to other domains.

Manufacturing variance carrier#

Author pcba:variance:* on the component (package prototype) prim, alongside its package data, once for all placed instances. These fields describe all through-hole pins of that package type; they are not per-placement measurements and do not belong on the board root. In a mixed-terminal package they do not cover its SMT pins.

Attribute	Type	Meaning
`pcba:variance:thtPinTiltToleranceDeg`	`float`	maximum tilt from the hole axis
`pcba:variance:thtPinOffsetToleranceMm`	`float`	maximum lateral offset in the bore
`pcba:variance:thtPinExtrusionToleranceMm`	`float2`	absolute minimum and maximum protrusion past the solder-side face
`pcba:variance:thtPinCutEndProfileList`	`token[]`	permitted pin-end forms, such as `straightCut` and `roundedEdge`

All are optional. Author them only from measured process-preparation or BOM data; omit unavailable values without a provenance marker. Geometry always represents the nominal: a consumer can ignore variance and still render the nominal board.

Why is it required?#

Consistent scopes let consumers discover domain metadata without depending on prim names, while keeping component, board, fixture, and package facts distinct.

Examples#

def Xform "R12"
{
    custom string pcba:component:refdes = "R12"
    custom token pcba:component:type = "resistor"
    custom float pcba:component:nominalRotationDeg = 90.0
    custom string pcba:prov:markings = "not_yet_available"
}

How to comply#

Use the scope for the concept being authored and lower-camelCase leaf names. Keep deferral markers on the prim that would carry the real field. Put package variance on the component prototype and board provenance on the board root.

NamespaceChecker checks recognized prefixes on discovered components and role-bearing meshes. It does not validate all property types, leaf names, variance values, or the variance carrier. Those obligations need separate inspection. For advisory-report visibility, see the PCB-Assembly guide.