GDnTReference

GDnTReference stores the datum reference frame sequence associated with a feature control frame. It records the ordered set of primary, secondary, and tertiary datums, including any material condition modifiers for each. By parsing the reference separately, the API enables precise reconstruction of how the feature must be oriented and constrained during inspection or assembly. The object links back to the feature control frame and the geometric elements that realize each datum, delivering the context necessary for tolerance analysis. It also retains confidence scores and detection sources, making it easy to flag datums that may require manual verification. Use this model to drive fixture design, evaluate measurement strategies, or confirm that supplier documentation references the correct datums and order.

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class GDnTReference(BaseModel):
    """
    Represents a reference for a GD&T characteristic.
    """

    association: Optional[GDnTReferenceAssociation] = Field(
        None, description="Reference for associating elements in tolerance evaluation."
    )
    parameter: Optional[GDnTReferenceParameter] = Field(
        None,
        description="Parameter of the reference element (e.g., peak value, deviation span).",
    )