Module pmi 

PMI: dimensions, geometric tolerances, datums, their targets, and the drawing of them.

The machine-readable annotations AP242 calls semantic PMI: the values, not the leader lines. A dimension carries what it measures and its plus/minus bounds; a geometric tolerance carries its kind, magnitude and the datums it references; a datum is a letter on a feature, and its targets are the pads a fixture actually contacts it at. Everything anchors to topology nodes, the same way colours and names do, so an annotation survives every placement of the shape it describes.

And the presentation kind, which is the leader lines: where each annotation is drawn, in which plane, as which polylines. It is kept separate because it is separate: a drawing places its callouts where a draughtsman put them, and neither half derives from the other. What ties them is Callout::annotates, and a document may carry either alone.

Structs

Callout

One drawn annotation: the geometry a viewer puts on the screen.

Datum

A datum: a letter naming a feature other annotations reference.

DatumReference

One entry of a datum reference frame: a datum, or a common datum, and the modifiers that apply to it there.

DatumTarget

One datum target: which datum, which target of it, and where.

Dimension

A dimensional characteristic: a size or a location, with its values.

GeometricTolerance

A geometric tolerance: flatness, position, profile, and their kin.

Pmi

A document’s PMI, in file order: the semantic annotations, the targets a datum is actually contacted at, and the drawn presentation.

Enums

Annotated

Which semantic annotation a callout draws.

DatumModifier

A modifier on one datum reference of a frame.

DatumModifierKind

What a DatumModifier::WithValue sizes.

DatumTargetKind

Where a datum is actually contacted: the target a fixture touches it at.

MeasureKind

What a dimension’s value measures.

Constants

LEAST_MATERIAL

The modifier word for the least material condition, Ⓛ.

MAXIMUM_MATERIAL

The modifier word for the maximum material condition, Ⓜ: on a tolerance’s GeometricTolerance::modifiers or as a DatumModifier::Simple on a datum reference.