Crate cadmpeg_codec_step 

Reads and writes cadmpeg_ir::CadIr documents as ISO 10303-21 STEP Part 21 exchange structures for AP203, AP214, and AP242.

Support: L9 (ladder).

StepCodec emits the application protocol selected through cadmpeg_ir::codec::write::Encoder::plan. It writes product and representation context, connected exact shape, product occurrences, tessellation, presentation, and PMI when the target schema carries those domains.

Export workflow

Construct or decode a cadmpeg_ir::CadIr, configure StepCodec, and select a target from the codec’s encoder catalog. Planning validates the request and returns the bytes with the export report.

Review cadmpeg_ir::report::export::ExportReport::losses before retaining output. Opaque records, source attributes, unsupported procedural definitions, and target-schema incompatibilities are reported or rejected rather than silently discarded. Body and face colors become per-face STYLED_ITEM presentation; direct geometry and tessellation bindings retain their native presentation targets.

Coordinates are emitted unchanged under a millimetre length-unit context. Callers must convert non-millimetre geometry before export. Analytic curves and surfaces map to their corresponding STEP carriers. Rational and non-rational NURBS use the *_WITH_KNOTS entities.

Structs

StepCodec

STEP encoder with per-export header options.

StepWriteOptions

Metadata written to the STEP FILE_NAME header record.

Enums

StepSchema

STEP application-protocol targets supported by the Part 21 writer.