Crate cadmpeg_codec_nx 

Read Siemens NX .prt files into cadmpeg_ir::document::CadIr.

The codec recognizes the SPLMSSTR container signature, extracts compressed Parasolid neutral-binary streams from the canonical part payload, and decodes supported geometry and topology. Detection uses file content because NX and Creo share the .prt extension.

Support level: L4 for single-body, RMFastLoad-selected, and terminal-lineage-resolved body images; L2 for unresolved multi-partition history.

Decode a part

use std::fs::File;

use cadmpeg_codec_nx::NxCodec;
use cadmpeg_ir::{Codec, CodecEntry, DecodeOptions};

let mut input = File::open("part.prt")?;
let result = NxCodec.decode(&mut input, &DecodeOptions::default())?;

println!("{} bodies", result.ir.model.bodies.len());
for loss in &result.report.losses {
    println!("{:?}: {}", loss.severity, loss.message);
}

CodecEntry::inspect returns the SPLMSSTR directory and embedded-stream classifications without decoding entities. DecodeOptions::container_only produces metadata IR and skips entity decode.

Model and loss boundaries

NX stores part geometry in zlib-compressed Parasolid partition, deltas, or plain streams. The decoder converts Parasolid metre values to millimetres and emits points; analytic curves and surfaces; NURBS curves and surfaces; selected trimmed curves; and resolvable body, region, shell, face, loop, coedge, edge, and vertex topology. Each inflated Parasolid stream is also retained as an unknown record.

Read cadmpeg_ir::report::DecodeReport before using the model as a complete representation. Deltas streams pair with the preceding equal-schema partition in validated UG_PART segment order and apply supported non-topology full records and exact-key tombstones using the last event for each key. Valid partition topology remains authoritative. Unmatched tombstone relations remain unresolved. Segment body aliases, primary-body writers, and Boolean tool operands select terminal partition images when the complete body lineage is unambiguous. Assembly files may contain only references to external child parts.

Ordered feature-operation records, body dependencies, Boolean operations, sketch record lanes, and numeric expressions transfer from the NX object model. Operation suppression remains unresolved instead of being asserted active. Embedded JT coordinates and triangle connectivity transfer as canonical tessellations. Complete design history, assembly occurrence placement, material and appearance assignment, class-specific entity attribute fields, and .prt writing are not supported. Part attributes transfer as document attributes. The public submodules expose the lower-level container, stream, geometry, NURBS, intersection, and topology decoders. The object-model extraction and attachment tier (record families, feature semantics, and IR writing) is crate-internal and reached only through the decode entry point. Applications that need a complete IR entry point should use NxCodec.

Modules

container

Parse the SPLMSSTR header and its HEADER and FOOTER directories.

decode

Build IR and diagnostics from an NX SPLMSSTR container.

deltas

Walk status-byte-framed Parasolid deltas topology records.

geometry

Decode point and analytic geometry records from Parasolid neutral-binary data.

intersection

Decode chart-backed Parasolid surface-intersection constructions.

nurbs

Decode NURBS curves and surfaces from Parasolid neutral-binary records.

om

Frame NX object-model entities using external boundary and identity arrays.

om_tokens

Literals used by the NX object-model decoder.

parasolid

Extract and classify compressed streams in an NX part payload.

topology

Parse supported fixed-record Parasolid topology.

Structs

NxCodec

Decoder and inspector for Siemens NX .prt files.