cadmpeg-codec-catia

Decoder for Dassault Systèmes CATIA V5 .CATPart files.

What is implemented

A .CATPart is a V5_CFV2 container: an outer file header with a big-endian directory offset/length pair, and (for most parts) a nested V5_CFV2 sub-container whose CATIA_V5 CB0001 directory catalogues named logical streams as extent lists. The geometry is stored in one of five distinct families, each with its own decode path. This codec:

• [CatiaCodec::detect] recognizes the unique V5_CFV2\0 outer magic;
• [CatiaCodec::inspect] parses the outer header, reconstructs the inner stream directory, enumerates its named streams, and identifies the storage variant (spec §1) — this works for every variant;
• [CatiaCodec::decode] decodes standard-nested 05 08 01 vertex points, tag-bridged planes, and inline analytic carriers from SurfacicReps; it also decodes directly framed analytic carriers in zero-entity a9 03 streams, E5 circle/cone/torus carriers, and a8/a5 freeform NURBS carrier pools where present.

What is decoded, and what is reported as loss

Standard-nested geometry decodes vertices, analytic carriers, compatible circle/line carriers, and faces when their stored senses are available. Zero-entity, E5, and object-stream families transfer their directly framed carriers. Remaining carrier-to-topology bindings are reported as loss rather than fabricated.