What is the CATPRODUCT file format?
.catproduct is a proprietary binary file used by Dassault Systèmes CATIA V5 to describe a mechanical assembly structure. Unlike solid geometry files, a .catproduct contains no geometry - it is a product structure descriptor that references .catpart files for individual part geometry and nested .catproduct files for sub-assemblies, recording positional constraints and hierarchical relationships between components.
The file uses the CGM (CATIA Geometric Modeler) proprietary binary format with big-endian byte ordering. Its internal structure encodes the assembly tree with component positions, mating constraints, and part instance references identified by file path or UUID. Moving a .catproduct without its entire referenced tree of .catpart and sub-assembly files will break all links.
A significant interoperability challenge is version locking: CATIA V5 embeds an R-release identifier (e.g., R21, R2023) in the file header, and earlier releases generally cannot open files saved by a newer release without a downgrade conversion step. Cross-system exchange typically requires exporting to neutral formats such as .stp (STEP) or .igs (IGES).
CATIA V5 remains dominant in aerospace, automotive, and defense industries. Dassault Systèmes' newer 3DEXPERIENCE platform uses .3dxml and .3drep formats, but the V5 installed base ensures .catproduct files stay in active use.
Security & safety
RISK: LOWBinary CAD file; no macro execution risk. Only risk is supply chain espionage if proprietary design data is shared outside secure channels.
Format details
in a nutshellPrograms that open CATPRODUCT files
Windows4 apps
CAD Exchanger
Freemium Import CATProduct; visualize and convert to STEP/STL/OBJ. Desktop and cloud versions.
eDrawings (with CATIA V5 import add-on)
Freemium Requires CATIA V5 import license; open for viewing and lightweight markup. 
macOS1 app
Technical details
deep spec| Format type | Proprietary binary CAD assembly descriptor |
| Geometry storage | None - geometry resides entirely in referenced `.catpart` files |
| Kernel | CGM (CATIA Geometric Modeler) proprietary binary container |
| Byte order | Big-endian |
| Internal compression | Proprietary (details not publicly documented) |
| Version stamp | CATIA V5 R-release identifier in file header (e.g., R19, R21, R2023) |
| Backward compatibility | Files from newer R-releases generally cannot open in earlier releases without downgrade scripts |
| Referenced file types | `.catpart` (component geometry), `.catproduct` (sub-assembly) |
| Typical file size | 10 KB - 50 MB (assembly descriptor small; total payload includes all referenced parts) |
| Operating systems | Windows, Linux (CATIA V5 server mode) |
| Neutral exchange formats | STEP (`.stp`), IGES (`.igs`), `.3dxml` |
| Primary industries | Aerospace (Airbus), automotive (BMW, PSA), defense |
| Released | 1998 (CATIA V5 initial release) |
| Latest version | CATIA V5-6 R2024 (ongoing; versioned as R-releases) |
| Specification | www.3ds.com |
CATPRODUCT conversions
Community Q&A
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