What is the CGR file format?
A .cgr file is a CATIA Graphic Representation - a lightweight, tessellated 3D visualization model produced by Dassault Systèmes' CATIA V5 CAD software. Instead of storing exact parametric geometry, feature history, or B-rep surface data, a .cgr holds only the triangulated polygon mesh of a part or assembly together with visual attributes such as colors and surface normals.
The primary purpose is fast visualization and design review. Loading full .catpart or .catproduct files for a large assembly is computationally expensive; replacing heavy components with their CGR equivalents lets engineers navigate assemblies of thousands of parts without recomputing full geometry. This makes .cgr files a staple of Digital Mock-Up (DMU) workflows in the aerospace and automotive industries.
The format is a proprietary Dassault binary. No public specification exists, and there is no fixed magic number; the string CGR often appears near the start of the file, but identification relies on the file extension and CATIA context. File sizes typically range from a few hundred kilobytes to tens of megabytes depending on mesh density and model complexity.
Tools beyond CATIA that can open .cgr files include SolidWorks, eDrawings Viewer, CAD Exchanger, and Glovius. For broader data exchange, Dassault's 3DXML and open formats such as STEP are better suited when exact geometry transfer is needed.
Security & safety
RISK: LOWA CGR is passive 3D mesh data with no scripting or macro capability, so opening one in a CATIA-compatible viewer is low risk. As with any complex binary parsed by CAD software, malformed files could in theory exploit a parser bug, so only open CGR files from trusted sources and keep the viewer updated. Beware fake "CGR opener/converter" download sites that bundle adware - prefer the official vendors (Dassault eDrawings, CAD Exchanger, Glovius).
Format details
in a nutshellPrograms that open CGR files
Windows5 apps
SolidWorks
Paid File > Open and choose CATIA Graphics (*.cgr) to import the tessellated model as graphics. 
eDrawings Viewer
Free Free Dassault viewer that opens many CAD/graphics formats for view, measure and markup. 
Linux1 app
Android1 app
Technical details
deep spec| Encoding | Binary (proprietary Dassault Systèmes format) |
| Compression | Vendor-specific internal packing; not user-controllable |
| Typical file size | 100 KB - 50 MB (depends on mesh density and model complexity) |
| MIME type | application/octet-stream |
| Magic bytes | None published; the string "CGR" often appears near the file start |
| Geometry type | Tessellated polygon (triangle) mesh - not B-rep or parametric |
| Visual attributes stored | Per-face and per-vertex colors, surface normals, optional metadata |
| Parametric data | Not stored - no feature tree, no exact surface equations |
| Associated CAD platform | CATIA V5 (V5-6R-series releases) |
| Operating systems | Windows; legacy Unix CATIA workstations |
| Primary use case | Digital Mock-Up (DMU) visualization and design review; not for manufacturing or editing |
| Released | Late 1990s, with CATIA V5 |
| Latest version | Tied to the CATIA V5 release that wrote it (V5R-series; CATIA V5-6Rxxxx) |
| Specification | www.3ds.com |
CGR conversions
Community Q&A
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