What is the PIN file format?
A .pin file is a proprietary binary companion file generated automatically by ArchiCAD, the BIM (Building Information Modeling) application developed by Graphisoft (part of the Nemetschek Group). It serves as an internal index or metadata file associated with an ArchiCAD project, working alongside the main project file (.PLN).
Users do not open .pin files directly; ArchiCAD manages them transparently. They store index or tracking data about project components, linked library parts, or internal references - the exact content varies across ArchiCAD versions. The format is proprietary binary with no publicly documented specification, and files are versioned per ArchiCAD release.
In older ArchiCAD versions (pre-2000), .pin files were closely tied to the project index structure. Modern ArchiCAD (Archicad 25 and later) primarily relies on .pln for the main project, .gsm for library parts, and .bpn for backups, so .pin files from legacy projects may not function correctly in current versions without a format conversion step.
If a .pin file is missing or deleted, ArchiCAD typically rebuilds it automatically the next time the associated project is opened. The small file size (1 KB to 100 KB) reflects its role as a lightweight index rather than a primary data store.
Security & safety
RISK: LOWInternal CAD index file with no executable content; safe to handle.
Format details
in a nutshell- Generic PIN/pinout configuration file - Some electronics CAD and hardware tools use .pin for pin configuration or netlist data - unrelated to ArchiCAD.
Programs that open PIN files
Windows2 apps
Graphisoft File Converter
Free Use to convert old ArchiCAD project bundles (including PIN) to current Archicad format. 
macOS1 app
Technical details
deep spec| Format type | Proprietary binary project index/companion file |
| Encoding | Binary |
| Byte order | Little-endian |
| Compression | Unknown (no public specification) |
| Typical file size | 1 KB - 100 KB |
| Platform | Windows, macOS |
| Companion file | Paired with .pln (ArchiCAD main project file) |
| User interaction | Not user-opened; managed automatically by ArchiCAD |
| Version compatibility | Versioned per ArchiCAD release; older files may require conversion for newer versions |
| Developer | Graphisoft (Nemetschek Group) |
| Format specification | Not publicly documented |
| Status | Legacy; modern ArchiCAD uses .pln, .gsm, and .bpn as primary formats |
| Released | circa late 1990s (early ArchiCAD versions) |
PIN conversions
Community Q&A
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