What is the AFS file format?
.afs is a legacy project file format used by STAAD Foundation Advanced, a structural engineering application developed by Bentley Systems for the analysis and design of building foundations. The file stores all data for a single foundation project - including foundation geometry (isolated footings, combined footings, pile caps, mat foundations, strip footings), material properties, soil parameters, load cases and combinations, reinforcement schedules, and computed design results.
The .afs format was the native project format for STAAD Foundation Advanced prior to version 7. Starting with v7, Bentley replaced it with the .sfa format. A built-in AFS Converter dialog in current versions of the software migrates legacy .afs projects to .sfa in a single step.
The internal structure is proprietary binary; Bentley has not published the file specification, and no third-party tools can open .afs files. The format runs exclusively on Windows.
Note: the .afs extension was also historically used by Adobe Type Manager (ATM) for font set files, but ATM was discontinued by Adobe in 2005 when macOS and Windows gained native PostScript font rendering. That use is now entirely obsolete.
Security & safety
RISK: LOWA STAAD Foundation Advanced .afs file is a passive binary project data file - it contains no executable code and cannot harm your system. The Adobe ATM .afs font set variant is equally benign. No safety concerns beyond standard file handling.
Format details
in a nutshell- Adobe Type Manager Font Set - Discontinued Adobe utility (EOL May 2005) that saved font set configurations as .afs files; no longer in use since Windows Vista/macOS X added native PostScript font support.
Programs that open AFS files
Windows1 app
STAAD Foundation Advanced
Paid Open the legacy .afs project via File > Open, or use the AFS Converter dialog (in v7+) to migrate it to the current .sfa format before working with it. Technical details
deep spec| Encoding | Binary (proprietary Bentley format; no published specification) |
| Byte order | Little-endian (Windows x86/x64) |
| Application domain | Structural foundation analysis and design (isolated, combined, pile cap, mat, strip footings) |
| Stored data | Foundation geometry, material and soil properties, load cases and combinations, reinforcement data, design results |
| Platform | Windows only |
| Typical file size | 10 KB - 10 MB (varies with project complexity and number of foundation elements) |
| Successor format | `.sfa` (STAAD Foundation Advanced v7+) |
| Migration path | AFS Converter dialog in STAAD Foundation Advanced v7+ converts `.afs` to `.sfa` in a single step |
| Status | Legacy - superseded by `.sfa` in STAAD Foundation Advanced v7 |
| Alternate historical use | Adobe Type Manager (ATM) font set files - ATM discontinued by Adobe in 2005 |
| Released | 2000s (STAAD.foundation early versions) |
| Latest version | Superseded by .sfa format in STAAD Foundation Advanced v7+ |
| Specification | docs.bentley.com |
AFS conversions
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