What is the NWF file format?
.nwf is the live project work file format for Autodesk Navisworks, the BIM coordination and clash-detection platform used in architecture, engineering, and construction workflows. Originally developed by NavisWorks Ltd. around 1999-2000 under the JetStream product line, the format was carried over when Autodesk acquired the company in 2007.
An .nwf file does not embed geometry. Instead, it stores references (file paths) to external source models - DWG files, .nwc caches, or native CAD/BIM exports - together with all Navisworks session data: saved viewpoints, camera animations, redline markups, comments, clash detection settings and results, and TimeLiner construction sequence schedules. When the .nwf is opened, Navisworks loads the referenced geometry on the fly; updates to the source models appear automatically on the next open.
This reference-based architecture makes .nwf the recommended working format during active coordination. For distribution or archiving, teams publish to .nwd, which freezes the geometry into a self-contained snapshot. The third format in the family, .nwc, is a per-model geometry cache.
Navisworks Freedom - Autodesk's free viewer - cannot open .nwf files; it supports only .nwd and 3D DWF. Full .nwf access requires Navisworks Manage or Navisworks Simulate. If referenced source files are moved or renamed, the .nwf will open but fail to display geometry.
Security & safety
RISK: LOWNWF files are BIM/CAD project coordination data; no known malware risk. The main concern is confidentiality - NWF files embed the full project's coordination history, markups, clash results and construction schedule data. Share only with authorized project participants. Download Navisworks only from autodesk.com to avoid unofficial repackaged installers.
Format details
in a nutshellPrograms that open NWF files
Windows2 apps
Autodesk Navisworks Manage
Paid File > Open, select the .nwf. Navisworks will load the referenced source files from their stored paths to reconstruct the geometry alongside the markups/clash data.
Autodesk Navisworks Simulate
Paid Same as Manage - open the .nwf to access markups and viewpoints. Simulate lacks the full clash detection run capability but can open NWF and view existing results. Technical details
deep spec| Developer | Autodesk (orig. NavisWorks Ltd., acquired 2007) |
| Platform | Windows only |
| Byte order | Little-endian (Windows-native) |
| Internal compression | zlib (per Autodesk documentation) |
| Encoding | Binary (proprietary Autodesk Navisworks format) |
| Magic bytes | None publicly documented |
| MIME type | `application/octet-stream` (no registered type) |
| Geometry storage | None - references external source files (NWC caches, DWG, RVT, IFC, etc.) by path |
| Session data stored | Viewpoints, camera animations, redline markups, clash detection results, TimeLiner schedules |
| Typical file size | 10 KB - 50 MB (references and session data only, no embedded geometry) |
| Version compatibility | Newer Navisworks reads older NWF; Navisworks Freedom cannot open NWF at all |
| Related formats | `.nwd` (self-contained frozen snapshot), `.nwc` (per-model geometry cache) |
| Required software | Navisworks Manage or Navisworks Simulate (Freedom viewer cannot open NWF) |
| Released | circa 1999 (NavisWorks JetStream era); Autodesk acquisition 2007 |
| Latest version | Navisworks 2026 (current) |
| Specification | www.autodesk.com |
NWF conversions
Community Q&A
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