If you work in the AEC or manufacturing sectors, you inevitably encounter a bewildering range of Autodesk file format extensions. DWG, DXF, RVT, RFA, IPT, IAM, DWF, NWD, IFC — each represents a different application, workflow, or stage in the design process. Understanding what each format contains, which applications create and consume it, and how they interact is fundamental to working efficiently in a multi-disciplinary design environment.
This guide covers the most important Autodesk file formats, explains their purpose and capabilities, and clarifies which software you need to open them. The relevant applications are available from GetRenewedTech: AutoCAD, Revit, Inventor, Maya, Civil 3D, and Fusion 360, all at £39.99 per year.
DWG — The Industry Standard 2D/3D CAD Format
Extension: .dwg
Created by: AutoCAD
Also used by: Civil 3D, Map 3D, AutoCAD Architecture, AutoCAD MEP, and dozens of third-party applications
DWG (Drawing) is the world’s most widely used CAD format, present in an estimated two billion files. It stores geometry (lines, arcs, polylines, 3D solids), text, dimensions, layers, blocks, and layout spaces. Despite being AutoCAD’s native format, it has become an open enough standard that virtually every CAD application either natively reads DWG or can import it.
DWG has evolved through multiple versions — AutoCAD 2000, 2004, 2007, 2010, 2013, 2018 — each incompatible with older applications that have not been updated to read the new version. When sharing DWG files with parties using older software, save down to an older DWG version via Save As > DWG format and selecting the appropriate version from the dropdown.
DXF — The Open Exchange Format
Extension: .dxf
Created by: AutoCAD
Used by: Virtually all CAD, GIS, and CNC applications
DXF (Drawing Exchange Format) was created specifically to allow interoperability between AutoCAD and other software. Unlike DWG, which is a binary proprietary format, DXF is a text-based (ASCII) format that can be read and generated by a very wide range of applications. It is the format of choice for sending geometry to CNC machines, laser cutters, vinyl cutters, and non-Autodesk CAD software.
The limitation of DXF compared to DWG is that it does not support all AutoCAD features — complex objects like 3D solids, certain block types, and external references may be simplified or lost during DXF export. Always verify the output after export, particularly for complex drawings.
RVT — Revit Project Files
Extension: .rvt
Created by: Autodesk Revit
Required to open: Autodesk Revit
RVT is Revit’s project file format, containing the complete Building Information Model: all geometry, parametric relationships, views, sheets, schedules, material assignments, and project data. RVT files are typically large — a complex building model may be 200MB or more — and they are version-specific. An RVT created in Revit 2024 cannot be opened in Revit 2023 without going through the upgrade wizard (which is a one-way process — you cannot easily downgrade afterwards).
This version specificity is an important practical consideration for project teams using different Revit versions. Establishing a common Revit version as part of your BIM Execution Plan at project start is essential.
RFA — Revit Family Files
Extension: .rfa
Created by: Autodesk Revit Family Editor
Revit families are the parametric component definitions used within Revit projects — doors, windows, furniture, structural sections, luminaires, and so on. RFA files are the loaded or loadable family files. They are shared across the industry and can be downloaded from manufacturer websites and BIM content portals. Load them into a project via Insert > Load Family.
IPT and IAM — Inventor Parts and Assemblies
Extensions: .ipt (part), .iam (assembly)
Created by: Autodesk Inventor
Required to open: Autodesk Inventor
IPT files contain individual Inventor part models — parametric solid bodies, sketches, and features. IAM files are assembly files that reference multiple IPT files (and other IAM files) and define how they fit together through constraints and joints. The distinction between parts and assemblies mirrors real-world manufacturing: you model individual components as IPT files and then assemble them in an IAM file.
Inventor assemblies can grow very large in terms of the number of referenced files. A best practice is to use project files (IPN) to manage file references so that all team members point to the same source files regardless of their local drive structure.
F3D — Fusion 360 Archive Format
Extension: .f3d
Created by: Autodesk Fusion 360
Fusion 360 files are primarily stored in Autodesk’s cloud (Autodesk Construction Cloud) and do not have a traditional local file extension in the way AutoCAD or Inventor files do. However, Fusion 360 designs can be exported as .f3d (Fusion archive) for offline backup, sharing with other Fusion users, or migration between accounts. Open them via File > Open > From My Computer in Fusion 360.
DWF and DWFX — Design Web Format
Extensions: .dwf, .dwfx
Created by: AutoCAD, Revit, and other Autodesk applications
DWF (Design Web Format) and its successor DWFX are lightweight viewing formats for sharing design data with parties who do not have CAD software. They are similar in concept to PDF for CAD — compact, non-editable, and viewable with the free Autodesk Design Review tool. DWFX uses the XPS document container and can be opened in modern Windows without any additional software.
NWD and NWF — Navisworks Formats
Extensions: .nwd (model), .nwf (file set), .nwc (cache)
Created by: Autodesk Navisworks
Navisworks is the Autodesk coordination and clash detection tool for BIM projects. NWD files are self-contained model aggregations containing all geometry from all contributing disciplines (architecture, structure, MEP) in a single file that can be viewed with the free Navisworks Freedom viewer. NWF files are lightweight container files that reference the original Revit, AutoCAD, and Civil 3D source files rather than embedding them.
IFC — The Open BIM Standard
Extension: .ifc
Created by: Revit, Civil 3D, ArchiCAD, Tekla, and most BIM applications
IFC (Industry Foundation Classes) is the open international standard for BIM data exchange, maintained by buildingSMART International. Unlike proprietary formats, IFC can be read by any IFC-compliant application, making it the format of choice for multi-disciplinary projects where different teams use different software. Revit exports IFC via File > Export > IFC; the output carries both geometry and semantic data (element types, material properties, relationships).
MA and MB — Maya Scene Files
Extensions: .ma (Maya ASCII), .mb (Maya Binary)
Created by: Autodesk Maya
Maya’s scene files use either ASCII (.ma) or binary (.mb) format. The ASCII format is human-readable and better for version control (changes are visible as text diffs), while the binary format is more compact and faster to load for large scenes. Both contain scene geometry, materials, lighting rigs, animation data, and render settings.
Choosing the Right Format for Each Task
- Sending drawings to contractors: DWG (specify version) or PDF
- Exchanging with non-Autodesk CAD users: DXF
- Sharing a BIM model across disciplines: IFC or NWD
- Revit family sharing: RFA
- Viewing without CAD software: DWF/DWFX or PDF
- Exporting from Inventor for manufacturing: STEP (.stp) or IGES (.igs) for neutral format; DWG or DXF for 2D drawings
Understanding these formats is foundational for anyone working across the Autodesk ecosystem. Whether you are an architect working between AutoCAD and Revit, an engineer using Inventor and Fusion 360, or a visualiser working in Maya, a clear understanding of which format to use for each exchange scenario will save time, prevent data loss, and ensure smooth collaboration across every project.
