What is the CAD file format?
.cad files are associated with BobCAD-CAM, a computer-aided design and manufacturing software developed by BobCAD-CAM, Inc. .cad files store 2D and 3D part geometry, including wireframe drawings, curves, and solid bodies. The format is used in engineering design for drafting and machining preparation - though .cad stores geometry data only; CAM job data and machine configurations are not retained in this legacy format.
.cad was the default file format used by BobCAD-CAM up until version 21. Subsequent versions adopted the .bbcd format for saving projects, which additionally stores CAM job and stock data. Still, the older .cad format remained supported in newer BobCAD-CAM versions for backwards compatibility.
The .cad extension is also used by several unrelated programs - including CadStd, PRO Landscape, and AutoSketch - each writing an entirely different proprietary binary layout, so reliably opening a .cad file requires knowing which application created it.
BobCAD-CAM places emphasis on compatibility with other formats available on the market, including:
Security & safety
RISK: LOWA .cad part file is passive geometry data and does not execute code on opening. The practical cautions are identification and sourcing: because many programs write .cad, a file from an unknown source may simply be unreadable in your CAD tool (not malicious, just a different format). Get CAD software only from the vendor's official site (bobcad.com, cadstd.com, prolandscape.com) rather than 'free CAD viewer' portals, which are a common source of bundled adware/PUPs. When in doubt, ask the sender for a neutral DXF or STEP export.
Format details
in a nutshell- CadStd drawing - Low-cost 2D CAD program CadStd saves drawings as .cad in its own format.
- PRO Landscape design - Drafix PRO Landscape uses .cad for landscape design plans - unrelated to BobCAD.
- Autosketch / generic 2D CAD - Autodesk Autosketch and other lightweight 2D CAD tools also emit .cad files.
Programs that open CAD files
Windows4 apps
BobCAD-CAM
Paid File → Open the .cad in BobCAD-CAM. Current versions can open legacy .cad parts and resave them as .bbcd.
CadStd
Freemium If the file came from CadStd (not BobCAD), open it in CadStd Lite (free) / CadStd Pro.
PRO Landscape
Paid Open landscape-design .cad files in PRO Landscape (Drafix). Unrelated to BobCAD .cad.
AutoSketch / Autodesk
Paid Legacy Autosketch .cad files open in Autosketch; the product is largely retired - export to DXF for modern tools. Technical details
deep spec| Format type | Proprietary binary 2D/3D CAD part file |
| Developer | BobCAD-CAM, Inc. |
| Byte order | Little-endian |
| Data scope | Stores part geometry (wireframes, curves, solid bodies) only - CAM job data, stock definitions, and machine configurations are not included |
| Successor format | .bbcd, introduced in BobCAD-CAM v22, which adds CAM job and machine data storage |
| Operating system | Windows |
| MIME type | application/octet-stream |
| Compression | Uncompressed (no documented compression layer) |
| Encryption | Not encrypted |
| Typical file size | 50 KB - 20 MB, depending on 2D or 3D part complexity |
| Extension ambiguity | The .cad extension is also used by CadStd, PRO Landscape, and AutoSketch - each with its own incompatible binary layout; identification requires knowing the originating application |
| Magic bytes | No publicly documented constant signature; identity must be determined from the creating application |
| Import/export support | Compatible with DWG, STEP, IGES, SLDPRT, STL, SAT, X_T, X_B, 3DM, DSF via BobCAD-CAM's import/export translators |
| Released | BobCAD-CAM (DOS/Windows era); .cad used through version 21 |
| Latest version | Final .cad usage in BobCAD-CAM v21; replaced by .bbcd in version 22 |
| Specification | bobcad.com |
CAD conversions
Community Q&A
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