What is the CDW file format?
.cdw is a CAD document file created by KOMPAS-3D, a 2D/3D CAD suite developed by ASCON. A .cdw file stores a 2D technical drawing - vector geometry (lines, arcs, splines), layers, dimensions, annotations, and a title block. For 3D content, KOMPAS uses separate formats such as .m3d (part) and .a3d (assembly).
.cdw files are used for creating project documentation, design plans, and technical drawings, and can be exported to .dwg, .dxf, or PDF for use in other CAD applications or for production.
Internally, .cdw uses a Microsoft OLE2 Compound File Binary (CFBF) container - the same container as legacy .doc files - with proprietary KOMPAS streams holding the geometry and metadata.
.cdwis a proprietary CAD file format used by default in KOMPAS; the free KOMPAS-3D Viewer opens and prints.cdwfiles without a paid license.- Related KOMPAS document extensions:
.frw(2D fragment),.spw(specification/BOM),.kdw(text document),.m3d(3D part), and.a3d(3D assembly).
Security & safety
RISK: LOWA .cdw is a passive CAD drawing document - vector geometry and metadata, not executable code - so a genuine file is safe to open in the KOMPAS Viewer. Two minor cautions: it's stored in an OLE2 compound-file container (the same wrapper as legacy Office docs), and like any such file it should come from a trusted source; and "free .cdw converter / viewer" download sites can bundle adware, so get the KOMPAS-3D Viewer only from ASCON's official site (ascon.net / kompas.ru). For drawings from known colleagues or suppliers there is essentially no risk.
Format details
in a nutshellFULL NAMEKOMPAS-3D Drawingaka KOMPAS drawing file, ASCON KOMPAS 2D drawing
DEVELOPERASCON (АСКОН)since 1989 (KOMPAS); the .cdw 2D drawing format dates from early KOMPAS releases
CATEGORYCAD Files
MIME TYPEapplication/octet-stream
TYPEProprietary binary 2D technical-drawing document created by KOMPAS-3D / KOMPAS-Graphic (binary)
MAGIC BYTES · FILE SIGNATURE
OFFSET
0001020304050607
HEX
D0CF11E0A1B11AE1
ASCII
········
KOMPAS .cdw documents are stored in a Microsoft OLE2 Compound File (CFBF) container, so they begin with the standard OLE2 magic D0 CF 11 E0 A1 B1 1A E1 - the same header as legacy .doc/.xls. The drawing geometry and metadata live in proprietary streams inside that container, readable only by KOMPAS. (Some newer KOMPAS documents may use an updated container, but classic .cdw is OLE2-based.)
Programs that open CDW files
Windows3 apps
KOMPAS-3D Viewer
Free Install the free official Viewer and open the .cdw to view, measure and print it. The simplest no-cost way to open a KOMPAS drawing; also opens .frw/.m3d/.a3d and can export.
KOMPAS-3D
Paid The full CAD system: open and edit the .cdw, and File > Save As / Export to DWG, DXF or PDF for use elsewhere. A free trial is available.
KOMPAS-3D Home
Paid Lower-cost home/hobbyist edition of KOMPAS-3D that also opens and edits .cdw drawings (Russian-market product). 
Linux1 app
KOMPAS-3D (Linux build)
Paid ASCON offers a Linux build of KOMPAS-3D used in some CIS enterprise environments; opens and edits .cdw. (No free standalone Linux Viewer - use the Windows Viewer under Wine or convert on Windows.) Technical details
deep spec| Container format | Microsoft OLE2 Compound File Binary (CFBF) - same 8-byte signature (D0 CF 11 E0 A1 B1 1A E1) as legacy .doc and .xls files |
| Encoding | Binary (proprietary KOMPAS streams inside OLE2 container) |
| Byte order | Little-endian |
| Magic bytes | D0 CF 11 E0 A1 B1 1A E1 at offset 0 (standard OLE2 / CFBF signature) |
| MIME type | application/octet-stream (no registered MIME type specific to .cdw) |
| Drawing content | 2D vector geometry: lines, arcs, splines, hatches, dimensions, annotations, layers, and title block |
| Compression | Internal stream-level compression; geometry stored as vector primitives, not raster pixels |
| Password protection | Optional document-level password protection available in KOMPAS; not applied by default |
| Format versioning | Tied to the KOMPAS version that wrote it; newer KOMPAS opens older .cdw files, but older KOMPAS may not open files from a newer release |
| Typical file size | Tens of KB to several MB depending on drawing complexity and number of embedded views |
| Primary platform | Windows (primary target); KOMPAS-3D Linux build also supports .cdw |
| Sibling KOMPAS extensions | .frw (2D fragment), .spw (specification/BOM), .kdw (text document), .m3d (3D part), .a3d (3D assembly) |
| Export targets | DWG, DXF, PDF, and other formats via KOMPAS built-in export tools |
| Free viewer | KOMPAS-3D Viewer opens and prints .cdw files without a paid KOMPAS-3D license |
| Primary user base | Russian and CIS engineering, manufacturing, and construction industries |
| Released | 1989 (KOMPAS); the .cdw 2D drawing format dates from early KOMPAS releases |
| Latest version | KOMPAS-3D v23 (current as of 2026); .cdw format evolves with each KOMPAS release |
| Specification | ascon.net |
CDW conversions
Possible
.CDW .DWGGUIDE
Yes, CDW can be converted to DWG - open the file in KOMPAS-3D and use File > Save As (or Export) to write a…
How to convert
.CDW .DXFGUIDE
Yes - open the CDW in KOMPAS-3D (or the free KOMPAS-3D Viewer) and export directly to DXF.
How to convert
.CDW .PDFGUIDE
Yes, CDW can be converted to PDF - the fastest way is to open it in the free KOMPAS-3D Viewer and export or…
How to convert
.CDW .PNGGUIDE
Yes, CDW converts to PNG -- open the file in KOMPAS-3D or the free KOMPAS-3D Viewer and export the drawing as…
How to convert
Not possible
Community Q&A
asked by usersNo questions yet - be the first to ask about CDW files.
Frequently asked questions
How do I open a CDW file?
Use the free official KOMPAS-3D Viewer from ASCON (Windows) to view, measure and print it. To edit it you need the full KOMPAS-3D. Other CAD programs like AutoCAD can't open a .cdw directly - you must convert it first.
How do I open a CDW file without KOMPAS?
There's no reliable third-party viewer - the format is proprietary. The practical options are the free KOMPAS-3D Viewer, or asking the sender to export the drawing to DWG, DXF or PDF, which open in standard CAD/PDF software.
How do I convert a CDW to DWG or DXF?
Open the .cdw in KOMPAS-3D and Save As / Export to DWG or DXF (KOMPAS supports both). Then it opens in AutoCAD and most CAD tools. There's no dependable standalone converter because reading .cdw requires KOMPAS.
Can I convert a CDW to PDF?
Yes - open it in KOMPAS-3D or the free KOMPAS-3D Viewer and export/print to PDF. That's the easiest way to share or print the drawing for someone without CAD software.
What program creates CDW files?
KOMPAS-3D (and its 2D module KOMPAS-Graphic), the CAD system from the Russian developer ASCON. .cdw is its native 2D drawing document; related extensions are .frw (2D fragment), .m3d (3D part) and .a3d (3D assembly).
Can AutoCAD open a CDW file?
Not directly - AutoCAD doesn't read KOMPAS's proprietary .cdw. Open the file in KOMPAS-3D and export it to DWG or DXF first; AutoCAD opens those natively.
References
1ASCON - KOMPAS-3D product pageascon.net
2ASCON - KOMPAS-3D Viewer (free)ascon.net
