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We have an engineer who needs CAD software which can read and edit .dwg files (preferably that runs on Windows but I could probably argue for a *nix box if needed). Before buying a commercial license I'd like to see, what if any, freeware or opensource CAD software exists. I've read through this post but the software here all specifies a license for personal use only. Everything I have found up to this point is a .dwg viewer only, is licensed for non-commercial purposes, or is paid software (with the possible exception of FelixCAD which I'm still looking into).

There are some really cool CAD packages such as BRL-CAD or Archimedes but these don't have the capability to work with .dwg files. My question then is, am I right that there is no freeware (with a commercial license) or opensource CAD software which can work with .dwg files? Or am I wrong and there is just such a package out there?

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closed as off-topic by random Dec 30 '14 at 14:49

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New answer

DraftSight, free for individuals, reviewed here as :

DraftSight is a proprietary freeware 2D computer-aided design (CAD) software application. The product was developed by Dassault Systèmes and lets users create, edit and view DWG and AutoCAD DXF files.

DraftSight for Windows was released in February 2011 and was downloaded more than 1.8 million times as of December 2011.

Languages available include English, Simplified Chinese, Traditional Chinese, Czech, French, German, Italian, Spanish, Japanese, Korean, Polish, Brazilian Portuguese, Turkish and Russian.

Old answer (read comments first)

DoubleCAD XT

DoubleCAD XT™ is an AutoCAD LT work-alike. But free.


A9CAD is a general purpose two-dimensional CAD program. It supports industry standard DWG & DXF drawing formats.


HYCAD is a useful and general purpose CAD program, green and small but powerful.
HYCAD can export multiple format files, such as dwg dxf eps bmp jpg png etc. it is easy to learn and much like AutoCAD.

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These seem to be just what I'm looking for. Thank you harrymc. – Wagnarock Nov 11 '09 at 21:06
A9CAD's url is broken. The company website still works but is just a feed from a civil engineering news site. A9cad is still listed on a download page, however the release hasn't been updated since 2005. I wouldn't bother with it. HYCAD fares a little better, with it's latest release dated 2009. It doesn't have any dedicated web resources (home page, forums, etc.). DoubleCAD XT appears to be a more actively maintained product, listing Win7 and a release date in 2012. To get download link you need to withstand a barrage of marketing profile building questions. – matt wilkie Jun 25 '13 at 18:04
DoubleCAD direct download link is, but still requires a Serial # and Activation Code, which are provided "free", in exchange for the aforementioned marketing profile and voluntary submission to spam list. However all this may be moot as the download link gives me constant "The connection to the server was reset while the page was loading." – matt wilkie Jun 25 '13 at 18:20
@mattwilkie: This answer dates from 4 years ago and the world moves on. A newcomer is DraftSight, last release in 2013. – harrymc Jun 25 '13 at 18:24
Yes the world certainly does move on harrymc:) The point of my comments are to document some of that movement and give current searchers something to work with. Thanks for the DraftSight pointer. Maybe it should be edited into the answer at the top of the list (to indicate currency). – matt wilkie Jun 25 '13 at 18:31

The only thing I could find on sourceforge when searching on the keyword DWG that mentioned anything about writing DWG files was OpenDWG. However, OpenDWG has not posted any files.

On the bright side, there is some code in their SVN repository. The mention that you can check out their repository as follows:

svn co opendwg

Other than that, I agree with ldigas' answer in that DWG is a proprietary format.

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I don't think you'll so easily find an open source one, which handles .dwg. For starters, .dwg is not open source (there have been some initiatives to make part of it public, but it never lived on fully).

As far as CAD goes on *nix boxes, in general, it was never spread as on Win ones, starting from software, up to drivers for specific used graphic cards, and so on ...

However, what you could do, if you're interested in writing a interface to a already existing format, is check out openNURBS. It is a Rhino community project (that has already taken some development), and if I understand correctly they provide an acess to Rhino's format (a NURBS modeling application, which is very respected in its own domains of application).

But this is just a sidenote.

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There is a product called Free DWG Viewer from Informative Graphics. - It is the product on the far right.

Was the question edited? I find it hard to believe that I completely misread the question.

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PROS - light and portable
CONTRAS - in Portuguese only and some ads

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