Thanks Jürgen,

I can see why DXF might be more flexible given more software can open/import 
it, as compared to DWG. I have even made this argument to my co-workers. 
However, we have to convert to and from DWG on a daily basis (to and from QGIS 
or ArcGIS). When we export to DXF we have the extra step of opening the DXF in 
a full version of AutoCAD and then saving it as a DWG so our project managers 
can send on to clients who forward it to engineers and planners that prefer 
working with AutoCAD. I have to admit that this extra time adds up.

I am fine with this extra step but our managers have used this minor extra step 
as a reason to recommend we continue to pay our annual ESRI licensing fees 
whereas I want to free up this money to support QGIS and its development. 

The format of DWG seems to change every 2 or 3 releases. For example, my 
AutoDesk AutoCAD 2016 saves as AutoCAD 2013 (*.dwg) format but I know the 
latest AutoCAD 2019 saves a new version level.

If you were able to use the libdxfrw to write DWG and there was a way to offer 
a choice to export as DWG or DXF than I think one could really argue that QGIS 
was a one stop shop for converting to and from CAD format.

Not sure if the limitations mentioned by Stefan (thanks for those) are 
problematic

Rob

-----Original Message-----
From: QGIS-Developer <[email protected]> On Behalf Of 
[email protected]
Sent: Wednesday, September 26, 2018 15:00
To: [email protected]
Subject: QGIS-Developer Digest, Vol 155, Issue 76

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Today's Topics:

   1. Re: Exporting from QGIS to CAD format - is it possible to
      offer DWG export (Jürgen E. Fischer)
   2. Re: Exporting from QGIS to CAD format - is it possible to
      offer DWG export (Stefan Steiger)
   3. Plugin [440] Visibility Analysis approval notification.
      ([email protected])
   4. Plugin [1544] CityJSON Loader approval    notification.
      ([email protected])


----------------------------------------------------------------------

Message: 1
Date: Wed, 26 Sep 2018 14:23:08 +0200
From: Jürgen E. Fischer <[email protected]>
To: [email protected]
Subject: Re: [QGIS-Developer] Exporting from QGIS to CAD format - is
        it possible to offer DWG export
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"

Hi Rob,

On Tue, 25. Sep 2018 at 13:49:50 -0400, [email protected] wrote:
> Is there a proprietary licensing reason that QGIS cannot export 
> directly to *.dwg file format rather than only to the dxf format?

We could probably also use libdxfrw, that we use for our import, to write DWG.

But contentwise DXF and DWG are alike - and there's more software that can read 
DXF than DWG.  Is using DXF not an option?  Do you require a certain version of 
DWG (the format changed quite a bit, although the content actually didn't that 
much).



Jürgen

-- 
Jürgen E. Fischer           norBIT GmbH             Tel. +49-4931-918175-31
Dipl.-Inf. (FH)             Rheinstraße 13          Fax. +49-4931-918175-50
Software Engineer           D-26506 Norden             http://www.norbit.de
QGIS release manager (PSC)  Germany                    IRC: jef on FreeNode
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------------------------------

Message: 2
Date: Wed, 26 Sep 2018 12:52:13 +0000
From: Stefan Steiger <[email protected]>
To: Jürgen E. Fischer <[email protected]>,
        "[email protected]" <[email protected]>
Subject: Re: [QGIS-Developer] Exporting from QGIS to CAD format - is
        it possible to offer DWG export
Message-ID:
        <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"

You could use the ODA File-Converter to convert dwg to dxf and vice-versa. 
https://www.opendesign.com/guestfiles/oda_file_converter 

It can also run as batch-process. 
Runs natively on Linux/Mac/Windows, 32&64 Bit.
It's Freeware, AFAIK. 
That way you can guarantee it will always be able to read and write the latest 
DWGs. 


You can also use the Teigha Online File Converter, which converts .dwg/.dxf 
files to PDF/BMP.
https://www.opendesign.com/teigha_online_converter 


You cannot currently have a free program that reads and writes DWG on its own. 
DWG is a proprietary file format, on purpose designed to be difficult to 
understand, and it's encrypted. 
To be able to flawlessly read and write DWGs, you need to reverse-engineer the 
AutoCAD file format, by reverse-engineering AutoCAD. 
This naturally takes a lot of time, which means there are no Free-Software DWG 
libraries that implement a sufficiently large subset of the AutoCAD file 
format. 
There are currently only two software applications that offer a reliable DWG 
interface. 
One is ODA Teigha for C++/Java/.NET. 
The other is Woutware CADlib.

The problem with ODA-Teigha ist hat it takes royalties for each and every 
application deployed with Teigha. 
Which would be deadly for a free software project. 

WoutWare is better in this respect, as it requires a one-time license of 
currently 1'208 USD/year per developer. 
Also, Teigha is a pain in the ass to use. 
The problem with WoutWare is, that you need a new license each time you need to 
download a new version of WoutWare because there was a new version of AutoCAD. 
Also, WoutWare is .NET and therefore currently only works on Windows. 
There is a preview release of WoutWare for .NET Core (which works on Linux, and 
presumably on OSX too). 
.NET Core can be self-containedly deployed (Windows, Linux, Mac) , so there are 
no dependencies on a certain version of the .NET-Framwork. 

Those are the two only (working) options when you deal with DWG. 



-----Ursprüngliche Nachricht-----
Von: QGIS-Developer [mailto:[email protected]] Im Auftrag 
von Jürgen E. Fischer
Gesendet: Mittwoch, 26. September 2018 14:23
An: [email protected]
Betreff: Re: [QGIS-Developer] Exporting from QGIS to CAD format - is it 
possible to offer DWG export

Hi Rob,

On Tue, 25. Sep 2018 at 13:49:50 -0400, [email protected] wrote:
> Is there a proprietary licensing reason that QGIS cannot export 
> directly to *.dwg file format rather than only to the dxf format?

We could probably also use libdxfrw, that we use for our import, to write DWG.

But contentwise DXF and DWG are alike - and there's more software that can read 
DXF than DWG.  
Is using DXF not an option?  
Do you require a certain version of DWG (the format changed quite a bit, 
although the content actually didn't that much).



Jürgen

-- 
Jürgen E. Fischer           norBIT GmbH             Tel. +49-4931-918175-31
Dipl.-Inf. (FH)             Rheinstraße 13          Fax. +49-4931-918175-50
Software Engineer           D-26506 Norden             http://www.norbit.de
QGIS release manager (PSC)  Germany                    IRC: jef on FreeNode


------------------------------

Message: 3
Date: Wed, 26 Sep 2018 14:59:06 -0000
From: [email protected]
To: [email protected], [email protected]
Subject: [QGIS-Developer] Plugin [440] Visibility Analysis approval
        notification.
Message-ID: <20180926145906.14499.27892@2c6504964296>
Content-Type: text/plain; charset="utf-8"


Plugin Visibility Analysis approval by pcav.
The plugin version "[440] Visibility Analysis 0.6.4 Experimental" is now 
approved
Link: http://plugins.qgis.org/plugins/ViewshedAnalysis/


------------------------------

Message: 4
Date: Wed, 26 Sep 2018 17:22:43 -0000
From: [email protected]
To: [email protected], [email protected]
Subject: [QGIS-Developer] Plugin [1544] CityJSON Loader approval
        notification.
Message-ID: <20180926172243.14497.39587@2c6504964296>
Content-Type: text/plain; charset="utf-8"


Plugin CityJSON Loader approval by pcav.
The plugin version "[1544] CityJSON Loader 0.1 Experimental" is now approved
Link: http://plugins.qgis.org/plugins/CityJSON-loader/


------------------------------

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