[QGIS-Developer] Exporting from QGIS to CAD format - is it possible to offer DWG export

rjwillson at gmail.com rjwillson at gmail.com
Wed Sep 26 14:35:47 PDT 2018


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-----
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Sent: Wednesday, September 26, 2018 15:00
To: qgis-developer at lists.osgeo.org
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.
      (noreply at qgis.org)
   4. Plugin [1544] CityJSON Loader approval	notification.
      (noreply at qgis.org)


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

Message: 1
Date: Wed, 26 Sep 2018 14:23:08 +0200
From: Jürgen E. Fischer <jef at norbit.de>
To: qgis-developer at lists.osgeo.org
Subject: Re: [QGIS-Developer] Exporting from QGIS to CAD format - is
	it possible to offer DWG export
Message-ID: <20180926122308.qdrv47rgw6dmtdll at norbit.de>
Content-Type: text/plain; charset="iso-8859-1"

Hi Rob,

On Tue, 25. Sep 2018 at 13:49:50 -0400, rjwillson at gmail.com 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 <Steiger at cor-management.ch>
To: Jürgen E. Fischer <jef at norbit.de>,
	"qgis-developer at lists.osgeo.org" <qgis-developer at lists.osgeo.org>
Subject: Re: [QGIS-Developer] Exporting from QGIS to CAD format - is
	it possible to offer DWG export
Message-ID:
	<454591AE08FDD64E8B82954659BC1BEA52300925 at COR-EXCHANGE.cor.local>
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:qgis-developer-bounces at lists.osgeo.org] Im Auftrag von Jürgen E. Fischer
Gesendet: Mittwoch, 26. September 2018 14:23
An: qgis-developer at lists.osgeo.org
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, rjwillson at gmail.com 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: noreply at qgis.org
To: cuckovic.zoran at gmail.com, qgis-developer at lists.osgeo.org
Subject: [QGIS-Developer] Plugin [440] Visibility Analysis approval
	notification.
Message-ID: <20180926145906.14499.27892 at 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: noreply at qgis.org
To: steliosvitalis at gmail.com, qgis-developer at lists.osgeo.org
Subject: [QGIS-Developer] Plugin [1544] CityJSON Loader approval
	notification.
Message-ID: <20180926172243.14497.39587 at 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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