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Re: [libredwg] Spline object?

From: Jonathan Greig
Subject: Re: [libredwg] Spline object?
Date: Sun, 12 Dec 2010 23:32:07 -0600

I believe you meant to say: License incompatibility or personal disagreement with the GPL?

Part of the reason is that there are other projects out there that are CAD oriented that simply do the job already. Some have DWG support and others dont, but most support a CAD format that just works, be it .3DS, .DXF, .STL, .IGES, .VRML, 3d PDF(UD3 I believe), .SVG, .NC1(CAM related), etc...Several of these projects include OpenDWG(your biggest competitor besides AutoDesk itself), OpenCASCADE/SALOME, and OpenSceneGraph. QCAD3 is supposed to support DWG all the way up to version 2010 ( ). My guess is that it will use OpenDWG in some way and the GPL Community edition will certainly be stripped of DWG support, and the users will suffer. It's probably a programming nightmare to maintain both, so my guess is you've already been eliminated as a viable alternative at this point by the most common open source 'general CAD app' that the open source community would use. If Andrew follows this list, maybe he can comment on the situation.

I am a draftsman/detailer for a steel fabricator, and can say that most all CAD work is commercial. If somebody sends a format we cannot use in our CAD system, we simply email or call them and they send us the proper format. The format is not important, the data is. We use ProgeCAD at my workplace primarily for printing out DWG files, thats it other than some small projects that are artistic in nature and for those we always use DXF. AutoDesk opened the DXF format so CAD systems could exchange data reliably. In CAM systems, DWG is almost non-existant. Why? DWG is restricted and DXF is not. DXF version R12 is commonly used. Also, the need just isn't there when DXF and other formats already available. We commonly use DSTV(a type of .NC1 format) and only if thats not available, then use DXF(which we can always get). By restricting libreDWG to GPL, it will be an uphill battle the whole way. Considering if a user converts a DXF to DWG with libreDWG software, the data contained is still the users, that leaves only one really viable option for libreDWG: external data converters, something that most CAD users hate to do anyway and care little about. Since I am familiar with many CAD systems, I can tell you that having more 'users' involved in the project that use it everyday in a commercial environment will be beneficial, especially since some of the libreDWG programmers are great at the low-end programming but may not understand what the data represents or may have never used a high-end CAD system. Likewise, I understand the mathematics behind bezier/spline yet other CAD users may not. I've done a bit of low-end programming here and there and C/C++ is my primary language, but there are still alot of low-end specifics I don't even understand. Having more people involved that know what the end result should be is a good thing.

The other part of the reason is the licensing. I understand why the GPL is good in many ways, but it is too restrictive. The GPL is a deathwish to any proprietary project, just as releasing proprietary code without permission is a deathwish. The LGPL was made for projects such as this, because there are plenty of other software available that can do the same thing. Not to mention, as a programmer always having to double-check that you're GPL-compatible. If someone wants to make an open source app with closed source extensions or vice verse, then let them do so. Using a less restrictive license will effectively increase your userbase, as well as contributers to the project, improving stability much faster.

I've been developing a CAD app for awhile that I plan on it being open source in some way, but will also be commercial/proprietary for some parts of it. For this project, I have rejected all GPL libraries, unless they are dual-licensed with a commercial equivalent. I've also done work for various GPL projects, but the work always is useful to me regardless.

On Sat, Dec 11, 2010 at 11:32 AM, Rodrigo Rodrigues da Silva <address@hidden> wrote:
Hello Jonathan,

On 11/12/2010, Jonathan Greig <address@hidden> wrote:
> On a side note, I would like to be much more involved in this project, but
> it is not LGPL licensed.

What is the reason for that? License incompatibility or personal
disagreement with the LGPL? We have discussed in the past wether LGPL
would be a better license choice for the project.

Rodrigo Rodrigues da Silva
PoliGNU - Grupo de Estudos de Software Livre da Poli/USP
FSF Associate Member #7788

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