yade-dev team mailing list archive

[Václav Šmilauer <eudoxos@xxxxxxxx>]

> The thing is I'd be glad to ask CGAL developers about CGAL license, 
> but I still don't know what to ask exactly.
> Could you point out the critical aspects that I need to check please?
Let me try. Yade itself can be apparently built with cgal, if we amend 
the license with exception clause for cgal (a
ll quotes from http://www.cgal.org/license.html):
> "It is therefore not possible to build a program including GPL code 
> and some QPL parts of CGAL. In this case, if you are the copyright 
> owner of the GPL code, you can amend the license by adding an 
> exception allowing the use of CGAL with it"
Now, the problem comes when someone modifies the program:
> "The Q Public License gives you the right to use the code under the 
> condition that any program using it be released itself under a 
> QPL-compatible Open Source license."
The first sentence is ambiguous and I see 2 possible interpretations:

1. The obligations pertains to the license choice: if you release (any) 
program that uses cgal, that program must be released under a license 
compatible with QPL.

2. The obligation pertains to the fact of releasing: if you have a 
program using cgal, you must RELEASE it (under license compatible with QPL).

It seems though that 1. is contradicted by the following phrase at the 
mentione page:
> "This also applies to programs that are not distributed (used only 
> internally)"
Suppose now a company uses internally a modified version of yade; then 
it follows they have to release their modified version. That is 
unacceptable.

You can ask them if the interpretation and implication is right.

> vtk doesn't have regular delaunay (triangulation of spheres - not 
> points). So, it can be usefull for something else perhaps but it would 
> not replace CGAL.
I am not familiar with vtk so much and to be honest I don't know what 
regular delaunay is ;-), but I will check it tomorrow.

I think there is a reason e.g. vtk is used so much compared to cgal 
(although their focus is quite different), and that's the license. 
Anyone should be reluctant to use something that excludes commercial 
use, since it is commercial funding AFAIK that drives non-negligible 
part of applied research. It also implies that the library is not 
packaged or is in special repositories, whereas more standard things can 
be found at any decent distribution -- this maintenance burden counts, 
for me at least, as well (recall wm3 and qglviewer).

Vaclav