Hello,

I am engineering rainwater storage systems and water treatment systems.

Is it allowed to use the open source for commercial use.

Is there any support how to use the software.

I am daily using FEM but it will take some time of practise to learn it.

Open source doesn't means you cand do commercial use. Generally it means that you have to pay if you want more professional support. Check stuff like OpenFoam, for instance.

Dear Lutat,

What I understood from GPL is that you cannot sell the software you make using the GPL'd software (give the others the rights you have been given). But services carried out using the software are out of the scope.

Of course, some advertising about the software you made use of would be kind. I am puting myself in the position of the OSS authors, not that I have heard anything in this direction.

hth, br,

Hélio.

That is not correct. You can sell GPL'd software without any problem. Please read the license if you have doubts on it.

Dear Reis,

The section 5 of the GPL states that (my highlights):

"""CITATION

5. Conveying Modified Source Versions.

You may convey a work based on the Program, or the modifications to

produce it from the Program, in the form of source code under the

terms of section 4, provided that you also meet all of these conditions:

a) The work must carry prominent notices stating that you modified

it, and giving a relevant date.

b) ***The work must carry prominent notices stating that it is

released under this License and any conditions added under section

7***. This requirement modifies the requirement in section 4 to

"keep intact all notices".

c) ***You must license the entire work, as a whole, under this

License to anyone who comes into possession of a copy. This

License will therefore apply, along with any applicable section 7

additional terms, to the whole of the work, and all its parts,

regardless of how they are packaged. This License gives no

permission to license the work in any other way, but it does not

invalidate such permission if you have separately received it.***

d) If the work has interactive user interfaces, each must display

Appropriate Legal Notices; however, if the Program has interactive

interfaces that do not display Appropriate Legal Notices, your

work need not make them do so.

A compilation of a covered work with other separate and independent

works, which are not by their nature extensions of the covered work,

and which are not combined with it such as to form a larger program,

in or on a volume of a storage or distribution medium, is called an

"aggregate" if the compilation and its resulting copyright are not

used to limit the access or legal rights of the compilation's users

beyond what the individual works permit. Inclusion of a covered work

in an aggregate does not cause this License to apply to the other

parts of the aggregate.

/CITATION"""

What I understand is that, yes, you can charge another user for the software, but he/she is free to pass it forward as soon as he/she have a copy. And you must forward the source code as well.

This is, of course, one of the main points the critics of OSS points like being harmful to software development: the profitability is precluded.

Of course, there are LGPL and BSD and others less restrictive to the commercial aspect, but the point in the root post was *services* using GPL software, which are allowed without restrictions.

I hope I have made the point more clear now, have I?

Best regards,

Hélio

Yes you are. Because what you say now is different from your first post, namely

"What I understood from GPL is that you cannot sell the software you make using the GPL'd software (give the others the rights you have been given)."

And now you are saying something like: You can sell the software BUT generally it doesn't make sense doing so.

Selling is NOT forbidden by the license, selling, with GPLd code, usually makes no commercial sense. It can seem a small detail but, it is still an important detail.

For instance, I can sell you pre-compiled, optimized binaries for your platform, something you might find difficult to do yourself, or just decide it doesn't worth the time spent tuning all the flags. But usually and mostly, indeed, profitability in opensource software is found in the services area.

best regards,

PS: I might add that selling tuned binaries is one of the commercial areas of a CFD company of a friend of mine.

I use OpenFoam + GroovyBC for pore-scale flow and reactive transport simulations and for solution of the closure problem. I can share details if you need it.