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Aircraft CC and GPL License and non-GPL FGAddon Question

Questions and discussion about creating aircraft. Flight dynamics, 3d models, cockpits, systems, animation, textures.

Re: Aircraft CC and GPL License and non-GPL FGAddon Question

Postby wkitty42 » Sat May 23, 2020 7:11 pm

Icecode GL wrote in Sat May 23, 2020 5:41 pm:Recurring discussions happen because people don't agree with each other.

it also happens because new folks come along and want to contribute but have questions and we're off to the races again ;)
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."
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Re: Aircraft CC and GPL License and non-GPL FGAddon Question

Postby bugman » Sat May 23, 2020 7:53 pm

@Hooray: Supermodels can also have pimples you know ;)

Seriously thought, the FSF mostly do a great job. Please consider donating (i.e. becoming a member):


You can also join without charge (you have to dig a bit to find it). That being said, I receive their mailing list messages and I have to say that I don't agree 100% with all their causes or opinions.

Regards,
Edward

Edit: Don't forget to donate at http://store.flightgear.org/ first ;)
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Re: Aircraft CC and GPL License and non-GPL FGAddon Question

Postby Alant » Sat May 23, 2020 10:15 pm

What about the sources of data used to make an aircraft simulation?
We have many aircraft that have clearly back-engineered manufacturer´s crew and systems (e.g. Garmin etc.) manuals to produce accurate models.
It is well understood that scenery designers should not own up to using Google Earth.
Where does the GPL stand on this?
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Re: Aircraft CC and GPL License and non-GPL FGAddon Question

Postby Thorsten » Sun May 24, 2020 5:54 am

It is well understood that scenery designers should not own up to using Google Earth.Where does the GPL stand on this?


My understanding is that GPL can't have a position on these because they're copyright and terms of use questions - GPL is only relevant once you have copyright and decided to license GPL.

The problem with Google Earth is not that Google would hold the copyright for the data (the layout of the Earth can't be anyone's intellectual property, facts can't be copyrighted), the problem is that the terms of use of Google Earth do not permit using it for e.g. measuring and accurately placing 3d models.

Similarly, the visuals of an aircraft are facts that can't be copyrighted, the systems may or may not be trade secrets, classified,... it depends really on the particular case, I don't know each and every one. In the case of the Shuttle, I know that all NASA material on it (manual, wind tunnel data,...) is in public domain and hence freeely usable. In the case of the Extra 500 I know that the FG maintainer has explicit permission from the manufacturer. In the case of the Seneca-II AP, TorstenD has - as far as I remember - measured all the parameters and rates from the real thing - since these are facts, no terms of use of the manual apply.

So this really is not one question but (at least) one per aircraft...
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Re: Aircraft CC and GPL License and non-GPL FGAddon Question

Postby Thorsten » Sun May 24, 2020 5:59 am

The FSF opinion, which is likely to be biased ;), is only their opinion. It is not a definitive legal ruling under copyright law in country X.


Yes - so basically every FAQ and explanation people can dig up in the internet disagrees with what you say - but they don't count because they're not a definite legal ruling in country X. I suppose if we had a definite legal ruling in country X, you'd go on (correctly) claiming that this doesn't necessarily apply to country Y.

It's called 'worship of gaps' - since a point can't be 100% proven but only 99%, you bet your money on the 'gap', i.e. the 1%. It's possible to do of course, but usually not a good idea.
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Re: Aircraft CC and GPL License and non-GPL FGAddon Question

Postby bugman » Sun May 24, 2020 9:44 am

I am well aware of the god of gaps, being a biologist. I also know that prophets will exploit the uncertainty of the gaps to indoctrinate the masses to advance their beliefs. Which is why we should avoid uncertainty. We should be discussing the technical details of the gaps, not worshipped false idols based solely on beliefs. Wow, this theme can be pushed quite far :)

However this case is most definitely not a gap. Instead we have a situation where the Free Software Foundation make a claim about interpreted languages, specially mentioning Perl, and the creator of Perl being forced to respond saying that the claim is false. I've followed these discussions for decades and have to agree with Larry Wall.

Regards,
Edward
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Re: Aircraft CC and GPL License and non-GPL FGAddon Question

Postby Thorsten » Sun May 24, 2020 10:43 am

You're entitled to your interpretation of course - but I haven't seen anything tangible that I would consider being in support of it. As I said, I think it (remotely) possible that a judge somewhere can be persuaded to follow the reasoning by a clever lawyer. But that's not sufficient reason for me to actually give weight to it. Unless tangible evidence is about to come at some near future point, I guess we have to leave it here.
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Re: Aircraft CC and GPL License and non-GPL FGAddon Question

Postby erik » Sun May 24, 2020 11:39 am

As a start I have contacted Melchoir Franz since he has started developing 24 of the earliest and most used Aircraft specific Nasal libraries.

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Re: Aircraft CC and GPL License and non-GPL FGAddon Question

Postby bugman » Sun May 24, 2020 7:42 pm

Thorsten wrote in Sun May 24, 2020 10:43 am:I guess we have to leave it here.


I was hoping that we would have a better definition and get more to the bottom of this. For example with an simple copyright demonstration aircraft that consists of a simple 3D model (e.g. a square body and smaller square cockpit), some demo Nasal that makes a demo call to the core library and a call to the extension library, an inclusion of one of the shared 3D instruments, etc. I.e. one incredibly basic demonstration a "whole" aircraft including each unique usage of FGData. Such a resource could then be discussed in technical detail (something absent from most previous discussions), and maybe studied by copyright lawyers to get legal opinions.

Regards,
Edward
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Re: Aircraft CC and GPL License and non-GPL FGAddon Question

Postby Hooray » Sun May 24, 2020 7:54 pm

Please don't send support requests by PM, instead post your questions on the forum so that all users can contribute and benefit
Thanks & all the best,
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Re: Aircraft CC and GPL License and non-GPL FGAddon Question

Postby bugman » Sun May 24, 2020 8:13 pm

Those are far, far too complex! I was thinking of something < 1 kb. Showcase copyright examples, not simple real models.

Regards,
Edward
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Re: Aircraft CC and GPL License and non-GPL FGAddon Question

Postby Hooray » Sun May 24, 2020 8:25 pm

You can trivially pick an arbitrary 3D model from $FG_ROOT (think the 3D cursor) and load it as an aircraft by wrapping it via an -set.xml file - I'd suggest to call it the bu...gmaneer :lol:
Please don't send support requests by PM, instead post your questions on the forum so that all users can contribute and benefit
Thanks & all the best,
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Re: Aircraft CC and GPL License and non-GPL FGAddon Question

Postby erik » Fri Jun 05, 2020 9:19 am

After some delay (technical difficulties at his side) I've got a response from Melchior:
I hereby agree with the addition of an exception to the license of all my Nasal contributions that clarifies that their use is permitted for any (otherwise legal) use of the FlightGear application and framework.

That's one important hurdle taken.

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Re: Aircraft CC and GPL License and non-GPL FGAddon Question

Postby erik » Wed Jun 10, 2020 6:49 am

Thorsten wrote in Sat May 23, 2020 6:31 am:That leaves open the question of simply using the Nasal interpreter. Here I don't know for sure - it is possible that simply using the interpreter also triggers the license, if so, I at least would see that as unintended, as I see the Nasal interpreter as something that indeed provides an environment (I'm not arguing that there is no such thing as an environment, I'm just arguing that things can't be arbitrarily declared to be 'environment' - especially not things that can easily be moved from aircraft to FGData and back) - so I'm certainly open to an FG-side statement that using the Nasal interpreter to run non-GPL licensed aircraft-side Nasal is okay.



Here is Andy's point of view on the matter:
That was certainly my intent: the Nasal interpreter is GPL, the code it runs certainly need not be. And I'd view that being true of any library code too, though for circumstances like that separately licensing the library code via LGPL or some other more permissive license would probably be a more formally correct way of doing things. I'd be happy to sign off on that too.
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