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FIAT G91-R (Gina) - JSBSim

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Re: FIAT G91-R (Gina) - JSBSim

Postby erik » Mon Jun 06, 2016 11:17 am

It occurs to me that what might make a difference (and I think is appropriate for reflective surfaces) is to increase the contrast (or gamma?) for the ambient side. This happens because the reflective surface reflects directionally instead of spreading the reflection to all directions.

I'm not sure if this is easy to implement though.

Update: And then I realized that the essence of ambient light is that the source light comes from all directions which means that by definition all reflections are always in all directions too.

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Re: FIAT G91-R (Gina) - JSBSim

Postby Thorsten » Mon Jun 06, 2016 11:41 am

And then you realize that in nature this isn't quite true because the ambient light outside predominantly comes from the sky, you introduce an irradiance map to capture this, and for specular surfaces you see the sky reflected in shaded surface, turning this

Image

(omnidirectional ambient light)

into that

Image

(irradiance map and specular reflection of the bright sky)
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Re: FIAT G91-R (Gina) - JSBSim

Postby abassign » Mon Jun 06, 2016 12:00 pm

Thorsten wrote in Mon Jun 06, 2016 10:34 am:
Albert Einstein had his Nobel prize for the photoelectric effect, or for a theory that would explain why so physically correct a metal body (conductive) re-emits photon

He'd be a bit depressed reading this... The article you linked clearly says it:


I must admit that I made a serious mistake, which I talked about basic things that require an ability to link that not all minds have. Unfortunately the school, but often also the University, teach these things with an ancient physics just trying to justify the observations (eg the reflection of light to metals), but should not be at the origin of the problem.
The phenomenon by which a metal reflects light is based precisely on the fact that the electron absorbs a photon https://en.wikipedia.org/wiki/Photon , and then goes to a higher energy state, but this state can not keep it for too long and then, in an extremely short time, re-emits the photon before practically absorbed with the same energy and hence wavelength, if in the meantime has not interacted with something.
http://hyperphysics.phy-astr.gsu.edu/hbase/mod5.html#c1
Here is the importance of the photoelectric effect Albert is in having assumed the existence of a new particle called the photon that will be discovered only in 1926 and in having explained in an elegant way how can a metal reflect a photon, which is difficult to conceive for a particle that has no electric field and a mass almost nothing!

I could mention other interesting jobs (Feynman for example, who tries to understand the next point, which is how is the reflection from an electron energy decay due to re-emission) which explain the phenomenon of reflection, but almost all the current theories They are based on the photoelectric principle of our legendary Albert.
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Re: FIAT G91-R (Gina) - JSBSim

Postby erik » Mon Jun 06, 2016 12:04 pm

Thorsten wrote in Mon Jun 06, 2016 11:41 am:And then you realize that in nature this isn't quite true because the ambient light outside predominantly comes from the sky

Ah yes, nice comparison by the way.

Then, it might be a good idea to increase the contrast on highly reflective surfaces or does the irradiance map already have support for this?

Update: Ah I see there is a strength value which should do that:
http://wiki.flightgear.org/ALS_technica ... iance_maps

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Re: FIAT G91-R (Gina) - JSBSim

Postby Thorsten » Mon Jun 06, 2016 1:09 pm

@abassign: Maybe you should just /not/ talk about physics any more? There's things wrong aplenty in what you write.

* you don't need to invoke a photon to describe reflection, that works in fact fine in the classical picture
* you do however need photons for the photoelectric effect because that relies on the quantum nature of light
* you do however not need to understand photons to describe any phenomenon we can compute in real-time rendering
* it is neither true that a photon has no electromagnetic field (its nature is electromagnetic field) nor that it has no mass - cosmic ray photons can be significantly heavier than a proton
* Quantum Field Theory (which is these days used to compute the interactions of light with anything on the fundamental level) is in fact not based on Einstein's work - Einstein more or less despised its inherent randomness and preferred to try geometrical theories also for electrodynamics

which I talked about basic things that require an ability to link that not all minds have


Calling the quantum theory of light a 'basic thing' is otherwise known as 'intellectual terrorism' - it is not in any way basic, and the only reason to say so is to make others feel inferior. It is in fact a complicated problem requiring years of study to learn to compute, which you have evidently not mastered yourself.
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Re: FIAT G91-R (Gina) - JSBSim

Postby Thorsten » Mon Jun 06, 2016 2:52 pm

@Erik

Then, it might be a good idea to increase the contrast on highly reflective surfaces or does the irradiance map already have support for this?


I suspect on a highly reflective surface you want to use an environment cube map to fake some of the surrounding terrain reflections - at least that seems to be the standard technique in this case.

Otherwise... ALS should be pretty good in getting the details okay if you use model-combined-deferred.eff for your exterior. As you remarked, most of it is down to tweaking the relative balance of diffuse, ambient and specular surface properties. There's support for normal, reflection and environment cube map.

For the interior where we don't know the distribution of indirect light up-front, there's a selection of various models for both natural light coming through windows and artificial light from panel illumination. Again, for highly reflective surfaces, first thing I'd try is an environment cube.
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Re: FIAT G91-R (Gina) - JSBSim

Postby abassign » Mon Jun 06, 2016 3:28 pm

Thorsten wrote in Mon Jun 06, 2016 1:09 pm:@abassign: Maybe you should just /not/ talk about physics any more? There's things wrong aplenty in what you write.


:shock: ! :shock: ! :shock: ! :shock: ! :shock: !

I wish in this post you stopped to speak, at least for some time, it seems to me that your contribution is made only of resentment. I want to solve the problems not having new problems with you!
I would be deeply grateful if for once you do not put the last word and we end up here. Thank you with all my heart!
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Re: FIAT G91-R (Gina) - JSBSim

Postby Thorsten » Mon Jun 06, 2016 5:19 pm

I wish in this post you stopped to speak, at least for some time, it seems to me that your contribution is made only of resentment.


Okay, look: My interest is to see correct solutions and explanations presented in this forum. If you recommend to use an emissive animation to change the lighting on shaded surfaces, I think that is wrong and so you see me post to correct it.

If you invoke Einstein and the photoelectric effect to justify your initial mistake, that is also wrong and so you see me post to correct it.

If you then feel compelled to lecture me about how Quantum Electrodynamics works and get it wrong... you see me post to correct it.

If you want to see me stop answering here, just stop posting wrong advice and explanations - that's all it takes. There's no resentment of any kind involved, just a wish to see things straightened out.

Really.
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Re: FIAT G91-R (Gina) - JSBSim

Postby Johan G » Mon Jun 06, 2016 9:15 pm

@abassign There is probably little point in trying to correct Thorsten on physics (in particular particle physics) as he most probably has a better grasp on it than the rest of us. If I try a Google search with his full name and "jet" I find the results to be way above my head, though not in any way related aircraft. He is a doctor, but not a physician. ;)
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Fiat G.91 R4 v.10109 - JSBSim

Postby cobe571 » Tue Jun 07, 2016 1:50 am

Greetings to all,
months ago we stopped our work on this model. Actually called: Fiat G.91 R4 v.10109 - By the last R4 version number series produced after years. That pause was conditioned by a problem with our personal perspective we had on the licenses used by our project. All the licensing speech is born by me, probably. Your discussions has clarified your respective points of view that I greatly respect. Mine is that: For my 3D model and some FDM parts made by me, I use this License: Creative Commons, CC-BY-NC-ND 4.0 - If my plane is not within the canons of purity of GPL License - Patience. That's not my problem anymore. From my point of view, the use of mixed licenses for aircrafts like mine, will give the way to many great 3D artists, to be able to enter the world of simulation without the fear/anxiety of seeing their model sold by another person for another simulator. I would call it as a "protection" of the artist's work, rather than the programmer/coder job. Everyone couldn't be the best artist, or so skilled programmer like many of you on this Forum. This is a starting point for us - totally beginners; for our commitment that we spend into our Fiat G-91 R4. An italian airplane, made this time, by italian makers like us, more interested on the quality of our job. Me and abasign we cleared up between us months ago. Saying plain and simple we'll continue to do our work as we please and as we like to do. We'll always continue to use Flightgear for our personal purposes and airplanes case study, because it is a really beautiful and powerful simulator. Anyway other discussions about licenses we use and digressions that will go off topic the development of the aircraft will be considered absolutely not relevant and absolutely no longer acceptable. By this time I'd like to speak only about our plane. I'm sure you will understand perfectly! It's time to restart with some history about our plane:

The Fiat G.91, was a single-engine jet fighter-reconnaissance arrow wing designed by Eng. Giuseppe Gabrielli and produced by the Italian company Fiat Aviation. The G.91 is a low-wing monoplane, with arrow configuration with a 37 ° angle; the fuselage, with a half-shell made of light alloy, supports the engine in the rear trunk, immediately in front of which are arranged the fuel tanks and housings of the landing gear. In the forward section of the passenger compartment is arranged, under which is positioned the dynamic air intake for the engine; the pilot station was equipped with an ejection seat Martin Baker Mk.3 that it was later brought to the configuration 0 and 0 share speed, thanks to a pack of inferiorly arranged rockets which led him to a share such as to be able to open the parachute and let back ground the pilot without damage with the aircraft stationary on the ground. Machine guns (or, depending on the version, the cannons) are arranged next to the air intake under the cab and at the bow are mounted cameras and the same control equipment. The tail planes over the empennage are also compounds from a ventral fin of reduced size. Cart is front type tricycle: the front leg, in withdrawing backward, rotates 90 ° and the wheel is fitted flat below the air intake; the rear legs are space in the wing panels, with the wheels, retracting inwardly, are housed in the fuselage. Depending on the version, the wing panels are hooked two or four pylons which you can apply to fuel tanks or war loads (typically unguided bombs or rocket launcher). Throughout its lifetime the G.91 was powered by the Bristol Siddeley Orpheus turbojet (the same engine that powered the Folland Gnat). The prototype was equipped with a turbojet engine derived from that used for a surface-to-surface missile. For this reason it had a life span of only 300 hours (TBO) at the end of which was to undergo a general overhaul. With an excellent weight / thrust, it had a complex of parts comprising fuel adjustment system variously located on the engine. Characteristic the starter system that occurred at the hands of a small turbine driven by exhaust gases from the combustion of a charge of cordite.

Dimensions and weights

Length 10,29 m

Wingspan 8.56 m

Height 4.00 m

wing area 16,43 m²

curb weight 3100 kg

Maximum take-off weight 5500 kg

Propulsion

Bristol Siddeley Orpheus turbojet engine 803-02

Thrust 22.26 kN

Performance

max speed 0.78 Ma (1075 km / h at high altitude)

Autonomy 1150 km

Tangency 13 260 m

Armament

4 machine guns Browning M2 12.7 mm

Bombs free fall: up to 2000 kg

Missiles rockets: 38 SNEB 68 mm

4 underwing pylons

More updates about the Fiat G.91 R4 v.10109 - JSBSim will come soon... Thank you!

Image
Last edited by cobe571 on Wed Jun 08, 2016 10:05 am, edited 1 time in total.
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Re: FIAT G91-R (Gina) - JSBSim

Postby Thorsten » Tue Jun 07, 2016 5:31 am

From my point of view, the use of mixed licenses for aircrafts like mine, will give the way to many great 3D artists, to be able to enter the world of simulation without the fear/anxiety of seeing their model sold by another person for another simulator.


Let me re-iterate that mixed licenses are legally problematic if you want to distribute the plane in a single download and you may end up losing legal control over your work due to that.

Also, trying to have different parts of the FDM licensed in different ways would seem highly problematic because to not trigger GPL you have to argue that they're completely independent entities.

I think if you have a work created from scratch, dual-licensing a hires version of the 3d work under CC-BY-NC-ND 3.0 and a lower res version under GPL would be a clean option avoiding all complications.

Saying plain and simple we'll continue to do our work as we please and as we like to do


Till someone takes your work and sells it as he likes to do, and you discover you have no legal means left because of the way you arranged your licensing. We're not trying to screw you over, we're trying to help you find a safe option here.

Anyway other discussions about licenses we use and digressions that will go off topic the development of the aircraft will be considered absolutely not relevant and absolutely no longer acceptable.


I'm sorry, but to the degree that you (plural) make statements here that for example the renderer I maintain gets the lighting wrong and recommend to use the emissive channel to correct that, you will have to accept my reaction to that.

That is because all later problems - both with users of your plane and with aircraft maintainers adopting your techniques - will end up being reported to me as problems with my framework.

You don't own this thread - to the degree that digressions are relevant for the topic and moderation judges them so, you need to accept them.
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Fiat G.91 R4 v.10109 - JSBsim

Postby cobe571 » Tue Jun 07, 2016 8:02 am

@Thorsten. I'm not interested on your opinion. I've already contacted a lawyer for months, to get the information we need. So, your contribution does not add anything and even interest me. You want to produce your own projects under GPL, well, that's your right, so go ahead. This does not obligate us to follow your example and your suggestions even more unuseful to make a step forward. Our work will continue in the way that pleases and like us. If that bothers you, the problem is your .. Look elsewhere. If you don't like how we handle it, that's always your problems. And I repeat: Look elsewhere please! We will continue to do exactly our things in the way it seems good to us, not you. So, you can continue to pour out all the resentment you want. I don't care! We'll do as we please and we'll do it just because we are tired of reading words that have nothing constructive and add nothing to our efforts to complete this project. If by this time you'll stop from intervening on this thread, allowing us to work in peace without having to create each time a flame, to whatever is published, it will be a pleasure for everyone, cause right now you're becomin' pretty boring. At least for me. Anyway My 3D model is licensed and will stay under Creative Commons, CC-BY-NC-ND 4.0 https://creativecommons.org/licenses/by-nc-nd/4.0/ Our Fiat G.91 R4 v.10109 will continue the development on the path we choosed. That you like or not! That's all. Thank you!
Last edited by cobe571 on Wed Jun 08, 2016 10:07 am, edited 2 times in total.
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Fiat G.91 R4 v.10109 - JSBsim

Postby cobe571 » Tue Jun 07, 2016 8:14 am

I am proud to show you the really new Fiat G.91 R4 v.10109 landing gear...

Image
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Re: FIAT G91-R (Gina) - JSBSim

Postby Thorsten » Tue Jun 07, 2016 8:34 am

This does not obligate us to follow your example and your suggestions even more unuseful to make a step forward.


Kindly read what I wrote before answering to something I did not write.

Also, if you got a legal opinion, we'd all be interested in just exactly how it came out - there's plenty of complications and clearing up some of them may be helpful for everyone.

I'm not interested on your opinion.


That's fine - you're not obliged to read it, to consider it or to reply to it. But this is a publicly readable thread, not our private conversation, and others may be interested.

So, you can continue to pour out all the resentment you want.


Kindly stop your personal attacks.
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Re: FIAT G91-R (Gina) - JSBSim

Postby bugman » Tue Jun 07, 2016 8:48 am

@cobe571: I have just a few simple questions about the legal side, as abassign could not answer this. Are you taking Emmanuel Baranger's original GPL licensed aircraft as a starting point, and adding your awesome CC-BY-NC-ND 3.0 licensed model? Or someone else's GPL licensed content? Or are you creating everything new, and mixing the GPL and CC-BY-NC-ND 3.0 licence into one aircraft?

Note that no one is stopping you from developing a super detailed model. Even though I could not run it on my system, it is looking quite beautiful :)

Regards,
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