Board index FlightGear Development

Sailing, anyone?

FlightGear is opensource, so you can be the developer. In the need for help on anything? We are here to help you.
Forum rules
Core development is discussed on the official FlightGear-Devel development mailing list.

Bugs can be reported in the bug tracker.

Re: Sailing, anyone?

Postby DFaber » Mon May 13, 2013 8:17 am

Cpt Goosnen wrote in Mon May 13, 2013 6:50 am:ok, when u or anybody else can give me a link for the null developement parameters i will take alook (searched alot but havent found any null dev description).


there is none, null FDM means there is nothing which cares for the Model, except for the Nasal code you write. I simply connect the AI system to the Model and control the Properties via the Nasal Script. If you like to help (which I appreciate a lot :-)) take a look at the Nasal documentation.

Thanks!
Detlef Faber
FlightGear Development:
http://flightgear-de.net

German FlightGear Forum
http://forum.flightgear-de.net
DFaber
 
Posts: 684
Joined: Fri Dec 01, 2006 7:51 pm
Location: Aachen, Germany
Version: GIT
OS: Linux

Re: Sailing, anyone?

Postby Hooray » Sat Jun 21, 2014 5:13 pm

This may be of interest to people interested in seeing vessels supported in FlightGear at some point: apparently there's some discussion on the BridgeCommand forum to possibly re-implement their simulator on top of FlightGear: http://www.bridgecommand.co.uk/forum/in ... ,38.0.html

I have an interesting idea! Use the same base as flightgear! or even suggest that the C++ implementation to be part of flight gear . For Flightgear have already some areas in the simulation scenarios that can be used for sea start and landing of air planes (in FG simulator to clarify) that have potons/hulls adapted for that. Basic hydrodynamic is already their (to some extent) and it has of curse aerodynamics simulation. Flight gear 3 whit some World scenery 2 uses Global water depth map


It would probably make sense to get in touch with them via their forum to see if they're serious about it - technically, it should be very feasible, we could even reuse/port their artwork (it being GPL already!), i.e. all the boats/vessels and textures.

Stuff like RADAR/ARPA, ECDIS or AIS could be easily implemented on top of Canvas/MapStructure, i.e. would be MUCH simpler than any existing code they may have:
Image
Image

"FDM" and weather (tides, currents) would be the main challenges in my opinion, which could probably still be worked around by using Nasal for starters.
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,
Hooray
Help write next month's newsletter !
pui2canvas | MapStructure | Canvas Development | Programming resources
Hooray
 
Posts: 11163
Joined: Tue Mar 25, 2008 8:40 am

Re: Sailing, anyone?

Postby Johan G » Sun Jun 22, 2014 1:25 pm

Maybe there could be a boat FDM "engine" of the same magnitude as JSBSim and YASim?

There has been FDM:s for boats and submarines done, so why not?

Question is though, how far away would FlightGear be from adding sea depth to the scenery not to mention tides and currents.


Somehow I feel that when FlightGear have been modularized and HLA adopted this could be a "simple" plugin/addon. :wink:

How is the HLA work going by the way. I guess work is going on even though there is little news. For once I do not mind sidestepping "release early and release often" here, as this has to be right and an architectural change like that has the potential to transform FlightGear into something more flexible and hopefully more maintainable. It would also most probably make it possible for FlightGear to work together with other simulations in many so far unforeseen ways.
Low-level flying — It's all fun and games till someone looses an engine. (Paraphrased from a YouTube video)
Improving the Dassault Mirage F1 (Wiki, Forum, GitLab. Work in slow progress)
Johan G
Moderator
 
Posts: 5292
Joined: Fri Aug 06, 2010 5:33 pm
Location: Sweden
Callsign: SE-JG
IRC name: Johan_G
Version: 3.0.0
OS: Windows 7, 32 bit

Re: Sailing, anyone?

Postby Algernon » Sun Jun 22, 2014 10:31 pm

OOOMG!
Please, please let this happen.
Algernon
FGUK - A FlightGear community in the United Kingdom and Republic of Ireland
User avatar
Algernon
 
Posts: 498
Joined: Sun Jun 27, 2010 3:55 pm
Callsign: G-ALGY
Version: 3.0
OS: W7U

Re: Sailing, anyone?

Postby Hooray » Sun Jun 22, 2014 10:40 pm

FG is mentioned on their forums a few times - but nothing specific yet. And I guess it will be a fair amount of work - especially because we do not have certain things (yet), i.e. 1) a boating/vessel FDM, 2) tides/currents and "underwater scenery" (depths profiles). But otherwise, their visuals could obviously benefit greatly from FlightGear, and we'd have a ton of RL scenery coverage.
I guess it would be a matter of looking for similar open source projects that are GPL compatible and which could be used to augment FG accordingly.
Otherwise, Nasal + Canvas is certainly fairly compelling as a platform for any RADAR/ARPA simulation. And we even have support for shaders & effects, as well as multiplayer and multi-screen support - to name just a few areas where BC is said to be still "lacking". And Nasal+AI could certainly provide for interesting traffic scenario/conflicts.

I guess those of us who'd like to see this happen, and be willing to provide support to some extent, should get in touch via their forum for some "networking" :D
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,
Hooray
Help write next month's newsletter !
pui2canvas | MapStructure | Canvas Development | Programming resources
Hooray
 
Posts: 11163
Joined: Tue Mar 25, 2008 8:40 am

Re: Sailing, anyone?

Postby Algernon » Mon Jun 23, 2014 2:41 pm

I've been thinking - would it be possible to alter an existing FDM, cutting down YASim for example, to work in two dimensions only (plus buoyancy & roll) and with hydrodynamic formulae instead of aerodynamic? Basic tidal information is easy to predict, although winds offshore (away from METAR stations) might be more difficult...

I'm certainly keen to join in, and I have a couple of existing ships projects in FG which could be useful for testing. I shall sign up at their forum this evening.
Algernon
FGUK - A FlightGear community in the United Kingdom and Republic of Ireland
User avatar
Algernon
 
Posts: 498
Joined: Sun Jun 27, 2010 3:55 pm
Callsign: G-ALGY
Version: 3.0
OS: W7U

Re: Sailing, anyone?

Postby Hooray » Mon Jun 23, 2014 2:50 pm

I think DFaber and AndersG experimented with Nasal/JSBSim-based "FDMs" for boating - to get this going, I'd probably use Nasal for starters and look for existing open-source projects that already solve the problem, i.e. there are a few boating/yachting sims - and we're already using some stuff from DangerFromTheDeep (submarine sim). So, we'd have to do a little research to find out what's already out there (ideally, C++ & OpenGL based, not any major new dependencies) and then investigate if it's feasible to reuse certain components. But for starters, FlightGear scripting via Nasal should certainly be up to the task. Development-wise, a "ship" would just be another 3D model with a few windows and instruments/views. And all the fancy RADAR/ARPA stuff would be trivial to support due to our extensive Canvas/MapStructure-based 2D plotting support.

But having "underwater scenery" (elevations!) could easily quadruple the size of our scenery :?
Then again, efforts like osgEarth by poweroftwo have demonstrated that it is perfectly possible to implement alternate scenery engines next to the main engine, even without FG having explicit support for this kind of thing. And we've seen osgOcean-related discussions for years: http://wiki.flightgear.org/Implement_OS ... FlightGear

But without any C++ level changes, this would contain quite a number of workarounds and simplifications. On the other hand, even "Advanced Weather" started out in scripting space, and was merely augmented over time - and even today, it's primarily scripted code.

So it's not impossible, the question is how serious people are about this, and what exactly they can contribute in terms of features, knowledge and code.
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,
Hooray
Help write next month's newsletter !
pui2canvas | MapStructure | Canvas Development | Programming resources
Hooray
 
Posts: 11163
Joined: Tue Mar 25, 2008 8:40 am

Re: Sailing, anyone?

Postby DFaber » Wed Jun 24, 2015 10:58 am

Hi Anders,

DFaber wrote in Tue Jan 22, 2013 7:36 am:
AndersG wrote in Mon Jan 21, 2013 5:38 pm:See MTB_20m in my hangar for one example that includes marine propellers driven by the main and auxiliary engines. The link to my hangar is in my signature.


I'll definitly have a look. Thanks!


... it took me nearly two Years to actually test it out, but I did and I'm really delighted!
What Information do I need to edit to adapt it to my Elco PT-Boat or something bigger like a Liberty Ship or a Carrier?
I've looked around in the files and noticed you used Gerris to generate Data. What exactly is that for?

Greetings
Detlef Faber
FlightGear Development:
http://flightgear-de.net

German FlightGear Forum
http://forum.flightgear-de.net
DFaber
 
Posts: 684
Joined: Fri Dec 01, 2006 7:51 pm
Location: Aachen, Germany
Version: GIT
OS: Linux

Re: Sailing, anyone?

Postby Johan G » Wed Jun 24, 2015 12:50 pm

DFaber wrote in Wed Jun 24, 2015 10:58 am:I've looked around in the files and noticed you used Gerris to generate Data. What exactly is that for?

Got curious and looked it up. It is probably something you have been looking for, though you don't know it yet. :wink: Its wiki reveals it is an open source software "for the solution of the partial differential equations describing fluid flow".

Some examples they have to show off capabilities are Wingtip vortices behind a rectangular NACA 2414 wing and Air-water flow around a Series 60 cargo ship. I also noticed Using Blender to create solids for Gerris. It seems very capable.
Low-level flying — It's all fun and games till someone looses an engine. (Paraphrased from a YouTube video)
Improving the Dassault Mirage F1 (Wiki, Forum, GitLab. Work in slow progress)
Johan G
Moderator
 
Posts: 5292
Joined: Fri Aug 06, 2010 5:33 pm
Location: Sweden
Callsign: SE-JG
IRC name: Johan_G
Version: 3.0.0
OS: Windows 7, 32 bit

Re: Sailing, anyone?

Postby AndersG » Wed Jun 24, 2015 6:39 pm

DFaber wrote in Wed Jun 24, 2015 10:58 am:... it took me nearly two Years to actually test it out, but I did and I'm really delighted!
What Information do I need to edit to adapt it to my Elco PT-Boat or something bigger like a Liberty Ship or a Carrier?
I've looked around in the files and noticed you used Gerris to generate Data. What exactly is that for?


Most of the work to get started is generating tables over the static buoyancy forces and moments, and currently, that is what I use Gerris for. The tables cover a set of model configurations (height-agl and pitch and roll angles). In principle, you could also generate hydrodynamic coefficients with Gerris, but that is more complicated to set up and requires considerably more computational resources. There is a README for my Gerris procedure in the c172p-detailed repository.

Something bigger and slower than a MTB should be a bit easier to model since you don't have to worry about planing. You can look at my USS Monitor.
Callsign: SE-AG
Aircraft (uhm...): Submarine Scout, Zeppelin NT, ZF Navy free balloon, Nordstern, Hindenburg, Short Empire flying-boat, ZNP-K, North Sea class, MTB T21 class, U.S.S. Monitor, MFI-9B, Type UB I submarine, Gokstad ship, Renault FT.
AndersG
 
Posts: 2414
Joined: Wed Nov 29, 2006 9:20 am
Location: Göteborg, Sweden
Callsign: SE-AG
OS: Debian GNU Linux

Re: Sailing, anyone?

Postby rastafioul » Mon Sep 05, 2016 8:19 am

Hello,
As I wanted to have a yaw/pitch/roll moving carrier to land the aircraft or the Helicopter on (like in this video https://www.youtube.com/watch?v=bC2XIGMI2kM ) I found this topic.

I tried F172p with different weather condition but nothing happens on the pitch roll yaw when "sea-landed"
I tried MTB_20m.

First, it is fun, congratulations to Anders.
Then I also tried with bad weather (catIIIb minimum, thunderstorm, speed of wind a level 0 set to 10, 50 and 160 knots) as I understood Thorsten said weather was transmitting infos to wave (at least for scenery) but the boat would stay still.

Could this come from the fact I use low graphic definition so I can have rather smooth flying experiences?

If not, in order to have the "wave comportement" would I need to fake the comportement directly using nasal on the AI model (/ai/model/carrier/orientation/yaw - pitch - roll)?
Because to tell you the truth, I doubt to have time to take to understand fdm and create specific fdm for a carrier, check and understand how weather transmits to wave and wave to boat.

Flightgear is so awesome it could integrate sailing experience! anybody contacted BridgeCommand and news from this?
Thanks to every single person who helped and/or still helping to have such a great simulator.
For those who would find any complain to do: help or shut up and buy one!
rastafioul
 
Posts: 18
Joined: Tue Feb 16, 2016 5:55 pm
Version: 2016.2.1
OS: debian

Re: Sailing, anyone?

Postby AndersG » Tue Sep 06, 2016 4:49 am

Wave action is an experimental part of the (air)craft based on the hydrodynamics for JSBSim system. It needs to be enabled manually and is not yet connected to the weather. Point your property browser to /fdm/jsbsim/hydro/environment/ and play with the properties there, e.g. wave-amplitude-ft and wave-length-ft (IIRC).
Callsign: SE-AG
Aircraft (uhm...): Submarine Scout, Zeppelin NT, ZF Navy free balloon, Nordstern, Hindenburg, Short Empire flying-boat, ZNP-K, North Sea class, MTB T21 class, U.S.S. Monitor, MFI-9B, Type UB I submarine, Gokstad ship, Renault FT.
AndersG
 
Posts: 2414
Joined: Wed Nov 29, 2006 9:20 am
Location: Göteborg, Sweden
Callsign: SE-AG
OS: Debian GNU Linux

Re: Sailing, anyone?

Postby rastafioul » Tue Sep 06, 2016 5:32 pm

Nice!... real nice!
it seems that right now, the boat moves mainly on pitch but that is a great start.

Would it need to be possible to add this behavior to an AI ship (carrier or carrier 's escorts)?

What would need to be done?

Would what I have seen be the solution?
http://wiki.flightgear.org/Scripted_AI_ ... ng_the_FDM

Copy AndersG's "MTB_20m-hydrodynamics.xml" code as the fdm, using the C++ thing and then add the nasal under %FG_HOME%/Nasal ?

Ps: maybe I need to open a new topic for this.
Confirm and I shall put a link.
Thanks to every single person who helped and/or still helping to have such a great simulator.
For those who would find any complain to do: help or shut up and buy one!
rastafioul
 
Posts: 18
Joined: Tue Feb 16, 2016 5:55 pm
Version: 2016.2.1
OS: debian

Re: Sailing, anyone?

Postby Hooray » Tue Sep 06, 2016 8:56 pm

these projects usually take a little time, and a rough prototype - as in, having a 3D model, some kind of semi-plausible FDM and an actual use-case.
As far as I know, there are several vessels and some basic "FDMs"

The scripted FDM would work to some degree, but it would not work as well having an actual FDM engine for this kind of traffic.

Note that the scripted FDM approach is primarily about creating AI traffic objects, not entities to be used as the main vehicle.
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,
Hooray
Help write next month's newsletter !
pui2canvas | MapStructure | Canvas Development | Programming resources
Hooray
 
Posts: 11163
Joined: Tue Mar 25, 2008 8:40 am

Re: Sailing, anyone?

Postby PINTO » Tue Sep 06, 2016 9:52 pm

https://github.com/onox/CVN-70 is a carrier that pitches and rolls with the waves.
Actively developing the MiG-21bis (link to repo) (link to thread)

http://opredflag.com is an active flightgear dogfighting community (using a system that isn’t bombable)
User avatar
PINTO
 
Posts: 922
Joined: Wed Oct 21, 2015 6:28 pm
Callsign: pinto
Version: 2016.3.0
OS: Win10

PreviousNext

Return to Development

Who is online

Users browsing this forum: No registered users and 3 guests