Hi Curt,
I'm working on implementing contrails, using both particles and submodels,
and I'm seeing the same bug. I also see that particles do not move in the
direction indicated by the windsocks. I have long since reported that there
seems to be an error in the particle wind - I think that the error is in
OSG. IIRC there was some misunderstanding at one point if wind direction was
from or to!
I hope that the submodel wind is correct, but I will look at the code again.
Vivian
-----Original Message-----
From: Curtis Olson [mailto:curtol...@gmail.com]
Sent: 17 July 2010 19:17
To: FlightGear developers discussions
Subject: Re: [Flightgear-devel] weather conditions and winds aloft
notworking correctly..
Hi Torsten,
While we are on the subject, I have two dumb, but related questions ...
1. I do some UAV work and at times collect some real world flight test data.
It would be really nice to be able to capture the current metar data off the
internet at the time of the flight, save it into some simple form along with
the flight data, and then later when I replay the flight data, use the saved
metar data for the weather conditions. Is there a way to do this now? Does
it work? In the past when I've tried to enter metar strings into the
Environment->Weather Scenario dialog box, I haven't been able to get
anything to work ... and I'd like to automate this at least through command
line options if it's possible?
Here's an example video replaying a real flight in FlightGear.
http://www.youtube.com/watch?v=toR9UO_Dafc
You might notice that partway through the video I turn the smoke emitter on.
This is one reason I'd like to have relatively closely matching weather to
the original flight conditions ... so that the smoke drift is in the correct
direction relative to the crab angle and everything is mostly self
consistent. (obviously it won't be perfect if the closest weather reporting
station is several miles away and the weather report was from an hour ago,
but it's better than nothing ...)
2. This brings me to my second question which might be a bug report? It's
my understanding that an aircraft is flying relative to it's local air mass.
So if I emit smoke and the smoke drifts in the same air mass, then from the
perspective of the aircraft looking backwards, the smoke should come
straight out of the tail in line with the aircraft (even if it's crabbing
relative to the ground.)
What I see instead is that the smoke also drifts relative to the path of the
aircraft in the air mass, and this can't possibly be right. The amount of
error seems to scale in proportion to how strong the winds are.
I think there must be some sort of units conversion or scaling problem (?)
when the local wind vector is applied to submodels and particles?
Is this issue within your domain as the weather master?
Thanks!
Curt.
On Sat, Jul 17, 2010 at 12:08 PM, Torsten Dreyer wrote:
> Not the best quality but readable, hopefully those will demonstrate
> the problems pretty clearly.
>
> http://www.flickr.com/photos/jmburbach/sets/72157624393619399/
>
> I'm also unsure why you bring up altitude above ground, as winds aloft
> are stated above sea level and in true headings are they not?
Congratulations! You found a - probably long standing - bug!
The environment interpolation did not work above the second layer due to a
bug
probably introduced by myself some long time ago.
Thanks for reporting and the excellent test case with the screenshots.
BTW: you don't have to type in your environment setup at every program
start,
just use the attached file and start
fgfs --config=path/to/aloft.xml
Please check and report if the issue is gone with the latest git pull.
Torsten
----------------------------------------------------------------------------
--
This SF.net email is sponsored by Sprint
What will you do first with EVO, the first 4G phone?
Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first
_______________________________________________
Flightgear-devel mailing list
Flightgear-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/flightgear-devel
--
Curtis Olson: http://baron.flightgear.org/~curt/
------------------------------------------------------------------------------
This SF.net email is sponsored by Sprint
What will you do first with EVO, the first 4G phone?
Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first
_______________________________________________
Flightgear-devel mailing list
Flightgear-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/flightgear-devel
