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Old 06-29-2017, 11:26 AM   #16
C3PO
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Exact reproducability is not going to be important for the "average" user, but essential for some developers.

Would it be possible to use random(ish) local effects (gusts etc.) and then add a [Record local weather]? This way developers can use replays to replicate exact conditions.
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Old 06-29-2017, 11:30 AM   #17
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Originally Posted by C3PO View Post
 Exact reproducability is not going to be important for the "average" user, but essential for some developers.

Would it be possible to use random(ish) local effects (gusts etc.) and then add a [Record local weather]? This way developers can use replays to replicate exact conditions.
What about procedural techniques, where the seed of the random generator is saved?
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Old 06-29-2017, 12:29 PM   #18
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I still believe that exact reproducibility will come from a stable global and local climate system OR through the custom wind options. Local gusts can be set to 0 to have a ripetitive environment or to a preferred number to see how the systems react to random inputs but that's it. I think that this is how the flight simulator like fsx or others works actually.
If you're checking the atmospheric autopilot and you want to see how it works with wind you can either set gusts to 0 and see if it works properly with seasonal and local winds (which will always be the same for a certain date and time), if you want to see if it works with particular winds (strong crosswind for example) you set your wind custom settings to strong wind from the cross direction. If you want to see if it reacts well to gusts, just put the gusts you want and check, but that's only for moments here and there, once the global system works, it won't be necessary to have the very same gust at the very same moment.
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Old 06-29-2017, 12:39 PM   #19
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 I still believe that exact reproducibility will come from a stable global and local climate system OR through the custom wind options. Local gusts can be set to 0 to have a ripetitive environment or to a preferred number to see how the systems react to random inputs but that's it.
Well, I know that this is a very weak argument, but such a core feature would be the first I'd advice OMP users to turn off. It would make syncing 2 sessions practically impossible if the one user gets shaken through in a gust while the other experiences no wind at all while flying formations.
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Old 06-29-2017, 01:09 PM   #20
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 Well, I know that this is a very weak argument, but such a core feature would be the first I'd advice OMP users to turn off. It would make syncing 2 sessions practically impossible if the one user gets shaken through in a gust while the other experiences no wind at all while flying formations.
that would happen anyway if users choose different wind options (no wind, realistic wind, custom wind). I think it would be enough just to agree among users to set gusts to 0 for realistic, to agree on the custom settings if custom, or simply agree on no wind.
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Old 06-29-2017, 02:03 PM   #21
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I again say that regarding that IMO there should be a global climate model with seasonality change, added to some local variation and some random super-local effects
I'm not sure what you're after.

Compared to the delta-v requirements of launching into a different inclination or from a different latitude, the requirements to compensate for wind drift assuming average winds are negligible. If you're flying by hand, the errors you make will be far larger than wind drift, and any automated system will eat such errors for breakfast.

Similarly, stratosphere winds are not a concern at all for Shuttle entry trajectories. Windspeeds are just too slow compared with the velocities involved. The ranging errors they introduce are negligible compared with other effects and can be compensated easily (and again are much smaller than the ranging errors I get piloting by hand).

In aviation weather, if you're after immersion the experience is not so much in the average, but in singular events far from the average. Jet streams in the stratosphere, weather in the troposphere. But that's not really captured by an average plus some variation. If you're after the experience during approach and landing, focus on getting the altitude dependence of tropospheric winds and the boundary layer physics correct - that's where it can actually be felt.

A global averaged climate model is nice, but you'll have to log and compare trajectories with analysis software to see what it did.
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Old 06-29-2017, 02:26 PM   #22
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Originally Posted by Thorsten View Post
 I'm not sure what you're after.

Compared to the delta-v requirements of launching into a different inclination or from a different latitude, the requirements to compensate for wind drift assuming average winds are negligible. If you're flying by hand, the errors you make will be far larger than wind drift, and any automated system will eat such errors for breakfast.

Similarly, stratosphere winds are not a concern at all for Shuttle entry trajectories. Windspeeds are just too slow compared with the velocities involved. The ranging errors they introduce are negligible compared with other effects and can be compensated easily (and again are much smaller than the ranging errors I get piloting by hand).

In aviation weather, if you're after immersion the experience is not so much in the average, but in singular events far from the average. Jet streams in the stratosphere, weather in the troposphere. But that's not really captured by an average plus some variation. If you're after the experience during approach and landing, focus on getting the altitude dependence of tropospheric winds and the boundary layer physics correct - that's where it can actually be felt.

A global averaged climate model is nice, but you'll have to log and compare trajectories with analysis software to see what it did.
I don't know if i expressed myself not clearly, but what you're saying is basically the same of what I'm stating.

I'm saying that, since Dr Martin is willing to introduce a wind model inside the sim, a good global /seasonal model is enough, that local definitions may be added and that gusts may be random. That the system should have some options so users may customize it if they want to (see reproducibility for debug, OMP or other needings)

And I'm saying that random events reproducibility IMHO is not mandatory at all, since once the global/seasonal model is fixed you'll already have general reproducibility granted.

basically I'm the guy who's saying that it's enough to keep things "simple" for this
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Old 06-29-2017, 02:30 PM   #23
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 that would happen anyway if users choose different wind options (no wind, realistic wind, custom wind). I think it would be enough just to agree among users to set gusts to 0 for realistic, to agree on the custom settings if custom, or simply agree on no wind.
Sure, settings I can synchronize between clients. As I said, random gusts would be the first thing I have to turn off, with no option to turn it on, because it is not reproducible and just... well... random.

Anyway, the possibility to synchronize two physics engines is hardly what the average user will want to have, so it is a weak argument. My vote is for the reproducible system, though.
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Old 06-29-2017, 02:35 PM   #24
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What about procedural techniques, where the seed of the random generator is saved?
That was pretty much my first thought when I heard "reproducability".

Doesn't exclude a global model either. Just have local variations as a function of date and seed.
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Old 07-14-2018, 09:00 AM   #25
fatcat
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From a novice point of view, I have turned off the atmospheric wind effects parameter simply to get the DGIV to run straight down KSC 33 on take off.
Could I change the wind direction to headwind???
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Old 07-14-2018, 09:04 AM   #26
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I wish that we could toggle between a surface-relative and an air-relative flight path marker in surface HUD.
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Old 08-21-2018, 10:53 AM   #27
Abdullah Radwan
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Why not use realistic weather from airports (Called METAR) and upper wind and cloud data to make realistic weather data?

Some links:

http://metars.com/

http://weather.uwyo.edu/upperair/sounding.html

https://www.weather.gov/jetstream/cloudchart

https://www.simbrief.com/system/dbquery.php
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Old 08-21-2018, 11:50 AM   #28
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 Why not use realistic weather from airports (Called METAR) and upper wind and cloud data to make realistic weather data?
Because it would not be deterministic. This means, depending on your timewarp or going backwards in time, you would get different wind speeds.

Also, you can only get present wind and not historic wind data.

EDIT: And worse, because of the update intervals of the weather services, you can expect 3 hours of the same wind, even if it is completely different in reality because of the local wind field. Do you know a bit about sailing, especially sailing on lakes?

Last edited by Urwumpe; 08-21-2018 at 12:09 PM.
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Old 08-21-2018, 01:19 PM   #29
Abdullah Radwan
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 Because it would not be deterministic. This means, depending on your timewarp or going backward in time, you would get different wind speeds.

Also, you can only get present wind and not historic wind data.

EDIT: And worse, because of the update intervals of the weather services, you can expect 3 hours of the same wind, even if it is completely different in reality because of the local wind field. Do you know a bit about sailing, especially sailing on lakes?
Good point about time wrap, I didn't really think about it.

These links are from a quick Google search, so you can get a better result. As a flight simmer, one of the available weather engines allows historical dates up to 6 years. While there is a lot of limitations (Like you need to connect to the internet), it remains a lot better than the current implementation. Maybe experts had a better approach.

I don't know anything about sailing, but these services are the same which real aviation and flight sims relay on it. If we want a reasonable accuracy, Orbiter should do it the same way the flight simulator does.
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Old 08-21-2018, 02:57 PM   #30
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Do you know a bit about sailing, especially sailing on lakes?
Yeah, that usually looks like "there's no wind". "There's still no wind!". "I think there will never be wind!"
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