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Cloud strange roll

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Cloud strange roll

Postby 5H1N0B1 » Wed Sep 16, 2015 11:03 am

Hi everyone,
Just to start, wheather thing is just awesome, I really like what's done here.
I do not know if there a topic on the same subject, in that case, just delete this one.
So I have a strange effect, but perhaps it's inherent of the way cloud are made, but anyways, this is just to repport the issue :
When I fly, mostly with agile bird, and do some acrobatic stuff, I see that while I'm doing a loopping, some cloud (not all) are rotating in an unrealistic way.
Image
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Hope that can help to improve these beautiful cloud.
See you soon
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Re: Cloud strange roll

Postby wlbragg » Wed Sep 16, 2015 5:10 pm

The short answer is, this is by design. That particular type of existing cloud is a trick. It is basically a 2d sprite or something of that nature, not a real 3d cloud. It is programmed to always face the viewer which leads to undesirable effects at times (specifically when viewed at certain angles to the cloud, up or down).. Someday we may have systems in place and more computing power to go with so we can generate more real time and less trickery.
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Re: Cloud strange roll

Postby Thorsten » Thu Sep 17, 2015 5:23 am

Here's some introduction to how 3d clouds are done in the Wiki.

If you own a gaming-class top-notch GPU, you will find we are actually able to render simple true 3d clouds these days - here's an experiment of yours truly

Image

They just have a very high pain to gain ratio, i.e. look pretty badly and drain tons of framerate - and any improvements drain resources quadratic in accuracy :-/
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Re: Cloud strange roll

Postby V12 » Wed Apr 04, 2018 1:55 pm

Another example of bad rotated clouds created by advanced weather, source live METAR :
Image

Condition :
- take off from KLAX cca N33.93 W118.15
- landed at TNCM cca N18.04 W063.11
- flight log https://fgtracker.ml/modules/fgtracker/ ... ID=7004194

After landing I observed that strange rotated cloud circa 50 degree anticlockwise. Longitudal difference between KLAX and TNCM is cca 50 degs. Is this difference source of that strange clouds rotation ?
I will try other tests and report.

EDIT :
Start with UFO at EGLL (N51.47 W000.45) - clouds normal :
Image

"teleport" to PAJN (N58.35 W134.58) - clouds abnormaly rotated anticlockwise :
Image

"teleport" to OMDB (N25.25 E055.36) - clouds again rotated, but in this case clockwise :
Image
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Re: Cloud strange roll

Postby Isaak » Wed Apr 04, 2018 4:44 pm

My solution to this on intercontinental flights: switch to basic weather for a second and switch back to advanced weather.
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Re: Cloud strange roll

Postby Thorsten » Wed Apr 04, 2018 4:53 pm

Hm, I didn't know that'd work.... I was under the impression that AW and BW basically use the same cloud technology stack (AW just uses an fgcommand add-cloud which utilizes Stuart's cloud rendering system) - it's odd that this leads to differences in practice.

Stuart really needs to comment on that one - I know how I'd hack my way around the issue but that's really not the best solution.
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Re: Cloud strange roll

Postby Clive2670 » Wed Apr 04, 2018 4:58 pm

This effect also happens to me when conducting a "long haul" flight (EGKK to KLAX) for instance
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Re: Cloud strange roll

Postby Thorsten » Wed Apr 04, 2018 5:00 pm

Yes, clouds rotate with the longitude change since start - we've known that for ages, what I haven't known is that BW has a different behavior.
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Re: Cloud strange roll

Postby wkitty42 » Wed Apr 04, 2018 6:13 pm

well, IIUC and see what i think i see, basic weather has those flat bill-boarded clouds that don't have any depth to them... i say bill-board because they're flat to and parallel with the ground... i can understand that switching off AW (allows BW to run, right?) would allow for some properties (variables) to be reset to the current location's orientation... then when AW is started back up, it now pulls the new orientation properties and everything is generated properly...
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"Why not?" said Gurder.
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Re: Cloud strange roll

Postby V12 » Wed Apr 04, 2018 6:35 pm

wkitty42 wrote in Wed Apr 04, 2018 6:13 pm:... then when AW is started back up, it now pulls the new orientation properties and everything is generated properly...

Not. I landed at TNCM, switched BW, then back to AW, click OK and - clouds was again rotated.
- again "take off" from EGLL with UFO
- teleport to PAJN, active AW :
Image

- switched to BW :
Image

- switched back to AW :
Image
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Re: Cloud strange roll

Postby wkitty42 » Wed Apr 04, 2018 10:15 pm

apparently it works for BEL ISAAK according to his post above ;) i've not tried it... i'm busy testing other things :mrgreen:
"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: Cloud strange roll

Postby stuart » Thu Apr 05, 2018 4:02 pm

From memory there's a rotational transform created at start of day based on the longitude that we never update.

I'll take another look when I get the chance.

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Re: Cloud strange roll

Postby V12 » Thu Apr 05, 2018 4:53 pm

Small hint :
In the Nasal console I found message "Coordinate rotation by more than 20 deg... compensating"
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Re: Cloud strange roll

Postby Thorsten » Thu Apr 05, 2018 5:11 pm

Sorry - what's that got to do with clouds?
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Re: Cloud strange roll

Postby V12 » Thu Apr 05, 2018 5:22 pm

I don't know, but there is possibility to some bad compenssation should make effect of the bad rotated clouds. I don't know, I'm not AW developer. This text I found in the file weather_tile_management.nas.
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