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Do that voodooo that you do...

Avsim was kind enought to post a link to some of the ACES team member's blogs. Thanks Avsim, and welcome Avsim readers. I, of course, love Avsim as I am their "favorite arteest and lurker"  ;)

I figure then, it's only fitting that I deliver up some tidbit for our dear reader(s).

One of the things I'm very proud of in the last release of Flight Simulator is our weather environment. I've linked to various papers detailing the weather system (like here) before, so I won't go into what we did again, but I did want to talk a bit about the water environment work that was done. You see, while I was fairly happy with what we shipped, there was one glaring feature that works mostly the way you'd think, but can deliver some mighty... odd results.

We created a brand new sky system, offering up a variety of color palettes to give each day a slightly different hue cast (and sunset). Okay so far as we go.

We created a brand new cloud visuals system. Added a nice little functionality to create wether themes.

Again, okay so far as we go.

The water environment maps switch out depending on time of day, dawn dusk, noon, and so on.

Okay... so we run into a little bit of trouble here. Each sky set (there are ten) can have it's own color "theme" if you will. There is, on the other hand, only one set of water environment maps. The maps mimic what happens in real life, namely the surface of the water reflects the sky conditions (clear through overcast), as modified by surface conditions (calm, glassy, rough, etc). Which means that you can easily generate a disconnect between what the environment map should look like (as described above), and what it actually looks turns out to be-- which is one texture capturing one moment, one color theme, one sky condition.

Examples of where this disconnect can be found (and where we decided that having variation was more important than having uniformly conforming color) are at sunset, where the dusk water environment map maybe yellow, but the sunset is a vivid red.

Okay, you say that's no big deal.

Here's the big "bug." Mix these three things together: weather theme, time of day, and water environment map. What do you get?

Milk.

Okay, not really milk, but you get a "perfect storm" of sorts.

What's the worst time of day in Flight Sim from an aesthetic point of view?

Noon.

The sun is almost directly above, so shading is at its most uninteresting (start out in the mountains in summer at noon. blech! now advance the time to say, 4:30 pm. VoilĂ ! C'est mangifique!). It's also very bright.

Okay, now add in a nice weather theme. Let's put in "fair weather" for our nice sunny noon day. So which water environment map do you get? Do you get env_highnoon.bmp loaded?

No.

You instead get env_overcast.bmp. Yep, overcast.

Why overcast? Well, the wetaher theme fair weather calls for a cirrus layer of 6/8ths coverage. We load the overcast environment map when cloud coverage gets pretty thick (starting at 6/8ths actually...), which in the real world tends to make water look a little grey. Sometimes purpleish, sometimes greenish, sometime yellowish, and so on, but not so blue skyish, that's for sure, so we load a different environment map. We don't have a seperate environment map for each sun state (morning, noon, dusk, etc), only one overcast, so it sort of has to look good at about anytime of day (don't forget, we the water gets some lighting too).

Starting to get the picture?

When you load the default  flight in Flight Simulator, the default time of day is noon. Our "nice" wetaher themes all have cirrus cloud coverage of 6/8ths-- looks fine, overcast cirrus isn't exactlly overcast, if you know what I mean. So you load the overcast water environment map (already kind of a weird color), light it at its brightest (noon), and have lots of blue sky in the scene.

What do you get?

Milky water.

sigh.

So now you know.

If you haven't already, take a look at some of these neat add-ons for the sky and/or water environment for Flight Sim (some are for FS2002, but should work fine in FS 2004):

Active Sky

Bill Lyons water

Flight Environment

Environmental Water Textures Library,

 Oceanfx.zip and Oceanstx.zip

in addition, you might try a library search at Avsim for any of the following names:

Daniel Buechter, Kevin Rangel, and Ed Truthan.

There are many more of course, but I can't do all the work for ya now can I?

Published Friday, October 28, 2005 6:55 PM by pixelpoke

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Comments

# re: Do that voodooo that you do...

J,

I concur on the suggestion of Flight Environment. I find it to be a most pleasing utility at providing unique variations of clouds, water, and sky lighting that can be experienced every time you fly in the sim!

Great stuff!

O
Saturday, October 29, 2005 12:37 AM by OwenHewitt

# re: Do that voodooo that you do...

Thanks for mentioning Active Sky!
Saturday, October 29, 2005 12:51 AM by Jim

# re: Do that voodooo that you do...

Jason, we missed you in San Diego guy! You are coming to Washington D.C. next September, right? :)
Saturday, October 29, 2005 10:11 AM by Tom Allensworth

# re: Do that voodooo that you do...

Thank you for the insight, and congrats on a very fine product. Weather is a dynamic part of flying and I hope that future release(s) if possible, may focus more on the realism of weather, particularly winds and density altitude. All those pretty puffy clouds and thunder storms that FS9 and other add ons provide, are avoided like the plague in the real world. If you can simulate like real world flying inside a cloud, I think it would be a nice awaking for some of the desk top flyers. Just a thought. SD
Saturday, October 29, 2005 12:31 PM by simdriver

# re: Do that voodooo that you do...

Tom,
Maybe sometime next year I'll be able to make a trip...

Of course it'll have to be by train or ship, what with the not flying and all.

;)

Someday though. Someday.

Cheers,

Jason
Saturday, October 29, 2005 10:28 PM by pixelpoke

# re: Do that voodooo that you do...

Simdriver:

Thanks.

Weather is certainly important. We've made a good beginnig, but I know we *all* want more.


Jason
Saturday, October 29, 2005 10:30 PM by pixelpoke

# re: Do that voodooo that you do...

Hi,
Thanks Jason for your excellent works and the links about Active Sky.


Chris
Tuesday, November 01, 2005 3:39 PM by Chris Willis

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