My head is in the clouds...

[Pilotasso]

Hi guys.

 

I was thinking, I never ever saw any decently modelled clouds in any sim-ever.

 

There are various types of clouds, but SIM’s have always had same type of unconvincing looking generic clouds.

 

And they all looked bad, I mean in an actual aircraft you can almost reach ant touch clouds however in any SIM they look like an amalgamation of round textures that are so faded away you cant tell exactly the transition when you cross through one. I think they are all 2D with fluffiness haze for visual deception.

 

Also there are clouds that should be avoided due to internal conditions to them. This has never been modelled either and would be lots of fun.

 

 

Dynamic weather would also be well in hand with this though I guess would be much harder to marry it with complex cloud models, granted.

 

Always wondered why this has been left in such primitive shape with not much evolution to see in every iteration of this kind of software with the increase of computation power for the last 20 years! Are there any plans or ideas to change this?

[coolts]

FSX had very impressive clouds. A massive FPS killer though, and more than a little glitchy. The main issue is the huge processing involved in modelling any sort of dynamic weather system.

 

A friend of mine had a hand in modelling the BBC weather system, made in New Zealand, (the newish one with CG effects), and even though, the end view is simplified for viewers, the huuuuge amount if processing power required to keep it running would put most comms rooms to shame).

 

In that light, the most we can hope for, unless you just want a weather simulator with a few add on planes, is going to be smoke and mirrors. Mind you, there are no limits to what smoke and mirrors can achieve, just look at the film industry!

 

if i could fly my F-15 to iceland right now.....

 

now theres some clouds!

Edited May 20, 2010 by coolts

[Kuky]

Storm of War should raise the bar in clouds and weather simulation in a flight sim I think :)

[Pilotasso]

I was thinking a normal 3D model for clouds but with special shaders to avoid looking at a floating solid. I think with DX10 that is possible without the need of a supercomputer.

[coolts]

The demo screens of the DX10 version of FSX looked stunning, before it was cancelled. I believe that there are a lot of GPU enhancements that will hand off the processing duties in more efficient ways with DX11+. It’s the old problem of dev time though. What would you rather ED spent time on, the clouds or the planes?

 

SOW looks like it may hopefully raise the bar in terms of environmental modelling, when it ever comes out, but I wonder if they are doing it all in software as its been in development since the DX9 days or so i believe, so cant be using the newer hardware effects. I must say, the demo trailers for that have me very interested in WW2 combat again.

 

Mind you, waiting for Devs to start using advanced shaders / tessellation techniques made possible by advances in DX technologies and GPU may become irrelevant as the era of "cores" could give Devs a realistic and quick way of handling such advanced algorithms.

 

Take the latest FC2.0 patch which effectively hands off all the sound engine chores to a separate thread / core. With quad cores becoming commonplace and 6 cores released, devs taking gambles on GPU technologies may be a thing of the past. Just assign your environment threads to a separate core!

 

If Intel have their way, monolithic GFX cards could be on their way out, (cough 'larrabbee' cough)

Edited May 20, 2010 by coolts

[winz]

FSX does have DX10 support, but it doesn't look nearly as good as those marketing screens, what's worse, it's kinda buggy and lot of people have issue with flickering textures in it.

 

The best clouds I've ever seen in a sim were created by REX 2 - weather engine for fsx

 

http://www.realenvironmentxtreme.com/cockpit/cockpit.html

 

The hardest thing about clouds is - every one is different, no two look really the same.

[Pilotasso]

they do look awsome...from a distance, it doesnt show up close. :)

[Case]

Always wondered why this has been left in such primitive shape with not much evolution to see in every iteration of this kind of software with the increase of computation power for the last 20 years! Are there any plans or ideas to change this?

This is because they daylight sky with haze and clouds is very complex to model because of their transparency and the scattering that occurs. Accurate modelling would involve solving for complicated physics where you are essentially solving the radiative transfer equations in the presence of water, in the form of clouds or other, and dust in the atmosphere, combined with Rayleigh and Mie scattering.

 

These equations can be solved, but they will take quite some computational power. Add to this the fact that there are no easy ways to simplify the equations, and you are left with the things you are describing, i.e. clouds and haze and sky colour that do not look natural.

[Moa]

Raleigh and Mie scattering can be done in real-time for the atmosphere using shaders. Please see the paper by R S Nielsen (and references) where he compares the sky from ground and from high altitude (he's got a mate who flys F-16s for Denmark) at:

http://www.aj-productions.de/fsdeveloper/category.php5?category=Sky

 

I've posted this link before in a different ED thread which talks about the same problem, and since it answers the same questions I've posted again. Apologies if you already read my earlier post.

 

So, the sky background can be physcially modelled in real-time. The problem is only in the clouds. All flight sims I've seem seem to use billboarded textures for the clouds. The cloud texture is generated using a 'plasma-like' fractal map. You can see this is so if you've ever had graphics glitches and seen the texture rendered incorrectly.

 

Using 'texture particles' to render cloud might work, but the framerate cost might be too high unless you had a second GPU. Using particles directly wouldn't work as it is too expensive at the moment.

[CyBerkut]

Just got an e-mail announcing a new add-on for X-Plane:

 

http://store01.prostores.com/servlet/x-planestore/Detail?no=222

 

REX - Real Environment Xtreme. I just looked at it briefly. I didn't notice any indication about how it looks when you get up close, or into, the clouds.