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Dreeew

True cumulus for thermals

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Hi

First of all I have to say thank you to Peter. Without CumulusX I would stop simming years ago! Thanks for a great software.

So, anyway, I think I succeded to make real cumulus clouds for thermals. When I saw Wingman's post in this topic http://www.forum.aer...showtopic=26567 I decided to give it a try and installed sdk and gmax.

So basically I made a dummy 3D object and attached an effect to it. The effect is very easy to edit so you sure can make them look even better. The effect uses your actual cumulus graphics, so in theory it's compatible with every addon. You just have to copy cumulus01.bmp from Textures to Effects\Textures and the effect can use it.

2009112212214421.jpg

Hope you enjoy it

Alex

Instructions

1. Unzip Thermal Model.zip to

Microsoft Flight Simulator X\SimObjects\Misc\CumulusXCloud and overwrite existing files.

2. Copy fx_therm_cloud01.FX to

Microsoft Flight Simulator X\Effects

3. Go to Microsoft Flight Simulator X\Texture and find cumulus01.bmp. COPY this file to

Microsoft Flight Simulator X\Effects\Texture

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Hey Dreeeeww this sounds interesting - I've used GMax to create models but I've never created an effect - any further comment you could give to explain this technique to a modelling nooob ? I'm currently browsing the effects SDK (here) but a basic overview of how the technique fits with Cx would be really helpful...

B21

**edit I guess my basic question is to clarify this sequence:

(1) you create some basic (invisible?) simobject just to hold the attach point for an effect? Or is the cloud effect placed itself directly at a lat/long/alt ?

(2) if a simobject then in gmax you associate an effect with that attachpoint?

(3) you create the effect which is basically a .fx file referencing .bmp files in the ParticleAttributes section?

The bits I really don't get are

- although I see you can 'emit' 3D library objects, are effects really mostly just BMP textures that can be rotated to the viewer? I.e. is that the technique you're using for clouds?

- I see the sdk mentions effects definitions as 'emitters' and 'particles' - how does that map to your cloud technique? Out of interest, can an emitter move effect particles relative to a user aircraft, like tracer bullets (nothing to do with clouds, I know)?

- how do you trigger an effect if it's not "landing on dirt" etc which are automatic triggers in FSX ?

thanks... B21

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Hey Dreeeeww this sounds interesting - I've used GMax to create models but I've never created an effect - any further comment you could give to explain this technique to a modelling nooob ? I'm currently browsing the effects SDK (here) but a basic overview of how the technique fits with Cx would be really helpful...

B21

**edit I guess my basic question is to clarify this sequence:

(1) you create some basic (invisible?) simobject just to hold the attach point for an effect? Or is the cloud effect placed itself directly at a lat/long/alt ?

(2) if a simobject then in gmax you associate an effect with that attachpoint?

(3) you create the effect which is basically a .fx file referencing .bmp files in the ParticleAttributes section?

The bits I really don't get are

- although I see you can 'emit' 3D library objects, are effects really mostly just BMP textures that can be rotated to the viewer? I.e. is that the technique you're using for clouds?

- I see the sdk mentions effects definitions as 'emitters' and 'particles' - how does that map to your cloud technique? Out of interest, can an emitter move effect particles relative to a user aircraft, like tracer bullets (nothing to do with clouds, I know)?

- how do you trigger an effect if it's not "landing on dirt" etc which are automatic triggers in FSX ?

thanks... B21

1. Yes. It's a 10x10cm transparent cube. The effect is attached to the object

2. Yes.

3. I took Wingman's modified forest fire for a start and modified everything. I never did any addon or effect so I needed something to see the syntax and stuff.

The bits I really don't get are

- although I see you can 'emit' 3D library objects, are effects really mostly just BMP textures that can be rotated to the viewer? I.e. is that the technique you're using for clouds?

- I see the sdk mentions effects definitions as 'emitters' and 'particles' - how does that map to your cloud technique? Out of interest, can an emitter move effect particles relative to a user aircraft, like tracer bullets (nothing to do with clouds, I know)?

- how do you trigger an effect if it's not "landing on dirt" etc which are automatic triggers in FSX ?

Sorry cant answer the last 2 questions cause well.. I never made an effect :) But ye, what you see in FSX are Cumulus sprites, they are all the time oriented to user (all but one axis), long story short they behave EXACTLY like FSX clouds. There's a small emitter in the center of the cloud wich emits particles - individual cloud parts with a variable lifetime. So these thermal cumulus do change a little over time, they arent fixed.

Anyway, I think there might be a bug, I'll take a look this evening and make the 2nd version. Also I'll make a simple tutorial about UVs mappings since all cloud addons dont have the same cloud types in cells. That means this effect DOES work with any clouds (default, REX, FEX, any resolution) but results may vary, I'll write a short tutorial about how to get more control over it and make it look exactly like you want.

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Oh and by the way. I need a little help from real life glider pilots. Is there any difference between a thermal cloud and a non-thermal cloud? I mean, right now it's really tough to see the difference between thermals and ordinary clouds. So I can make them lighter or darker or bluer or more transparent or smaller, you people tell me!

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Oh and by the way. I need a little help from real life glider pilots. Is there any difference between a thermal cloud and a non-thermal cloud? I mean, right now it's really tough to see the difference between thermals and ordinary clouds. So I can make them lighter or darker or bluer or more transparent or smaller, you people tell me!

Thanks Dreeew. Re 'thermal' clouds the fact of the matter is that pretty much all Cu's have thermals under them and it just depends on when you get there relative to that individual thermal lifecycle, and the Microsoft Cu's look pretty much like Cu's that should have thermals under them but don't. So on that basis I would say having Cx Cu's that look like Microsoft Cu's is not such a bad thing. However, active Cu's generally have well defined flat bases - in fact many are actually concave on the underside - where the default Msoft Cu's are a bit wispy on the underside. Clouds with active thermals are generally a bit darker on the underside but this is 100% because of their stronger vertical development (i.e. they're a bit taller and haven't started to decay) so whether that should be simulated by darker shading or whether FSX would take care of this based on the depth of the cloud I don't know.

I haven't looked at your 'effects' clouds yet - how do they differ from what Cx does anyway? Default Cx clouds do seem to change abruptly from one bitmap to another.

B21

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This looks really interesting!

But is it possible to make the clouds bigger? the clouds in you screenshot seem to be just one polygon flat, and really small.

(Haven't tryed them, too, because I have some problems with cumulus with win7 at the moment.

Bests Joachim

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The clouds in the screenshot are actually default fsx clouds, fair weather theme with few thermals. And yes it is possible to make them bigger.

Now there is a bug with transparency in FSX and I see no solution. Still looking.

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Hi Dreeew,

congratulations, very impressive. I like the fade-in very much. I would not even have thought that even FPS impact is negligible. I did not test different time of the day so far. With the original clouds it turned out very tricky to achieve a compatible look throughout most of the day. As Ian commented, real thermal clouds have a relatively sharp base when active. When they start to look fuzzy, the thermal is usually already over.

Still it would be nice to have also the different sizes and shadows if desired. You could also try to use an "inverted" effect to fade out the clouds at end of life. This phase lasts 3 minutes at this time. At this time it seems that the cloud simply restarts when size changes or when it is switched to decay phase.

Regarding the transparency issue, I think one part is a fundamental problem with transparency. Usually graphics card use a Z-buffer to ease culling of occluded objects, unfortunately that doesn't work for transparency. The solution is to pre-sort objects and draw distant object first and the nearest object at last, leaving the z-buffer untouched. This means you have to sort all objects by the CPU in advance.

As FSX treats composite objects as a single one this leads to unsolvable conflicts if objects intersect each other. It seems that the normal FSX clouds are grouped into huge objects, and individual user objects are placed somewhere in between. If you come close enough to your user object, its center is actually closer than that of the large FSX cloud group and z-sorting works. If you move away, or look from a different perspective the cloud group may get priority, drawing over the user object. Sad, but that's the way it is and there is no simple solution for that other than sorting each transparent drawing primitive individually.

If you have a non-transparent object, the problem does not occur, as the z-buffer of the graphics card does the job for free.

regards,

Peter

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Hi Peter thanks

About the form and the size - they arent actual fsx clouds but only use cloud graphics. It must be feasable to make sharper base though. The effect is fully customizable.

About the transparency - I didnt get much but its bad isnt it? I mean we cant do all what you just said with an effect, or can we? The fx file only contains simple parameters for emmiters and particles, there is no way to program special z-buffer tricks with it.

Oh btw, effect placed manually with xml still causes transparency issues. It's going nowhere.

But I have an idea. What if we.. it's coming.. .. wait for it .. :ph34r: .. delete all fsx cumulus :D and only use stratus, cirrus and Cx thermals?

-B21 mentioned above that all cumulus have thermals so it kinda makes sense

-Stratus look awesome actually and are underrated :D especially when they have some decent depth and ASA can be configured to use stratus only (dunno about REX)

-Cx has to generate more thermals - like 10x what we have now but most of them should be weak (performance and FPS hit is the big question here but I think it should be OK)

-Oh did I forget to mention this :) - I've tested the effect with stratus and it's BUG FREE so far, will keep testing.

Several set of cumulus/effects can be done for variety etc etc

Also, Cx doesnt generate any thermals when there are no cumulus in scene, and even unblue doesnt help, so I'm testing with manual placed effects or FX Tool.

Tell me what you think about it.

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I think, switching off all FSX standard cumulusclouds would be the best.

It is rare that you get fooled by a good looking cumulus in real life. Why should it be real to get fooled by clouds looking exactly like the thermal clouds in FSX?

If there will be many variations You will not be able to see if you use Only "clear skies" with cumulusX!, or "fair weather" without.

Cheers Joachim

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I think, switching off all FSX standard cumulusclouds would be the best.

It is rare that you get fooled by a good looking cumulus in real life. Why should it be real to get fooled by clouds looking exactly like the thermal clouds in FSX?

If there will be many variations You will not be able to see if you use Only "clear skies" with cumulusX!, or "fair weather" without.

Cheers Joachim

Yeah I 100% agree - *if* the performance is adequate *and* the effects Cu's look good enough then I'd be happy with just CumulusX Cu's. BUT I tried increasing the density of Cx thermals but had quite a performance hit. In the UK the Cu's and the thermals are quite close together but vary in strength and often many are not very strong but you can pick and choose - the Cx environment has the thermals very sparse in comparison. I'm assuming the cmx parameters give us all the flexibility we'd need for the Cu/thermals...

B21

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But I have an idea. What if we.. it's coming.. .. wait for it .. :ph34r: .. delete all fsx cumulus :D and only use stratus, cirrus and Cx thermals?

-Cx has to generate more thermals - like 10x what we have now but most of them should be weak (performance and FPS hit is the big question here but I think it should be OK)

Also, Cx doesnt generate any thermals when there are no cumulus in scene, and even unblue doesnt help, ...

Hi Dreeew,

look on page 12 in the CumulusX! manual to see which weather conditions produce thermals, actually stratus without cumulus does not. Still you may have cirrus and blues skies plus "Unblue". Intention is to have reasonable thermal conditions in accordance with FSX general weather, in particular also with real weather.

10x more clouds would crash FPS, so I'm afraid that one has to stick to the built-in cumulus to get a sky populated with sufficiently with inactive clouds plus the CumulusX! clouds in addition.

Your last screenies look awesome!

best regards,

Peter

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Yep I see what you mean, using only fx-cumulus would mean we cant use real weather or at least not in the way we used to.

I had a performance hit with the latest modifications of the fx file but that was due to the size of the effects and not their quantity. They're just too big, it was basically an fx-generated overcast.

Well anyway I get your point about the weather, I've read this part of manual yesterday and sadly ye theres not much we can do.

Thanks again for Cx :)

Alex

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This is no overcast, this is how it should look.

A W E S O M E ! !

If this is possible without a performance hit, or a minimized one, it would be really cool.

Ofcourse it would be possible to use it with real weather.

We must only find a way to delete the original FSX clouds. WHO needs them any longer, if this works???

Even for motorplanes thermals increase the realism. You feel them in motorplanes, too.

This could be a complete fair weather exchange!

Very well done

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Ok first of all fps hit wasnt due to fx size, but to particle generation rate, I've changed it for my tests.

But I have to make them smaller anyway! Right now Cx scales the "cumulus object" (my 1x1m dummy cube) to match the size of the thermal. The fx is way bigger, so basically when the cube isnt in sight the whole cloud disapears. It's not a big problem, I have to scale them down like 3x and it'll be fine.

OR if I can disable object scaling in Cx (how?) I can avoid this with huge dummy objects, like 1x1km transparent boxes. Not to mention with cumulus that big you'll have hard time finding the thermals under them :) But anyway it's technical stuff and it doesnt matter, I just wanted to show fx clouds can look good.

The wheather issues are actually problematic. ASA can generate stratus instead of cumulus but no thermals with stratus. So I guess if we replace fsx clouds textures with transparent ones or somehow disable them in a different way we'll get real winds + real visibility + real temps + fake clouds :)

I'll take a look this evening, maybe I can make stratus look like cumulus :)

edit: oh we reaaally need stratus, if fsx has to render 60 miles of fx-cumulus in all directions we'll get 3 fps at best, thats a fact.

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forget ASA...

developing for a product and 3 additional external 3rd partie products will never be a good developement. Especialy if you all change the same files.

So focus on stock FSX.

Hard to find thermals under clouds...

Hmm, in fact this is real. The thermals aren't as big as the clouds in real life. The appear at one side of the cloud, or the middle and you think it is one side, because of the wind, and get bigger the nearer you get to the cloud.

http://www.aerospaceweb.org/question/nature/q0253.shtml

There is a nice description.

So please don't think there are no hughe thermal clouds. In fact I had thermals under a real overcast several times. Not strong but present.

There are so many things possible in real life...

The last pictures look far more realistic to a real glider than the first one (start of the thread).

Cheers Joachim

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Thanks for the link Joachim, it's very instructive.

Anyway I'm redoing *.cld files to make stratus look like cumulus. Interesting discovery - stratus clouds arent sprites in FSX but 3D objects! The bad news their orientation seems to be "hardcoded" - I guess, I cant change it. There are variations of course like +-20 degrees but mainly they are paralel to the ground. It will be hard to make them look as cumulus. I have to say though they look really good for geometry-based clouds.

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20091125204236317.jpg

New fake cumulus/former stratus (custom CLD file & cumulus textures) + thermal cumulus.

Fx are manually placed. Basically now the only problem is Cx not making thermals w stratus and no cumulus in weather description. :)

...

I guess you can figure out easily right now where is stratus/fake cumulus and where are thermals. I'll make them more similar, but so far I'm really happy with stratus (given the fact they werent ment to look like this at all)

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New modified stratus

newstratus.jpg

New cumulus

newcumulus.jpg

All put together via xml scenery file

togetherg.jpg

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1. Real world weather

2. To have some cloud coverage! Cx generates thermals in a certain range, after that it's blue sky..

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