10 replies to this topic

[rouncer]

Ive got this fairly nice looking landscape.


but its lacking a few things, like maybe a decent sky.

Is there any tutorial or could anyone just give me a few clues how to make a really jawdroppingly stunning sky?

Like one with really nice clouds or something, just some keywords i could put into google would be good enough... sorry i dont even know what any algorythms are called even, im totally without any knowledge.

Just something I could look at, maybe half understand and implement something half original myself is probably what Id do... the landscape, grass and hills and path have all been implemented originally by myself, so maybe I could have a go at a sky as well, but a few hints would be nice.

[alphadog]

A good starter point, if only for keyword generation:
http://www.vterrain....osphere/Clouds/

[rouncer]

Thanks for those alphadog, i guess I need the ones that are for viewing, not for flying into... thankyou. I guess I should have thought of "clouds" not sky... i looked up sky on you tube and just got nothing.

[Reedbeta]

Try also looking up "atmospheric scattering". Some people have built sky models based on physical simulation of how the light scatters in the air. This can generate the color of the sky as it varies based on time of day and the direction you're looking. (Ever noticed the sky on a clear day is deep blue at the zenith but much lighter blue at the horizon?)

[roel]

I don't know how large your terrain is, but atmospheric scattering can also provide more sense of scale. Like this:
It depends what you exactly want. You can also get away with a nice (pre-rendered) skybox and some fog.

[Vilem Otte]

I'd say that atmospheric scattering is a must in current game engine. I'd recommend you to google Preetham atmospheric scattering paper, where is really much info on it ... it consists of rayleigh and mie scattering - you need to compute these two and then your atmospheric scattering is complete ... another part is could and its shading ... and thats a bit more of a nightmare than atmospheric scattering :(

[rouncer]

roel said:

You can also get away with a nice (pre-rendered) skybox and some fog.

So you think you would be able to tell the difference if it was just all calculated and stored in a skybox?

I was sorta envisioning some kind of "violent cloud storm" that would be nice.

So the atmospheric scattering builds up the back colour, then you sorta add clouds to this...

[Reedbeta]

Most shipping games have a high-res skybox (1024 in Infamous, for instance), and maybe a couple of animated cloud layers composited in front of that. A few (Brutal Legend) have very complex sky with many layers, particles, etc. The skybox is definitely easier for artists to control than a physically based model, but the physical model is nice for those of us with no art skills, as well as being technically "sweet".

[rouncer]

I spose if you had a *really* good artist, he could go paint some kind of weather effect straight onto the skybox... but maybe id prefer some kind of rendering approach, actually rendering(physically based model) the sky probably could give you better results than most artists could give you. (especially my hand crafted sky, i probably couldnt do it, havent ever studied clouds before)

Ill read more on clouds, at the moment I pretty much have no idea how to go about rendering a cloud... But alphadog gave me a link to some pretty algorythms alright, albiet some arent realtime (but note you could always render and store them in a skybox, so that might come in handy for some real pretty clouds.)

Is definitely something I always overlooked in game production.

im looking at this right now http://www-evasion.i...BC08/clouds.pdf

[Mattias Gustavsson]

You might get some ideas from this presentation: http://www.drewskill...GDC2010_VFX.pdf
Their sky is quite stylized, but I'm sure you could use similar techniques for something more realistic.

If you want to render clouds, take a look at this: http://www.ofb.net/~niniane/clouds/

[roel]

Thanks, that Brutal Legend presentation is an interesting read, I don't understand how I missed it :(