How to create "Crysis clouds"...
Author
Fractal clouds look like crap compared to what they have in Crysis. What algo/technique do they use?
Quote:Original post by e-u-l-o-g-y
http://www.markmark.net/clouds/
Or :
http://niniane.org/clouds/
HellRaiZer
The clouds themselves are doable with regular old particles (that don't move). I've managed to do just fine using 3 channels (XYZ) of Perlin noise range-bounded by a simple bounding box to compute the positions I use -- just that using something like linear interpolation is ugly; sinus interpolation works well enough. For more complex shapes of clouds, you just use multiple boxes to form a single cloud.
The main thing isn't really the cloud itself so much as how you light it. From what I've seen of Warhawk's clouds, I kind of surmise that what they do is a simple raycast to a lightsource testing for particle intersection within the cloud (treating each particle as a sphere) and attenutating the light based on how many intersections were found.
The main thing isn't really the cloud itself so much as how you light it. From what I've seen of Warhawk's clouds, I kind of surmise that what they do is a simple raycast to a lightsource testing for particle intersection within the cloud (treating each particle as a sphere) and attenutating the light based on how many intersections were found.
Quote: Original post by cpiasminc
For more complex shapes of clouds, you just use multiple boxes to form a single cloud.
This is exactly what they do in Flight Simulator 2004 (Realistic and Fast Cloud Rendering), and from the presentation e-u-l-o-g-y posted they seem to use the same method for shading (as in FS2004). So nothing really tricky here. It is more of an artistic work.
Btw, this tracing of spheres and attenuating light would be interesting to investigate further. Maybe on GPU?
IIRC from their videos, smoke seems to be illuminated correctly (i don't know how exact is their method), so i suppose they must use something similar for it. Maybe not for the clouds, but for the smoke. Any ideas on that?
HellRaiZer
PS. Nothing of the above is 100% sure.
I recently implemented some clouds in my engine, mostly prompted by this thread..I think they turned out quite nice.. they are based on rendering batched sprites with some lighitng shaders.. they are real 3d clouds in a the world space.. not faked or on the skydome.. they float some way above the level, like real clouds.
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