dimanche 11 septembre 2011

CG Clouds research

I love clouds, and make them on computer is a real challenge.
There is many ways to make that in environment generating softwares as Vue, Terragen 2, etc.
In that post I will focus on ways to make it directly in 3ds Max.

I made some simulation tests, and I keep making some on my free time :) The idea is to use only 1 frame of a sim to get static clouds and find the right parameters. The problem: renders are too long.

2/ Using the Damian Nenow technic but instead of scattered planes randomly rotated, I use baked Pflow planes looking at camera and... we have a problem here for moving camera scenes. As planes rotate to look at the camera they intersect each other:

In this test it looks good, but it's only because the camera motion sucks:

The solution? Use spheres with huge falloff, but we lose all the nice alpha maps details we can have with planes:

It pops at the end because I made the render in 2 parts and the 2nd part is with "force 2 sides" checked in the render tab ^^
It looks too diffuse.

The planes orientated to the camera method can be used for stills or simple camera motion:

3/ Dust Devil from Blur Studio looks like the good solution for light, fog, myst render. It doesn't catch the light the way afterburn or FumeFX would do but it looks promising and it's free! (+ render time are faster than the 2 others methods)


Anonyme a dit…

Really cool explanation and tests... Cheers!!

Anonyme a dit…

really cool explanation and tests... cheers!!

Anonyme a dit…

Some really nice tests, I'm trying different approaches as well at the moment. How did you manage to get the scattered spheres so irregularly fluffy?

1k0 a dit…

The fluffy look depends on the textures you use ;)

Anonyme a dit…

Well, I thought so... :) Could you please be a little more specific? Does it have to be a 3D procedural texture or are these regular 2D images? It seems to me, that with 2D images it never looks as if the stuff is inside the sphere. But procedurals always look so regular. Did you use several different textures for your example? Are there only a few big spheres in your example or are these lots of little ones? Is this only one falloff map in the opacity channel with adjusted curve or something more tricky? So many variables... please give me a hint. :)

1k0 a dit…

To be honest, that scene is far away from my memory, so I guess I used 2D cloud textures and put a strong falloff on the sides to avoid penetration artefacts. I may have use different cloud textures to give more randomness. Can't remember about the sphere size, but it should be the same size - or + 20%, if you use too small spheres you will notice them in the render and it could kill the illusion of 3D volumetric.
Do you have an example/WIP of what you're working on?

Anonyme a dit…

It is becoming rather frustrating (and rather too embarassing to show publicly), my WIP is not even close to yours. I just cannot get rid of the sphere shape being still visible. I can hardly imagine how you managed that volumetric look with 2D images on the surface of the spheres. Is it UV-mapped per sphere or on the whole cloud?
I would really like to do this with geometry for the things I want to do with it afterwards, so all the atmospheric options do not work for me. I have also tried Damians approach, but the 2D planes are not that suitable as well at the moment. Please tell me your magic trick. :) Do you perhaps still have the max-file or textures to look at? I am getting quite desperate... :)

Anonyme a dit…

Oh, and sorry, my manners in times of desperate struggle: Thanks a lot for your quick response! :)

1k0 a dit…

Once I'll have time I'll try to get my hands back on these scenes, then I'll be able to give you correct answers ^^

ivan stefan a dit…

I m trying to create same thing with dustdevil. and it is difficult to model with gizmos. i guess u use several different dustdevils in 1 scene.but i cant get that nice noise .do u have sample file?

1k0 a dit…

Hi Ivan,
One message was enough, comments need to be read before they are published ;)
From memory, I only used 1 or 2 spherical gizmos, the shape of the dust devil was made with a big noise size.
Unfortunately I don't have the scene anymore on my computer.



LAB roto slave


L'andalou Maxwell Sound Services