Cloud tunnel (again, Blender can render good volumetric clouds)

(Ace Dragon) #1

http://img101.imageshack.us/my.php?image=0308om2.png
http://gallery.mudpuddle.co.nz/albums/kansas15/0308_G.thumb.png
More proof that with a bit of tweaking, particle billboards and SSS, Blender can be made to render good clouds. In case you don’t know what SSS has done for Blender, in conjunction with particle billboards, good looking volumetric gas effects can be rendered.

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(The_Warder) #2

its very dark cant see much.

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(Smoking_mirror) #3

Of course there is a difference between realistic and naturalistic.

This looks realistic, but would only be naturalistic if you lived in the bowels of hell.

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(Ace Dragon) #4

It looked decently light when looking slightly down at it from my computer monitor.

As for the bowels of hell thing, the image that was supposed to represent actual clouds in the sky was my last cloud test further down the page, I actually went and did some atmospherics here, it was to the point I was no longer trying to do a formation you’d find in Earth’s sky.

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(Meta-Androcto) #5

hey cd, your last one was much better.
this would look better with a blue sky so we can see the clouds clearly.
you are obviously putting a lot of work into this, so why not do a blue sky render,
share a blend, so everyone can work with you on perfecting clouds.
you’ll get much help & positive feedback.
m.a.

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(Ace Dragon) #6

Like I said, I was trying to be more atmospheric in this one, with the settings in place it wouldn’t be that hard to bring back a nice blue sky render.

Blender can render good volumetric clouds, but it takes a lot of work and setup to get right, you’d think all hopes for good volumetric gas materials ended with the failed sky generator project, but then came SSS and hope came alive again.

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(Myke) #7

Actually that looks really good. I’m not sure the clouds would look good with a blue (or rather: a brighter) sky but here they work very well!

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(CoreyAvitar) #8

hey looks good!
Can you show us how you obtained that?
maybe a blend?

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(marky1991) #9

i can barely tell what’s what, im not trying to be too negative, but i definitely agree, it’s too dark and hard to see. On the upside, it would make a nice evil sky.

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(TV Crash) #10

You say that you used SSS?:confused: Would you care to elaborate?

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(Ace Dragon) #11

TV Crash: the SSS panel is in the material settings you need 2.44 or later to use it. And it can be used on planes.

Can you show us how you obtained that?

The texture of the planes
-UVmapped sphere blend texture set to stencil
-Clouds texture set to alpha
The SSS
-Scale set very high (350.000)
-No backscattering
-Fair amount of foward scattering
-Scattering color set to white
The planes
-Parented to a mesh with a particle system with dupiverts
The lights
-Low AO
-Orangish Sun Lamp with ray shadows
NOTE: The reason why the scale must be so high is to prevent ugly artifacts.

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(kroni) #12

hmm looks ok
couple of questions:

  • how long did it take to setup and what was the render time ?
  • could u make a simple scene (lets say a glass box with some gathering clouds inside) with this technique ? (and maybe post it to my Doodles topic with a .blend ?)

im asking, because my attempts at creating clouds ended up with painting them on the render which is pretty fast and reliable :wink:

  • Kroni
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(Ace Dragon) #13

This took about a day to render, though it’s with cloud covering the entire scene which is often not needed.

These can be raytraced, but are held back by the fact a reflected or refracted ray goes through only 10 z-transparent planes per pixel in Blender before getting colorful squares from my experience. If the raytracer can be optimized for far depth it would be practical to raise the maximum ray depth way up or simply not count z-transparent meshes against a refracted or reflected ray. Now if the ray did not have to go through many planes before they become opaque or the number of planes is minimized then it could be practical for such a thing. Do note really lowering the number of planes means you’ll make it more obvious the clouds are planes using SSS. I’m not sure if ray shadows do the same depth thing, but with transparent and soft shadows it doesn’t make much difference.

Also, use a decent plane size too, really small planes do not fare well, use a medium to semi-large plane, but not too large.

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(free_ality) #14

This took about a day to render, though it’s with cloud covering the entire scene which is often not needed.

That’s completely ludicrous, I’ll just paint a cloud texture instead. Plus(no offense) it doesnt look that fantastic.

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(kernond) #15

You should definitely study these resources, especially the "5-minute video"and the “full paper” links. It’s very informative and demonstrates that you really don’t need to wait for volumetrics. I imagine that volumetrics will be very slow in rendering due to the complexities, much like fluids. So, volumetrics won’t be the answer for every need. Especially when time is a factor. The clouds demonstrated in that video are pretty darn good and, the video and other resources provide great details on how to achieve the same effects. I wish I had time to really look into it myself. Hopefully, someone will spend some time with it and produce some really good proofs.

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(Ace Dragon) #16

Let’s go farther then that, why do 3D programs even exist if we can just paint our pics. Heck let’s all go back to an easel and paintbrush. You can always just switch to non-digital art (get an easel, a canvas, and a selection of paints, pastels, and colored pencils), that way you have no rendering times.

Hey if you want to complain about cool stuff done in Blender Internal that not many have thought of before then…

I’m rendering a third clouds image to see how it interacts with solid objects, the clouds will be white with a blue sky though it won’t be a random collection of shapes.

Kernond: To make the situation described by the abstract work and use dupliverts you’ll need to make the dupliverts real objects and then use a python script to set vertex color based on light position. This could be a fast option, but you’ll probably need python experience to set the vertex colors. After that all you need is to set Vcol light in the material options. The making the dupliverts real wouldn’t be needed if the python API had access to set different vertex coloring per duplivert.

The main drawback would likely be clouds casting shadows on clouds and vertex color resolution.

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(kernond) #17

“Don’t knock it 'til you try it.” I didn’t say it would be an instant solution.

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(Ace Dragon) #18

But unless you want the hassle to set the vertex colors yourself you’ll need python to find the position of the lights and have the vertex colors set accordingly, I don’t know any python.

I could end up enlarging the planes considerably and make clouds with much less planes, but then they look a lot more like cartoon clouds in the way that the edges look round with a few bumps, I’m after realistic clouds, not a cartoon (which you can already tell).

The possibilities will only increase with Jahka’s particles and the billboard option that comes with it, assuming his billboards can have SSS used on it, then it’ll only increase the ability of using a sphere blend and SSS for the appearence of volumetric clouds.

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(LazyCoder) #19

They may look like volumetric clouds by themselves, but what does it look like if you have something go flying through there? You’ll see the halos intersecting with the mesh.

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(Meta-Androcto) #20

1 day to render, for background clouds.
ground breaking work you’ve got there.
buy a digital camera.
your quick to demand this & that from everyone else, yet refuse to share your work.
you stink.
Edit’ I take back my words, you only smell a little!
thanks for the blend!
m.a.

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