A solution for procedural cloud volumes

[profbetis]

Hey Octane users, I did some experiments today in an attempt to render procedural clouds in Octane. Some of you may remember me from another post of mine awhile ago experimenting with volumetrics (http://render.otoy.com/forum/viewtopic.php?t=26161). I have been contacted about those experiments since then, but unfortunately the dev team had to change the program that let a more important issue worked that led to a fundamental change in specular materials meaning that solution was no long possible.

Today I have found a solution. It's not very fast or efficient, but it does work, is animatable, and fully procedural.


It works at different daylight settings.


It can be made to look like overcast.


Beautiful shadows.


Very dynamic!


Here's a view from the top


The secret? Lots of slices. With clay mode turned on, you can see the edges and shadowing, but with the right material properties it practically disappears.


Here's a video of the clouds in animation (http://youtu.be/-0NtjN80i2g)

The step-by-step for setup is
1. Make a very large plane (to the extent that you want your sky to go). Make sure its geometry is as simple as possible (should be 2 triangles / 1 poly )
2. Stack/instance the plane upwards in small increments. The spacing is essentially your 3D resolution for the clouds. If they're spaced out too much you will see the difference in the layers too much. Too little and your clouds won't be able to be very tall. I've found that 15-25 layers is a good amount of layers. Above 25 and it will start bogging down the GPU with all the light bounces through layers with an opacity map.
3. Make a new Diffuse material and apply it to the stack. This next picture will show you how to set up your material. I set mine up in 3DS Max, but the settings will work with any version of Octane.

[Lewis]

Very cool tutorial, thank you, it works smilar in LightWave also .

Just to ask how much actual space (in cm ?) you used for slices model in your test renders ?

Thanks

[profbetis]

my scales were not realistic, so if I said 25cm I feel like it's kind of an arbitrary number and that it really depends on the scene. Perhaps a good rule of thumb is that from your render camera, the width between the layers in your viewport should only be a few pixels.

[Lewis]

my scales were not realistic, so if I said 25cm I feel like it's kind of an arbitrary number and that it really depends on the scene. Perhaps a good rule of thumb is that from your render camera, the width between the layers in your viewport should only be a few pixels.

Yeah, i was testing in render and scaling 25cma and 10cm and i was still seeing slices a bit too much than i would like to but OK i can tweak per scene to get best result

thanks

[oguzbir]

Thanks for the great solution tip.

I made a quick test scene. It's a bit hard to grasp how it works.

Thanks again.

[Phantom107]

Excellent concept

[profbetis]

The noise function is plugged into the opacity, so dark values will be transparent while white values allow the material to appear.

Each slice is a 2 dimensional view of the noise function. By offsetting it slightly, and having a new slice retrieves the same function but at a slightly different Z value, thus progressing in the Z-dimension, which is volumetric.

[Lewis]

Here is my simple Octane clouds tirck test animation
https://www.dropbox.com/s/dto2hyzif2ulk ... 1.rar?dl=0

[profbetis]

Nice! The difference in your layers looks a little high and they look more like separate cloud layers than part of the same cloud. You should either lower your spacing and up your layer count, or have a large Y scale in your noise. Great use of animation though!!

[p3taoctane]

very cool man