In search of a perfect Storm Cloud

I have always loved clouds. They form in a seemingly infinite number of shapes and even colors depending on time of day and weather patterns. All of which is highly technical and not even remotely interesting to me. I just like looking at them.

For years I have wanted to model clouds, but it always seemed a bigger hassle than it was actually worth. The arrival of volumetric materials peeked my interest again, but boy howdy all the options seemed more confusing than going outside and trying to actually create a cloud. So I shelved the idea once more.

Then I saw a cool cloud tutorial on BlenderCookie, that featured a Cloud Generator add-on. Well yippee me, that looks easy. So of course on my last project I made some clouds. Since the clouds weren’t the main focus of my project, I just used the default settings of the add-on and went with what they produced. Which was pretty good. But after I finished the project, I found myself wanting to create clouds, cool clouds, … STORM CLOUDS!

Storm clouds are the coolest, they have depth and ranges of colors and look all cranky and well, I wanted to make some. 😛

Realizing that this would take a better understanding of volumetric materials, I did a little research and found some info on the various settings and then pulled out my favorite “pointy poke it stick” and proceeded to start poking around to see what I could come up with.

First thing I decided that I wanted to know was actually kind of silly. The BlenderCookie tutorial showed cubes as the cloud base object. Jonathan stacked cubes this way and that and ended up with a nice cloud bank. And that is the method I used on my last project, but honestly, cubes just don’t feel cloud-like to me.

So I made a more cloud-like looking mesh to start my experiments on. Okay, so it started out as a cube as well, but some subdivision and a bit of pushing and pulling of the vertices gave me a more cloud-like mesh to play with.

So, yeah, silly, but it did let me know that the base mesh did not have to be just the default cube.

Okay before you start any testing, you need a control image and or settings. So of course I set one up, I will be using the same cloud mesh, a sun lamp set to mountains (sky and atmosphere) and default settings. Nothing fancy. (I’m not good at fancy 😛 ) I decided to use the Cloud Generator to base my tests on for the simple reason that most everything gets set up for you. From there I could poke at settings to see what, if anything, they did.

Control Image

Using just a default cube with the Cloud Generator set to Cumulus>No Smoothing>No Particles and default material settings, I was rewarded with this image. Nice basic fluffy white cloud. Not bad, but not a storm cloud.

Experiment #1

Same settings, just used fancy new cloud shape I made. I like it. Looks a little more cloud-like. I will use this mesh for the remainder of my tests.

Experiment #2

Time to start poking settings to see what happens. First up.

  • Density 1.00
  • Density Scale 1.00
  • Shading Panel
    • Scattering 1.5
    • Asymetry 0.5
    • Emission (light grey) 2.0
    • Reflection (white) 1.00
  • Lighting Panel
    • Shaded +Multiple Scattering
    • Resolution 100
    • Spread 1.5
    • Scattering Intensity 1.0

And what did I get…

A big BLACK blob. Took me a little bit to locate the problem. In fact Experiment #3 resulted in a big White blob. And the problem was DENSITY, you must and I repeat must have density set to less than 1.0 and the closer to 0.0 the better to get clouds.

Okay first lesson learned, density of 1.0 or higher makes big blocks no matter what your base mesh looks like.

Experiment #4 & #5

No more big blobs, but now my clouds have pink edges. Which confused me for quite a while. I hadn’t set anything to pink. Finally it dawned on me to look in the Texture settings. Yep there the pink was.

  • Density 0.0
  • Density Scale 1.8
  • Lighting Panel
    • Shaded
    • Resolution 100
    • External Shadows

Experiment #6

After getting rid of the pink in the textures, I decided to play with colors a bit. Amazing the difference changing colors can make.

  • Density 0.0
  • Density Scale 1.8
  • Lighting Panel
    • Shaded
    • Resolution 100
    • External Shadows
  • Shading Panel
    • Scattering 1.5
    • Asymetry 0.5
    • Transmission set to dark grey color
    • Emission (white) 2.0
    • Reflection (white) 1.00

Well now that is an improvement. It looks very dark and stormy. But maybe a little too dark.

Experiment #7

This one I ended up liking a lot. It has great character, it looks stormy but lit up a little. Very cool.

  • Density 0.0
  • Density Scale .8
  • Shading
    • Scattering 2.0
    • Asymetry 0.5
    • Transmission Color (0.152, 0.152, 0.152)
    • Emission (light orange) 1.0
    • Reflection (white) 5.00

Very, very cool. So what have I learned so far.

  • Density must be less than 1.0 (0.0 is best for clouds).
  • Higher Density Scale gives thicker clouds, lower gives wispier. I ended up liking 0.8.
  • Color plays a big part in how the cloud looks. Even just slight changes in color makes the ridges and bumps in the cloud have more detail and depth.

I did actually do quite a few more tests that I won’t bore you with. And after hours of playing, discovered a whole set of settings that I hadn’t known about. Silly me, at the bottom of the Texture panel there were settings for the point density. So I did play with them a bit. But I think some more poking is in order as I didn’t really understand them as much as I would have liked.

But I will share some of the cooler clouds that I ended up rendering. 🙂

Fun stuff to say the least. I think I am going wander off and do some testing of the materials from Colin’s book. by now 🙂


One response to “In search of a perfect Storm Cloud

  • nrk

    Looking good, here are some storm clouds I made a while back:

    I highly recommend my tutorial here:

    There are also a couple other under my name that hopefully will help you out.

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