| Author |
Colin Litster |
| Hyperlink |
http://www.cogfilms.com/CQTs-5.html |
| Category |
Effects |
| Title |
Cloud Creation |
TUTORIAL AS QUOTED FROM SOURCE

OK creating clouds in Blender is not easy so do not expect volumetric 3D
particle simulation solutions in this quick tutorial. What I will give are some
of the solutions that I have found that give reasonable cloudlike effects in
blender. In this Cog's Quick tutorial I'm not supplying a blend file to start
you off. It's a good idea to try to create your own cloud based on some of the
settings shown. In this way you can experiment and create your own unique
clouds. However, I do give a final blend file that you can view and explore.
Pre Requisites
You should have an understanding of Blender particles and how to setup a halo
material. You should also know how to add textures to your halo material. If you
don't know these basic techniques please refer to the excellent documentation available from the blender.org site. All the
techniques explained here can be applied to older versions of Blender but the
settings images are from the latest Blender v2.4.
The Technique used
In previous tutorials, specifically Creating Nebula & star-clusters in Blender and Creating Dense Smoke in Blender, I highlighted ways to create
volumetric mists and smoke. I did this by playing with contrast and brightness
settings, of a cloud texture applied as a halotex on a particle system, and
painting the particle system with lights. Essentially the same technique can be
used to create clouds. Of course the level of realism is questionable but by
cheating (the 3D artists most useful tool) it's possible to conjure up some very
atmospheric cloud like images that can be used as backgrounds for other
creations.

As mentioned earlier I'm not giving a start blend file. Just follow the
simple settings given and you should end up with a cloud similar to that shown
above.
Create a simple plain particle emitter
- Start a new blender scene and delete the cube, or any other mesh.
- With the cursor at the X,Y,Z location 0 create a plain mesh in the top
viewport.
- Subdivide it a few times. W, subdivide (Although Blender v2.4 now allows
one to emit particles from faces I want the technique to be backward
compatible. Therefore to give enough particles for our cloud we need quite a
few vertices)

Move the Camera to the following location.

Create a particle emitter from the plain mesh with the following settings.

NOTE:- Both Verts and Faces are selected in this image. If you are
using Blender v2.37, or prior, particles will only emit from the
vertices.
There is nothing very special about these settings apart from the
fact that the Normal and Random are quite low. This ensures that
the cloud produced will be contained in a compact area of the render and not
scattered all over the field of view.
In order to create a dense cloud-like look, to this particle system, its
necessary to apply a halo texture with the following settings.


The important settings here are the fact that the halo settings include,
HaloTex, (allowing a texture to be applied to the halo, and
Shaded (that allow the halo to be illuminated or shaded with
light and shadow). Also of note is the Add setting which is
quite low. If its set much higher the highlight areas of the cloud will be
bleached out with no detail. However, this and other settings can be manipulated
to give some variations so experiment.
As you can see a texture has been added. This is the ubiquitous cloud
texture which is quite appropriate. Apply the following settings.


The important settings here are the Bright and
Contr(ast) settings that increase the contrast ratio to ensure
that the cloud appears as dense as possible. The NoiseSize and
NoiseDepth are also set quite high. However, depending on how
you set your camera, and size of emitter, this may need adjusting to stop the
cloud pattern repeating and spoiling the effect. You can also play with the
Size setting of the Mapto tab in the material
setting. Fractions produce larger sizes. EXPERIMENT!
If you do a test render now you'll probably get a very dark cloud depending
on where your default lights are set. Before we add the lights lets sculpt the
cloud a little to stop it looking like a rectangular box. Edit the plain mesh to
remove some of the vertices.

You can remove any shape you want although be careful not to leave too many
unconnected vertices or the cloud will be rather sparse.
Time to add some lights to paint the cloud. The scene uses 2 light sources.
A Spotlight, representing the sun direction, and a lamp, adding fill light.
Later other lights will be added to create further depth and colour.

The positions of the 2 lamps and there settings are as follows:-
Lamp Light


Colour can be played with as can the Energy of the light.
Spot light



With my test I had to move to frame 18 to do a test render that looks like
this:-

Not bad but it still looks a little too block like. Time to add the magic.
Move your camera much closer to the cloud. If necessary right inside the
cloud to one of those vertex clear areas that you removed earlier.
Another test render may produce something like this:-

Quite dramatic and usable as a backdrop for your spectacular model that
you've been working on. But it doesn't stop there. We can add further lights to
paint individual parts of our cloud to make it just the way we want.
On a particularly dark part of your cloud place a new Lamp
and set it to Sphere.

The important settings here are the Dist, that should be
set quite small, and the Energy that needs to be set quite
high. Both these need experimentation but the idea is that the light will only
illuminate within the sphere.
You can use this to add a Sun like light
within the cloud (It makes it look as though strong sunlight is penetrating
through the cloud with a nice defuse glow). Its also good for adding drama to
your cloud such as lightning glows which can be animated to travel through the
cloud at speed.
IMPORTANT NOTE: If you want to animate
objects like lightning, or planes, or spaceships, you must freeze your particle
system with the TIME object IPO. You can find out about that in
my Creating Nebula & star-clusters in Blender tutorial.
Creating any particle system may be slow to render. Therefore I often create
images of clouds and sky separately then map them onto a part tube, as a kind of
diorama, in my scene.

Here I have mapped the produced sky image to a part tube or a curved plane.
I've added a blend texture to alpha out the base of the diorama to help match it
into any scene.

You can also take the images produced and modify them in a paint package to
add more contrast or other image manipulation before applying them to such a
diorama.

There are endless possibilities with this technique and bold experimentation
is the key. So to help you I include the blendfile that produced the above
image.