Creating cool layers of fog
by Vincent Stoessel

Download the blend file

This tutorials shows how you can create layers of
fog. My "Working with Mist" tutorial showed you how to
manipulate general atmostsperic mist in Blender. But what if
you want to place fog in a specific place? Fog planes or
layers are the answer. When I used Bryce2, I often used
the build-in fog, water ground planes all the time. This
is my way of emulating that cool feature in Blender.
Just for fun , here is one of my old Bryce 2 images.
Notice the fog layer close to the ground.

Below is my Blender intreptation of the same scene.

I'm not going into how I made the models, that's a
tutorial on modelling that I'm also working on. Look out for it.
In any scene it helps to have a plan. Usually you will have
a clear image in your head, but think about mood and enviroment
as well. When I think of fog I think of ancient days and old
temples. Days of Conan and Thor. You might be thinking something
different of course. OK. Fog is ouside right? So this scene
will be outside. If this is outside, is it day or is it
night? In this scene I chose day. I also I choose a land
scene over water scene.

I used stucci and mable as textures for the temple
and a jpeg of dry mud for the floor. Planes are very good
for water, ground and mist. So hit the space bar and
Add->Mesh->Plane. It is best to do this from the top view
(Num Pad 7). Hit the tab button to get out of edit mode.
Press "s" key in order to scale the plane. Stretch it wide
enough to enclose the scene's subject. My new plane is shown
below in highlighted in blue below.

Add a new material for the fog plane. By default you'll
get a gray material with no texture. Hurry over to the
texture buttons and add a new texture. You often have to back and forth
between the materials buttons and the textures to get things looking
way that you want. Below is are the teture settings I used.
A simple cloud texture set to hard noise for more contrast.

Let me spend a little time talking about the material
settings that I used below. If you look to the right
you will see 3 selected buttons. Hard, Alpha, and Emit.
these are part of the 9 output mapping buttons. These buttons
take prior texture data and effects parts of the material.
Such as Color, Normals(bump map), Specular color,
Mirror color (Cmir), Reflection, Specularity value,
Hard value, Alpha and Emit value. I wanted the cloud texture to
effect Hard, Alpha and Emit values. I also gave the cloud a
light blue color. Notice that I selected the Ztransp. That
allows a material to become transparent. The amount of tranparency
is controlled by the Alpha slider left of the center.
I set the Alpha to 0.493. I also made the materiel shadeless,
which makes it insesitive to light or shadow. That's OK,
this material is "emitting" it's own light when I selected
the Emit button in the output mapping.

Okay this is what we have so far.
Notice that now have a layer of fog halfway up the temple's
columns. At this point it would be very easy to tweak this
material to look more like water. Play around with it.

But what about the horizon?
There's no fog there. Now we emplo9 techniques from
my "Working with mists" tutorial to make a linear
fog toward the horizon. Here are my world settings.

Here is the cloud texture for the world settings.

Voila!
This is the result!
I actually like this a lot better than the old
Bryce image. Bryce is very easy to use and has tons
of procedular textures but Blender is
a lot more precise and powerful and the texture will come
in time. Send your comments to me,
Vinny
Thanks