Although
Combustion is mostly used for explosion
effects, you can also use it to
create smoke and clouds. This tutorial
teaches you how to create the cloud
shown above in a matter of minutes.
From
the Create menu choose Helpers,
and select the Sphere gizmo
from the Atmospherics rollout.
Create a gizmo by dragging
your cursor in your Perspective
viewport. Check "Hemisphere".
In my case the gizmo had a
radius of 100 units. In your
Front viewport shift-drag
a copy of this gizmo along
the y-axis. Now you have two
gizmos stacked on top of each
other. In my case, the second
gizmo was positioned 5 units
lower then the original one.
Now you have to scale your
gizmos first, to let them
take the basic shape of a
cloud. For the upper gizmo,
I scaled the Z-axis by 70%.
The second gizmo was scaled
by 70% in both X-axis and
Y-axis, while the Z-axis was
scaled to 20% (Figure 1).
Figure
1 - The Hemisphere gizmos
Now
you've set up your gizmos,
it's time to add some atmospherics.
From the Render menu, click
Environment and add a Combustion
in the Atmospherics rollout.
Assign the upper gizmo to
this Combustion. Since you've
squashed your gizmo a bit,
it's wise to increase the
Stretch value, to obtain properly
shaped clouds. Leave the Phase
and Wind settings as they
are. You might want to mess
with them later, if you're
going to animate your cloud,
but that's beyond the scope
of this tutorial. As the other
options of the Combustion
rollout are pretty self-explaining,
I won't go into the details
here. Just adjust the setting
to get something similar to
this (Figure 2):
Figure
2 - First Combustion rollout
Add
another Combustion and
pick the lower gizmo.
This Combustion will
represent the shadows
of your cloud. Therefore
choose darker colors.
Adjust the other settings
to resemble the values
in the picture below
(Figure 3).
Now
press the render button.
Remember that combustion
only works in non-orthogonal
viewports, such as the
Perspective viewport
and any Camera viewports.
Now the result doesn't
look good, does it?
That's because the two
Combustions are ordered
incorrectly. Choose
the lower one, and press
"Move Up"
(Figure 4). Now render
again. That looks better!
Figure
4 - Combustion order
Figure
3 - Second Combustion rollout
Now
it's up to you to make your own
unique clouds. Mess with the Colors,
Density, gizmo sizes and Seed value
of the gizmos to obtain the results
you want. Beware though: Combustion
was originally intended for fiery
effects, and this causes them to
"glow" a bit. Therefore
Combustion won't work well for 'clouds
at night' and dark thunderclouds.
Hopefully
this simple tutorial was useful
to you. If you have any comments
or suggestions, mail
me!
