Graphics Programs Reference
In-Depth Information
What we have thus far is a map that defines how intense the roughness of the
surface in each point will be. But there's is a problem: The clouds are as bright as or
even brighter than the Andes and the Himalayas, which means the render process
will distort them quite a lot. Since we know that the intensity of the roughness
on the clouds must be less, let's perform another step to get the map corrected
accordingly.
14. Let's select the left thumbnail of the clouds layer (color channel of the layer), then
go to the main window and open the color levels using the
Levels
tool by going to
Colors
→
Levels...
. In the
Output Levels
part of the dialog box, let's change the
value
255
(on the right-hand side) to
66
and then click on
OK
.
Now we have a map that clearly gives a stronger value to the highest mounts on
earth than to the clouds, which is exactly what we needed.
15. Finally, we just need to change the image mode to RGB (
Image → Mode → RGB
)
and save it as
EarthBumpMap.jpg
in the
tex
folder of the project.
Noice that we are mixing the bump maps of the clouds and the mountains. The reason for
this is that working with separate bump maps will get us into a very tricky situaion when
working inside Blender; definitely, working with a single bump map is way easier than trying
to mix two or more. Now we can close Gimp, since we will work exclusively within Blender
from now on.
Objective Complete - Mini Debriefing
This part of the project was just a preparaion of the textures. We must create these new
textures for three reasons:
F
To get the clouds' texture having a proper alpha channel; this will save us trouble
when working with it in Blender.
F
To c To in t ro l t h e s p e c m a p p ro p e r l y, i in t h e r e g i To in s w h e r e t h e re a re c l To u d s , a s t h e
clouds must not have specular relecion.
F
To create a single, unified bump map for the whole planet. This will save us lots of
trouble when controlling the Normal channel of the material in Blender.
Noice that we are using the term "bump map" to refer to a texture that will
be used to control the "normal" channel of the material. The reason to not call
it "normal map" is because a normal map is a special kind of texture that isn't
coded in grayscale, like our current texture.
