Solar panels
are, usually, made out of gallium arsenide. This compound presents
itself in the form of large cristalized formation that reflect
light in defferent ways, depending on the angle of incidence
of light itself. To create such an effect in Cinema4D we have
to create a compound shader too. We must combine several discreet
ways to react to light coming from different angles into one
single material. The new Layer shader is a
natural for what we need. Unfortunately it only exists in release
8.3.
Inside
the Color channel create a new Layer shader.
Inside it place a Colorizer shader (14) and
choose the shades of blue that you want for the solar panel.
Inside the
Colorizer place a Noise shader
and choose a noise type of Voronoi with the
following parameters:
It is very
important that the Space is set to UV(2D)
to allow us to easily scale the material once it is applied
to an object.
I placed
a HSL shader (13) on top of the Colorizer
so that I could easily control the color in a more general way
but this is not required.
Create a
new Folder (9) and inside it place a Noise
shader with the following parameters:
On top of
it place a Transform (12)shader so that we
can control the angle of the streaks. I set it to 20 but any
other angle will be fine.
On top of the Transform shader create a Colorizer
shader (11) and place inside it a copy of the first Noise
shader you created (lets call it, from now on, the Voronoi
Noise). The Colorize shader should have this parameters:
The Colorizer
should be set to Multiply. This way it will produce a black
image with only a few cells filled with the streaks created
by the Noise shader inside the folder. Now
set the folder tranfer mode to Screen. This will combine it
with the color defined bellow.
You now
need to recreate the folder you just created, two more times
(1 and 5).
The Noise
shader that creates the streaks can have its parameters slightly
changed.
The Colorizer that affects the Voronoi
Noise must be set to different values in order to change
different voronoi polygons to black and white. I set the Colorizers
(2 and 6) to these values:
Also change
the Transform (3 and 7) angle value to different
values to vary the direction of the streaks.
Now, to
create changes on the specular highlight according to the angle
of light, lets create a Layer shader in the Specular Color channel.
Set Colorizers
3, 6, 9 and 12 to the following parameters:
Colorizer
(3) |
Colorizer
(6) |
Colorizer
(9) |
Colorizer
(12) |
Inside
each Colorizer place a copy of the Voronoi
Noise.
On top of each Colorizer place a Fresnel
shader and set their parameters to the following values:
Fresnel
(2) |
Fresnel
(5) |
Fresnel
(8) |
Fresnel
(11) |
Set the
transfer mode of each Fresnel to Multiply.
Set the transfer mode of each folder to Add.
The Fresnel masks will create a different Voronoi
Noise for different angles of incidence.
Set the
Specular Color channel to the following:
This way
the result of the combined Layer shaders can
be easily tinted.
Finaly,
set the Specular channel to something like
this:
It just
needs to be wide enough to spread the effect and be high enough
to be visible.
I also added an image to the Environment channel
but that is optional, of course.
Have fun
playing with variations of this setup :-)