Material
Tips and Tricks Part 3
by Montree T. (easyyong@hotmail.com) - Smoke3dStudio
3. Tips for reflection and refraction maps
3.1
Perpendicular and parallel The
anisotropic effect produces different kinds of reflection. The
reflection will change more or less depending on the viweing
angle. The least reflection will appear on a suface that is perpendicular
to the
camera and the most reflection appear on surface
that is parallel to the camera. This effect is called the fresnal
effect.
1.You
can see this effect on most of the anisotropic objects ie. damp/wet
road, water surface on swimming pool, polished leather,
some kind of metals and etc.

The reflection is changed in every angle. The bird eyes
angle has less reflection and more reflection at the worm
eyes view (where the camera angle is almost parallel to the wet floor)
2.
Curve/freeform object ie. Cylinder, and sphere and etc.
The least reflection is at the middle of the cylinder which
surface is the area perpendicular to the camera and the more
reflection is on the suface which is parallel to the camera.
You can create this effect by using a fall off map (perpendicular/parallel
or fresnal) over raytrace. Both perpendicular/parallel and fresnal
produce almost similar effects, but I found perpendicular/parallel
to be more apparent.
3.2
Shadow and Light
Falloff "shadow
and light" seems far different from
the real world reflection. I am not sure if there are any theories
about this, but I just use it to accerelate the reflection at the
light area and dim down the reflection in the shaodw areas.
This will create "subdued mood" in your scene. Imagine
the reflection on a black granite floor in a pub. The bright
area will be blow the light and will then disappear
into the shadows.

Shows the parameters and settings of Shadow and light.
A rendering with Shadow and light falling off. The reflection
give a subdued mood.
3.3.
Some examples of complex scene refractions
This
is quite off-topic in that doesn't lend itself to our architecural
tutorials, but we basically need to know how it works so that
we can apply it on our own .
3.3.1
Create water drops on a glass
I will skip mentioning about details on lighting as this is a simple
scene. Let's just look at the wire frame only.
After a few time tests on the materials, I decided
to use raytrace material as the effect is much easier to create
than standard material.
Also, I found the splash map is the more suitable than cellular
as the effect appears clearer. I used blend material for the
glass
model which contains 2 materials ie. galss material and water material
and a splash map for masking.
The rendering
time was about 32 minutes and it quite long for a dual processor.
Glass
material legend
1. Glass material. It seemed to be very easy as I didn't even put
any map on it. Just change the color of diffuse, transparency and
reflection and change the IOR to be
1.5.

2. Water drop material. I just copied the same mateial from the first
slot and changed the IOR to be 1.333 for the water, and copyied the
same masking map (slash map from slot#3) and placed it on spec.level
and Bump.
3. Masking map : splash
This is the floor materail which uses a similar technique to
the blend material.
The image above is very close to the 1st one but uses
only material#2 which is the water. There are bump and specualar
effects except that it has only 1 IOR that is set to 1.33. If you
don't mind about the IOR. The rendering time is quite fast at 3.32
minutes.
3.2
Diamond Someone
had asked me how to draw a diamond. Rendering a diamond is not
as difficult as what you might think. Just use raytrace material
and chnge
the transparency to white, IOR=2.417 and facet, that's all. The
diamond model and its surface is also important that you need to
find a blue print to see how it looks before you draw.

This is roughly how the edge of the diamond looks like.
Put seveal color of lights around the diamond
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