Realistic water with POV-Ray - pigment and finish
This part introduces the different aspects of POV-Ray's pigment and finish statements that are important for water. For the other parts of the tutorial go to the tutorial starting page.
Most important for the appearance of the water are the surface
texture's pigment and finish properties. Together with normal
they form the texture which describes the properties
of the actual surface of an object. The pigment specifies the surface
color while the finish describes how the surface interacts with lights.
pigment
With the pigment you define the surface color. This can be a plain color or a
use an arbitrarily complicated pattern with different colors.
Here we only use a plain color.
In the introduction, i used
color rgbf <1, 1, 1, 1> which is completely transparent.
Changing the filter or transmit
value makes the surface influence the rays, therefore things under water appear in a
different color.
With transmit you can change the non-filtering
transparency of the water. This means things below get darker, but the color itself has
no influence:
color rgbt <0.2, 0.7, 0.3, 0.5>
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With filter on the other hand the surface filters
the light going through:
color rgbf <0.2, 0.7, 0.3, 0.5>
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In general, a completely transparent pigment should be most realistic. Even if the water contains particles and therefore is not completely clear, the surface itself does not attenuate the light. How to influence influence the rays below the actual surface is described in the interior section.
finish
I will now describe the basic finish components that are relevant for water. Reflection is described in detail in a separate section.
In the last samples, ambient and
diffuse finish components are 0. Note that
changing these values only has effect if the filter or transmit value of the pigment is
different from 1, if it is not, the surface is completely transparent.
Increasing the ambient finish now colors the whole surface with the
color the pigment describes. This is usually not of much use for water.
ambient 0.2
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With diffuse only the parts exposed to the light source are
colored. This is a possibility to make the water look a bit muddy without using
scattering media.
diffuse 0.3
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Finally you can also add specular highlights to the surface. There are two different
models for doing this in POV-Ray, phong and
specular, here only specular
is described.
A secondary parameter, roughness influences the size of
the highlights.
| no highlights | specular 0.8, roughness 0.003 | specular 0.8, roughness 0.03 |
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These are the general finish parameters that can be useful for water. Still missing is of course reflection which is described in the following part.
