> Christian Froeschlin<chr### [at] chrfrde>  wrote:
>> kiwon wrote:
>>
>>> This paper says that they used POV-Ray for rendering, but not so much in detail.
>>> How can I use POV-Ray to render these kinds of materials? Would you please give
>>> me some idea or tip? :)
>>
>> The paper seems to be mostly about simulating the behavior of the
>> fluid, so I think they get some complex water geometry out which they
>> can then render as water in addition to the object (also the object
>> mesh is probably deformed by their algorithm as it soaks).
>
> The simulation is not matter for me, because it's my major research area. I'm
> quite familiar to computational fluid dynamics and fluid simulation in computer
> graphics field.
>
>> It may be quite difficult to get decent results. Some things you
>> can do is make those parts of the object that are wet darker and
>> with more reflection, and add some water geometry such as droplets
>> with trace function.
>
> I'm wondering how I can make POV-Ray to recognize such partially darker and more
> reflective regions. Using texture? (manually generated one using saturation or
> density data coming from the simulation result) media? or other way?
>
> --
> Kiwon Um
>
>

You can use layered textures.

You start with your base texture.
You place another, mostly transparent, texture over it. Dry areas are 
totaly transparent, with a non-reflective finish. If you have specular 
or phong highlights, make those broad and low intensity.
Wet areas use a filtering pigment and a finish having some variable 
reflection: reflection{0.1, 1 fresnel}. Add conserve_energy to the 
finish. This part should have moderate to strong specular or phong 
highlights that are relatively tight.
Add interior{ior 1.33} to your object as it's wet with water. You need 
an ior for the fresnel computation.

If it's suposed to be "wet" from some other kind of liquid, use the ior 
for that liquid. The minimum reflection could also be adjusted as needed.


Alain

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