Le 08/08/2011 19:39, Alain a écrit :
> Le 2011/08/07 22:02, kiwon a écrit :
>> 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

I would cheat further: using the object pattern, assuming you have the
collection of wet spots (as particle, they might be promoted to sphere)
in a union, it's a simple matter of providing a wet and a dry look for
each object.

Real liquid part must be coded as usual, but it is only them which need
an actual ior. The other solids can remain as previously, just changing
the wet/dry look based on the object pattern and its inside tests.



-- 
Software is like dirt - it costs time and money to change it and move it
around.

Just because you can't see it, it doesn't weigh anything,
and you can't drill a hole in it and stick a rivet into it doesn't mean
it's free.

Post a reply to this message