stbenge nous illumina en ce 2008-10-31 15:25 -->
> feestje wrote:
>> hi all,
>>
>> I want to make an animation about the so-called "mirage effect" on a 
>> heated
>> surface with a sphere present. (what is the mirage effect:
>> http://www.physlink.com/Education/askExperts/ae428.cfm)
>>
>> Basicly the effect is created by a difference in refractive indix of a 
>> hot and a
>> cold medium (water). Is it possible in PORAY to create a location 
>> dependant
>> refractive index?
>>
>> Regards, Ruud
> 
> You cannot give an object a variable index of refraction, sorry. But you 
> *can* stack many transparent objects onto each other, each having a 
> different ior. It might work for the mirage effect. The render times 
> using this method are slooow, even on faster computers.
> 
> Or you could try modeling a microsphere atmosphere, but this would 
> render even more slowly, I'm pretty sure.
> 
> Sam

You may not need many stacked objects. Just one or two thin boxes, or strongly 
flattened spheres or cylinders, with a clever normal may be enough. Just 
remember to keep the ior close to 1.
Start with 1. Do some test renders altering the ior and normal. Then, if needed, 
add a second one. Tewak only that added object to adjust as needed. The second 
object should have an ior closer to 1 than the first.

-- 
Alain
-------------------------------------------------
'hAS ANYONE SEEN MY cAPSLOCK KEY?'

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