Mike nous illumina en ce 2008-10-13 13:37 -->
> Actually, I just tried it with photons on and it did not get rid of the
> speckles.  Also, I do not think the speckles are from the egg crate pattern
> since the frequency is too small and since this program does not seem to take
> into account interference of waves, I don't think it would be possible to have
> such a small frequency developing.  The reason I am being such a stickler with
> this is that I plan on using this for visualizing an experiment and we would at
> least try to minimize artifacts as much as possible.
> 
> -Mike
> 
> 
> 
> 
> "Cousin Ricky" <ric### [at] yahoocom> wrote:
>> "Mike" <win### [at] hotmailcom> wrote:
>>>   My problem is that when I try to
>>> merge the two objects I create, I have tried merge and union I always see a
>>> middle boundary in between them.  The indicies of refraction are matched and I
>>> am using fresnel reflection, so I do not see how or why I am seeing this.  If
>>> anyone has any ideas on how to make this artifact go away that would be very
>>> helpful.  I have posted the code I used to make the object below.
>> This looks like a coincident surface problem.  Usually this shows up as
>> speckles, but in your case it appears to have obliterated both surfaces.
>>
>> The quick solution would have been to change the 3.2 to 3.4999 so that the
>> overlap area is only 0.0001--but that didn't eliminate the problem for me; it
>> only made it thinner.
>>
>> But I like Mike Williams's solution better anyway.  The cast spots seem to be
>> from the egg-carton topology, although I can't think of why that would be.  But
>> once you turn on photons, they'll refract into a spotted pattern anyway, so I
>> wouldn't worry about them.
> 
> 
> 
> 
What can explain the speckling is multiple total internal reflections. At one 
pixel, you may have only a few, but the next pixel may need a max_trace_level 
near the maximum of 255.
Have you tried increasing adc_bailout? It limit the number on reflection and 
refractions based on the effective contribution to the colour returned by a ray. 
In some cases, it won't change a thing, in others, it can greatly help, and in 
still other, it may not be acceptable. Only experimentation can tell you if it's 
acceptable in a specific case.

In some cases, adding "all_intersections" can help.

-- 
Alain
-------------------------------------------------
   My wife is such a bad cook, in my house we pray after the meal.
   	Rodney Dangerfield

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