POV-Ray : Newsgroups : povray.newusers : Transparent Objects Become Black : Re: Transparent Objects Become Black Server Time
16 Aug 2022 08:52:30 EDT (-0400)
  Re: Transparent Objects Become Black  
From: Kenneth
Date: 17 Nov 2021 16:10:00
Message: <web.61956cb028696f324cef624e6e066e29@news.povray.org>
Thomas de Groot <tho### [at] degrootorg> wrote:
> Kenneth, I have not tested it here, but are the 'voids' really
> necessary? Is it not enough to just add the bubbles to the gel, as both
> have different ior's and do not interact?

Apparently, the visual result is exactly the same either way.

Here is my own "poor man's crystal", ha-- just an intersection of three rotated
boxes. The inclusions are simple shapes. I rendered two versions, with the
inclusions as a UNION with the crystal vs. being DIFFERENCED from it as voids. I
see absolutely no visual change, although I was expecting them to look
completely different. It seems that the ior 'effect' depends only on the
*surfaces* that the camera ray sees, not really on any imagined interior
substance of the inclusions.

I have not yet tested my scene to discover how the different iors affect each
other-- i.e., simple addition vs. multiplication of the iors. That's difficult
to tell, visually. I suspect that it's just addition.

BTW, this 'multiple-ior' effect gave me an idea-- which I am experimenting
with-- about creating what looks like *variable* ior within an object, that
changes along its length or depth, etc. The basic idea is to pre-slice the
object into *many* very thin box sections, each with a slightly increasing ior
value, then re-combine the slices to look like the original solid object. Of
course, I am running into coincident-surface problems with all of those slice
recombinations... but I think that's a temporary problem, until I figure out how
best to re-position them. (Should they be separated by tiny 'air' gaps-- or
should they be slightly embedded into each other?) Anyway, my experiments look
promising so far, if a bit...odd ;-)

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