Thomas de Groot <tho### [at] degrootorg> wrote:
>
> I am not yet sure about those 'media voids'... I shall have to think about that.

Yeah, I probably spoke too soon-- such voids would not produce the same visual
effect as your own method of creating voids with actual geometry.
>
> The only media used here
> is an absorbing media which takes care of it all (with the ior too of
> course). I experimented with the scattering media in addition to the
> absorbing one, because Jaime did something like that in his crystal
> experiments.
>
> http://www.ignorancia.org/index.php/galleries/latest-images/crystals-and-mushrooms/
>
> However, I did not find it to work as expected.
>

Also, it occurred to me that any fractures or cleavage planes in a crystal would
need to have some partial reflectivity (if I understand the concept of such
planes). Thin slices of interior media certainly cannot do that. :-(

BTW, thanks for the link to Jaime's crystals; I will take a look at his examples
and code.

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Op 1-11-2021 om 12:26 schreef Kenneth:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>>
>> I am not yet sure about those 'media voids'... I shall have to think about that.
> 
> Yeah, I probably spoke too soon-- such voids would not produce the same visual
> effect as your own method of creating voids with actual geometry.

Correct. I am struggling with the concept however, if I would add a 
separate media to the voids (even tiny ones). The scene file I consulted 
as an example is from Glenn McCarter's Plumbing suite (2003): 
http://www.irtc.org/stills/2003-06-30.html (3rd Place) and he happily 
does mix them, but I am not really sure he is doing things correctly, 
especially now with newer pov versions.

>>
>> The only media used here
>> is an absorbing media which takes care of it all (with the ior too of
>> course). I experimented with the scattering media in addition to the
>> absorbing one, because Jaime did something like that in his crystal
>> experiments.
>>
>> http://www.ignorancia.org/index.php/galleries/latest-images/crystals-and-mushrooms/
>>
>> However, I did not find it to work as expected.
>>
> 
> Also, it occurred to me that any fractures or cleavage planes in a crystal would
> need to have some partial reflectivity (if I understand the concept of such
> planes). Thin slices of interior media certainly cannot do that. :-(
> 
Yes, there is that too. Still, I want to experiment with it to see what 
would happen.

> BTW, thanks for the link to Jaime's crystals; I will take a look at his examples
> and code.
> 
> 
Jaime's work is often a treasure trove indeed.

-- 
Thomas

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Warning! No photons! :-)

After a good three hours render, this is the crystal with 'fluid' 
inclusions added: 15000 little hollow spheres with an ior of 1.0.

Not sure how 'natural' this is looking. I have seen crystals with 
concentrations of 'bubbles' more or less like this. Maybe I have 
exaggerated a bit; maybe there should be less 'bubbles'...

Personally, I like it but I am interested in your verdicts.

-- 
Thomas

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Attachments:
Download 'krystalshaper_apophyllite_006a.jpg' (64 KB)

Preview of image 'krystalshaper_apophyllite_006a.jpg'

hi,

Thomas de Groot <tho### [at] degrootorg> wrote:
> ...
> Personally, I like it but I am interested in your verdicts.

very nice, "like".  :-)  I'd be interested to see a version where the "bubbles"
are confined to a smaller volume within, and also "off-centre", a little.


regards, jr.

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Op 2-11-2021 om 12:29 schreef jr:
> hi,
> 
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> ...
>> Personally, I like it but I am interested in your verdicts.
> 
> very nice, "like".  :-)  I'd be interested to see a version where the "bubbles"
> are confined to a smaller volume within, and also "off-centre", a little.
> 
Smaller volume: yes, that would be interesting
off-centre: ok

-- 
Thomas

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> Thomas de Groot <tho### [at] degrootorg> wrote:
> > ...
> > Personally, I like it but I am interested in your verdicts.

So, to me, it still looks a bit - murky.  Like I'm viewing the render through a
haze or slightly out of focus.

I'm not sure if it's the render settings, the lighting, or the contribution of
the textured ground plane, or what.  I just get the impression that I should be
seeing some crisp(er) edges on the front of the crystal, and instead they are
kind of muddled / blended in with the body of the crystal.

I like the bubbles - I know what you're trying to accomplish there.  Perhaps -
fewer? Slightly more spread out?
This would definitely be a great method for making a realistic ice cube with the
frozen air bubbles inside...

I would be interested in seeing a clean, crisp, clear or opaque version, which
ought to render very quickly, and also - one employing the new granite material!
 :D

This has also got me wanting to see an amethyst, with the clear-to-purple color
gradient.

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Op 02/11/2021 om 21:46 schreef Bald Eagle:
> 
>> Thomas de Groot <tho### [at] degrootorg> wrote:
>>> ...
>>> Personally, I like it but I am interested in your verdicts.
> 
> So, to me, it still looks a bit - murky.  Like I'm viewing the render through a
> haze or slightly out of focus.
> 
> I'm not sure if it's the render settings, the lighting, or the contribution of
> the textured ground plane, or what.  I just get the impression that I should be
> seeing some crisp(er) edges on the front of the crystal, and instead they are
> kind of muddled / blended in with the body of the crystal.
> 
I have no idea. I guess it could be the lighting (area light), but the 
edges /are/ crisp, you can take my word for this.

I shall soon have a demo scene file ready for you to play with.

> I like the bubbles - I know what you're trying to accomplish there.  Perhaps -
> fewer? Slightly more spread out?

Yes, I think there are too many anyway.

> This would definitely be a great method for making a realistic ice cube with the
> frozen air bubbles inside...
> 
Indeed.

> I would be interested in seeing a clean, crisp, clear or opaque version, which
> ought to render very quickly, and also - one employing the new granite material!
>   :D
> 
A /granite/ material? What are you talking about? ;-)

I shall provide that asap. Note that the bubbles will be invisible... :-}

> This has also got me wanting to see an amethyst, with the clear-to-purple color
> gradient.
> 
Indeed. I think I shall leave that to others after I provide the code.

-- 
Thomas

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Latest, less inclusions, and slightly more concentrated and de-centered.

The complete set of files can be found now in the p.b.s-f

I added a quartz crystal to the set.

-- 
Thomas

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Preview of image 'krystalshaper_apophyllite_006b.jpg'

Thomas de Groot <tho### [at] degrootorg> wrote:
> Latest, less inclusions, and slightly more concentrated and de-centered.

It looks decent!

I've got a bunch of ideas, but I need to find the proper motivation to implement
them :/

Only thing I want to suggest at this point is to maybe situate the light_source
&/ sky_sphere so that it casts a highlight off either an outside or inside
surface.

Sam

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Thomas de Groot <tho### [at] degrootorg> wrote:
> Latest, less inclusions, and slightly more concentrated and de-centered.
>
> The complete set of files can be found now in the p.b.s-f
>
> I added a quartz crystal to the set.
>
I like this. AND the previous render with more bubbles. Beautiful.

BTW, I did not realize that an object with ior could have inclusions (other
objects) with *different* ior's-- I thought such constructs would be an example
of 'variable' ior within an object, which cannot be accomplished in POV-ray,
AFAIU. I had a mistaken notion that the camera ray would 'see' the outer object
surface first, which would then set the ior for the entire union-ed CSG. (Kind
of like the way media operates.) But that's not the case! :-) So I've been
experimenting with this multiple-ior CSG trick, which can produce some visually
interesting results. Thanks for the idea.

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