Continuing Sam's investigations on crystal shapes and materials, and 
using KrystalShaper as the primary crystal builder.

This is a crystal of apophyllite. The coloured variety is 
Fluorapophyllite-(K).

I based the material on the one given by Sam in the "Alum" post in 
September last, including Alain's comments. I then added surface normals 
from the crystal experiments by Jaime Vives Piqueres, as also a more 
'cloudy' aspect using a bit of scattering media, and a density block. 
Finally, I added photons. Possibly, the hue should be a tiny bit more 
bluish-green...

The environment makes use of a hdri map and a spotlight. The render 
makes use of a, non-optimal, stochastic setting, which explains the 
grainy aspect. However, I am still experimenting.

-- 
Thomas

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Attachments:
Download 'krystalshaper_apophyllite_004d.jpg' (75 KB)

Preview of image 'krystalshaper_apophyllite_004d.jpg'

Thomas de Groot <tho### [at] degrootorg> wrote:
> Continuing Sam's investigations on crystal shapes and materials, and
> using KrystalShaper as the primary crystal builder.
>
> This is a crystal of apophyllite. The coloured variety is
> Fluorapophyllite-(K).
>
> I based the material on the one given by Sam in the "Alum" post in
> September last, including Alain's comments. I then added surface normals
> from the crystal experiments by Jaime Vives Piqueres, as also a more
> 'cloudy' aspect using a bit of scattering media, and a density block.
> Finally, I added photons. Possibly, the hue should be a tiny bit more
> bluish-green...
>
> The environment makes use of a hdri map and a spotlight. The render
> makes use of a, non-optimal, stochastic setting, which explains the
> grainy aspect. However, I am still experimenting.
>
> --
> Thomas

This looks so promissing! Thanks for sharing!

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Thomas de Groot <tho### [at] degrootorg> wrote:

> The environment makes use of a hdri map and a spotlight. The render
> makes use of a, non-optimal, stochastic setting, which explains the
> grainy aspect. However, I am still experimenting.

I'd like to see a cleaner render - without the really grainy stuff, and a nice
clean, smooth background.  But I like the crystal - it looks pretty cool.   Does
the software export vertice information?
Thinking that maybe any calculation runs can be saved to some sort of include
file.

-BW

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Il 24/10/2021 15:28, Thomas de Groot ha scritto:
 > Continuing Sam's investigations on crystal shapes and materials, and
 > using KrystalShaper as the primary crystal builder.
 >
 > This is a crystal of apophyllite. The coloured variety is
 > Fluorapophyllite-(K).
 >
 > [...]

The crystal is very realistic, and I agree with Bald Eagle, a different 
background could increase this realism.

Another thing: the crystal is vertical and gives a strange feeling to be 
unaffected by the gravity... have you thought of adding a rock or 
something else as a base?


Paolo

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Op 24/10/2021 om 23:04 schreef Bald Eagle:
> Thomas de Groot <tho### [at] degrootorg> wrote:
> 
>> The environment makes use of a hdri map and a spotlight. The render
>> makes use of a, non-optimal, stochastic setting, which explains the
>> grainy aspect. However, I am still experimenting.
> 
> I'd like to see a cleaner render - without the really grainy stuff, and a nice
> clean, smooth background.  But I like the crystal - it looks pretty cool.   Does
> the software export vertice information?

The software exports a set of intersected planes (which are used here) 
/and/ a set of unioned cylinders representing the ribs. Vertice info can 
be derived from those last, obviously. I have not looked seriously at 
that part of the code.

> Thinking that maybe any calculation runs can be saved to some sort of include
> file.

Oh yes indeed. A lot of streamlining can be made on the code. Not sure 
if I want to go all that way though, but I shall post a scene file when 
I have cleaned up the whole mess. For the time being I am content with 
trying to obtain as 'realistic' a crystal as possible.


-- 
Thomas

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Op 24/10/2021 om 15:56 schreef Mr:
> 
> This looks so promissing! Thanks for sharing!
> 
> 
Well, yes. It is a change from granites. ;-) But I have /no/ intentions 
to turn this into a monster macro!

-- 
Thomas

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Op 25/10/2021 om 00:08 schreef Paolo Gibellini:
> The crystal is very realistic, and I agree with Bald Eagle, a different 
> background could increase this realism.
> 
> Another thing: the crystal is vertical and gives a strange feeling to be 
> unaffected by the gravity... have you thought of adding a rock or 
> something else as a base?
> 

Jaime did that indeed (adding a rock) and I probably shall do the same, 
possibly all posed on some dark velvet cloth...

-- 
Thomas

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> The crystal is very realistic, and I agree with Bald Eagle, a different 
> background could increase this realism.
> 
> Another thing: the crystal is vertical and gives a strange feeling to be 
> unaffected by the gravity... have you thought of adding a rock or 
> something else as a base?
> 
> 
> Paolo
> 
I understand the image as a very nice technical demonstration of shaping 
and texturing gems. A base would hide some of the caustics. I think I 
will have a look into this issue. I played a bit with photons too.

Best regards
Michael

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Op 25/10/2021 om 08:47 schreef MichaelJF:
>> The crystal is very realistic, and I agree with Bald Eagle, a 
>> different background could increase this realism.
>>
>> Another thing: the crystal is vertical and gives a strange feeling to 
>> be unaffected by the gravity... have you thought of adding a rock or 
>> something else as a base?
>>
>>
>> Paolo
>>
> I understand the image as a very nice technical demonstration of shaping 
> and texturing gems. A base would hide some of the caustics. I think I 
> will have a look into this issue. I played a bit with photons too.
> 
Correct. My primary purpose was to demonstrate the crystal by itself, 
without the - secondary - scene additions.

It is my understanding that part of the caustics would probably remain 
visible on a supporting rock. Jaime's images show them iirc.

-- 
Thomas

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Thomas de Groot <tho### [at] degrootorg> wrote:
> Continuing Sam's investigations on crystal shapes and materials, and
> using KrystalShaper as the primary crystal builder.
>
> This is a crystal of apophyllite. The coloured variety is
> Fluorapophyllite-(K).
> (...)

Hey Thomas, it looks good!

I agree with Bald Eagle that a cleaner render would be nice, but of course that
would drive up the render time, should you wish to increase the number of
samples. I mean, you're using scattering media + caustics, and we all know how
that goes.

How long did this take to render? The file name says 004d, so I really hope it
wasn't 4 days ':/

I'd like to discover a cheap and realistic way to add internal fractures to
mineral renders. Apophyllite is one of those minerals prone to being found in a
fractured state. I have two ideas in mind, but both are rather expensive: 1)
height fields intersecting not only each other, but also the crystal shape
(which is itself an intersection); or 2) isosurfaces. Both can be very, very
slow. Sometimes I wish media had an ior block.

Is there an online POV-Ray render farm anywhere? :P

Apophyllite is one of those minerals I'd love to find. Since it occurs in basalt
vesicles, one might think it'd be everywhere, but finding any mineral-bearing
cavities is already a challenge...

Sam

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