POV-Ray : Newsgroups : povray.binaries.images : Granite_21 - the final macro : Re: Granite_21 - the final macro Server Time
18 Oct 2021 22:56:13 EDT (-0400)
  Re: Granite_21 - the final macro  
From: Thomas de Groot
Date: 14 Sep 2021 02:54:50
Message: <6140473a$1@news.povray.org>
Op 14/09/2021 om 01:14 schreef Samuel B.:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> Op 10-9-2021 om 22:36 schreef Samuel B.:
>>> Oh, that reminds me. I know your specialty is more on the geological side of
>>> things, but a great tool has just become available for free: KrystalShaper (
>>> http://www.jcrystal.com/products/krystalshaper/ ) It provides a catalog of
>>> hundreds of minerals, plus tools to analyze and export geometry. Might be worth
>>> checking out.
>>>
>> Nice little program indeed! Thanks. Wulff-nets, ha! That was not really
>> my cup of tea... ;-)
> 
> I don't even know a Wulff net is. But based on its appearance, I'm guessing it's
> some sort of mapping between HKL indices and a sphere. Maybe it's a clue to help
> me convert HKL values to planes...
> 
That is correct. It is/was used in crystallography for mapping mineral 
indices and do all sort of exciting things, calculating angles and 
intersections. Only, as a freshman, I was not particularly interested in 
this branch of geology! Hammering away at overturned, anticlinal rock 
sections: /That/ was what life was about! ;-)

But seriously, I do not remember how it worked exactly but it certainly 
could be of help to you I guess. I still have a Wulff net somewhere 
here, gathering dust.

>> The output could be the basis for crystal renders of quality. Not much
>> time at the moment, but I keep in mind.
> 
> What's your camera aspect there? The crystal looks stretched vertically.
> 
For the demo image I didn't bother with the scene details; just used the 
standard scene code provided by the app.

> It is a cool program, I just wish I could figure out my HKL issues so I can do
> more with it. (My previous searches didn't turn up much useful info, or maybe I
> wasn't comprehending what I saw...)
> 
I know what you mean. These are a couple sites which explain the use of 
the Wulff net. There are more of course, but these are fairly basic.

http://www.minsocam.org/ammin/AM25/AM25_689.pdf
https://www.doitpoms.ac.uk/tlplib/stereographic/wulff_construct.php

However, to tell the truth, I remain a bit baffled when I see those 
things again, after all those years. I am not really sure I understand; 
I think you are more familiar with all this.

-- 
Thomas


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