POV-Ray : Newsgroups : povray.binaries.images : Apollonian [CG]Sphere packings : Re: Apollonian [CG]Sphere packings Server Time
27 Sep 2024 01:13:05 EDT (-0400)
  Re: Apollonian [CG]Sphere packings  
From: MichaelJF
Date: 17 Sep 2024 15:07:40
Message: <66e9d37c$1@news.povray.org>
> It's interesting that you're doing this with an include file!
> How long does it take to parse the scene that writes the .inc file
IIRC, some 90-120 minutes with 13 generations.

> How much faster does it parse when reading the .inc and not calculating the
> sphere parameters?

10-15 minutes, and you can use the file for other representations. The 
first four images in this post show all the same include file.

> Would it go faster without writing to a file?

Not if you plan to reuse the include-file.

> And you're right - at some point, the size of a sphere will be less than a pixel
> - so why bother.

Especially when one has in mind to depict the spheres as soap bubbles 
one has to avoid very small ones;)

> Now, in order to massively cut down on the number of actual spheres that you
> need to use, I was wondering if you could somehow test for tangency with the
> outer enclosing sphere and only render those spheres. (maybe 1 additional
> layer...?)

That was the riddle. To generate all spheres but only once. Without 
testing. If they fulfill the Descartes-rule tangency test are 
superflous. This is what the rule-set of Claudio Esperanca does. There 
is an article by David W. Boyd from 1973, who developed a similar (?) 
rule-set.

https://www.ams.org/journals/mcom/1973-27-122/S0025-5718-1973-0338937-6/S0025-5718-1973-0338937-6.pdf

But I did and do not understand his arguments.

Best regards
Michael


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