Le 2022-03-29 à 14:54, Craig Lindley a écrit :
> Hello,
> 
> I came across the attached image the other day that I thought was beautiful so I
> decided to look at raytracing again. I hadn't done any raytracing since about
> 1993 so the POVRAY program has changed quite a bit. I am using the 3.8 version
> of POVRAY and it is amazing. I retraced one of my old images that took 33 hours
> in the 1990's and today on my Mac it took about 10 minutes.
> 
> Anyway. I would like to understand how this image was produced because I would
> like to do something like it for this years Christmas card.
> 
> It seems to be made up of Fibonacci spirals but I am not sure. I looked at the
> POVRAY documentation for these types of spirals but I cannot seem to duplicate
> the image accurately. I would guess that each color is its own Fibonacci spiral
> but how they are positioned so they don't interfere with each other escapes me.
> 
> Any help or suggestions would be appreciated. If anyone has access to the actual
> POV file for this image I would love to have it.
> 
> Thanks in advance.

My proposition :
Start by constructing a single spiral and make it an object with an 
union. Don't give it any pigment nor finish yet.
Next, place several copies of that object, each rotated  so that it's 
constituent spheres are tangent to those of the previous.
In this case, there are height spirals, so, 45° of rotation between each.
In that step, give each spiral it's own pigment and finish.
In the finish, make them reflective with the metallic attribute.

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