"Samuel Benge" <stb### [at] THIShotmailcom> schreef in bericht 
news:46ce1661$1@news.povray.org...
> Thomas de Groot wrote:
>> This render is really beautiful! I'll keep a copy in my private 
>> depository of 'Beautiful images'.
>
> Thanks! I thought I overdid the glare.... it's approaching soap-opera 
> proportions :)
>
>> Miller indices, yes... it's coming slowly back now. I used to have a 
>> 'Wulff's net' to analyse crystal shapes 
>> http://euromin.w3sites.net/Nouveau_site/histoire/dates/pic_hist/wulff11.htm
>> and we used the Miller indices to place the normals of the faces on this 
>> 3D projection...
>
> Thanks for confusing me with that! KrystalShaper has such a projection, 
> but I have no idea what it means or what it could be used for.
>

Yeah, well, this was just a piece of personal oral historical mumbling to be 
sure  :-)

If I may mumble on a little while longer:
I suppose that nowadays, Wulff's nets are not used anymore, at least not the 
paper version, and computers should be ideal for that. What is confusing in 
the image shown on the site I provided are the NSEW mentions. As far as I 
remember, the vertical axis of the crystal is situated at the center and 
perpendicular to the net; you put a piece of transparant paper on the net, 
fixed at the center by a pin so that the paper can rotate around the 
vertical axis; then you are supposed to be able to draw in the crystal face 
projections using the Miller indices, but I don't exactly remember how this 
was done (it was 40 years ago I last did that...). You do not get a crystal 
of course, but projections in the shape of lines and circle segments as well 
as the different symmetry axis indicated by conventional signs.
Mumble mumble.....

Thomas

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