stbenge wrote:

> 
> Well, yeah :) Minerals have always been a big thing with me. Slowly I'm 
> building up a collection of rendered stones, and some of them will be 
> cut. I use KrystalShaper to get the angles of natural stones. Some will 
> need to be cut stones or cabochons. Peridot (my stone), for example, 
> will probably need to be a cut gem since in nature it seldom forms nice 
> crystals. Rough stones with corroded surfaces are difficult to model 
> accurately1.

Ah, I've actually played around with KrystalShaper a bit. Your 
tourmaline rendering was very nice. Looks like a nice chunk of crystal.

> Cut gems seem to be a hard subject to render. A diamond, like mine, when 
> rendered in such a way as to produce a brilliant white flash, will 
> inevitably turn out looking, well, washed out :( Proper use of a high 
> dynamic intensity range with glare might help, but I think I might have 
> to include radiosity and exaggerated defocusing settings to really make 
> it look real.

Indeed. I'm striving to create gemstones that render nicely, I hope I 
can achieve that. Some of my test renders are showing promise, but I 
have not created a round brilliant cut, yet.

> Your macros look promising. It would appear you are following guidelines 
> very precisely.

I'm following what I can scrounge up on the net. ;)

I've rewritten my macros to be based on a set of faceting macros, Makes 
easy work out of the stones, now. The faceting uses indexing, so you 
should be able to use the cutting schedules output by GemCad to get a 
cut stone in any design. The only guesswork will be on facet distances, 
which will either be a painful process or, if you know what you're doing 
it may be easy. We'll see..

The modifications will now allow you to specify things like crown and 
pavilion angles, which as you know are essential to getting brilliance 
in a cut stone.

> You know, my uncle was a great gem maker. He (and Time books) is the 
> reason I got into minerals in the first place. He would bring tourmaline 
> from Pala, California to show me. Great stuff! I used to just get lost 
> looking at different stones.

Wow :) That would be very cool. I've got a very small collection of a 
couple varieties of quartz, but got really excited when I went to a 
museum in Memphis and saw they had a pretty extensive mineral 
collection. I photographed my favorites. I'm kind of a science nerd, 
which may explain why I like my minerals.

Looking at the refractions on the Lithma renderings I did recently 
really got me thinking about doing minerals and cut stones in POV-Ray. 
Inspiration is funny that way.

> It's a fun subject :)

Most definitely :)

Post a reply to this message