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 Post subject: Facet diagram angles vs. Refractive Index
PostPosted: Wed Apr 26, 2017 2:42 pm 
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Is there some sort of angle adjustment calculator for changing angles in the different designs if using lower refractive materials such as amethyst. I'm new here and just got into learning a GemMaster II. Really fun stuff and thanks for any help!


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 Post subject: Re: Facet diagram angles vs. Refractive Index
PostPosted: Wed Apr 26, 2017 11:15 pm 
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Location: Pine City, NY and Dothan, AL
http://www.rockhounds.com/rockshop/gem_designs/tangent_ratio_form.shtml
Much easier with GemCad, which you will want sooner or later.


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 Post subject: Re: Facet diagram angles vs. Refractive Index
PostPosted: Thu Apr 27, 2017 11:55 am 
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AlBalmer wrote:
http://www.rockhounds.com/rockshop/gem_designs/tangent_ratio_form.shtml
Much easier with GemCad, which you will want sooner or later.


Ok cool! Thanks so much for the info!


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 Post subject: Re: Facet diagram angles vs. Refractive Index
PostPosted: Mon May 22, 2017 1:38 pm 
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DaveKlein wrote:
Is there some sort of angle adjustment calculator for changing angles in the different designs if using lower refractive materials such as amethyst. I'm new here and just got into learning a GemMaster II. Really fun stuff and thanks for any help!

Hey Dave, be careful with adjusting these angles. People used to think that you could take a design written for a high RI, use the "tangent ratio" method to change the angles, then cut the material in a low RI, and that somehow it would magically look good. Unfortunately, this only works for a small number of designs, usually designs with a high degree of symmetry (rounds, octagons, hexagons), and the bigger the difference in RI the less likely it is to work.

As mentioned above, you need GemCAD/GemRay. You can play around with the RI and all the angles, then render it to see what it might look like.


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