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 Post subject: Brightness at 0 degrees tilt for R.I. = 1.76 COS = 87.1 etc
PostPosted: Sun Mar 17, 2019 1:41 pm 
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Hi,

The numbers above are from Keith Sanker's Sun Twist as per the diagram at the following address:

http://www.rockhounds.com/rockshop/gem_ ... wist2.html

The complete numbers are:

Brightness at 0 degrees tilt for R.I. = 1.76 COS = 87.1 ISO = 94.1

When I 'cut' this in GEM Cad and then read the graph in Gem Ray, I get nothing like these numbers. In the Gem Ray chart I get around 64% for the black dotted line at zero.

I bought the Gem Cad / Gem Ray within the last few weeks, so it is the most recent version.

Why the difference? Where did the number on diagram at the rockhounds website come from?


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 Post subject: Re: Brightness at 0 degrees tilt for R.I. = 1.76 COS = 87.1
PostPosted: Sun Mar 17, 2019 6:37 pm 
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Welcome to the forum Inquisitive,
Many of the designs on Rockhounds.com were rendered using the DOS versions of GemRay, which did not have headshadow functionality until rather late in it's service life.
Setting "head shadow half angle" to 0 degrees should give you the same values as the design page.


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