Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uflorida!stat!vsserv!geomag!prem
From: prem@geomag.fsu.edu (Prem Subrahmanyam)
Newsgroups: comp.sys.amiga
Subject: Re: Turbo Silver Materials
Message-ID: <172@vsserv.scri.fsu.edu>
Date: 7 Sep 89 03:39:31 GMT
References: <2550011@hprnd.HP.COM>
Sender: news@vsserv.scri.fsu.edu
Reply-To: prem@geomag.UUCP (Prem Subrahmanyam)
Organization: Florida State University Computing Center
Lines: 34

In article <2550011@hprnd.HP.COM> marco@hprnd.HP.COM (Marco Gonzalez) writes:
>	My questions is: Can somebody working with Turbo Silver tell me how
>to get materials  Glossy, Mirror, Metal and Glass??. I specially have problems
>with Glass, it simply doesn't come a bit close to what Sculpt 4D does with
>this material ((It looks soooo realistic ); Turbo Silver seems to distort
>the objects behind or onside glass balls beyond recognition!.
>	I will aprecciate any clues.
>
  Well, I don't know much about Turbo Silver, but from what I've heard,
  it's supposed to mimic refractive distortion.  The amount of distortion
  is based on the object's index of refraction, which is probably allowed
  to be set by you....to get glass that does no distortion, set the index
  (if it's allowed) to one.  This will cause a ray passing from air (index
  one) through an object of index one to not be distorted.  Again, I don't
  know if this is user adjustable or not in Silver.  I know the public 
  domain ray-tracers (QRT and DBW_Render) will allow user adjustable
  indices of refraction.  

  As a side note, if Sculpt was not showing the distortion, then it is
  actually the one that is soooooooooooo unrealistic.  Try placing a glass
  ball in front of an object and see if there's not distortion taking 
  place....hint, there is.  

  Again, I'm not sure if Silver will allow you to do this or not (it
  does put a lot of power into the user's hand, as an index of zero
  will crash the program (cause a div by zero error due to the equation
  used to bend the rays passing through the object)).  Good luck in
  finding the index.....
  ---Prem Subrahmanyam

  p.s. look for an enhanced version of DBW 1.0 in the next month or two,
  it should crunch a picture faster than anything around. 

  used to "bend