Re: [ATM] re:Arbitrary ray origins

["Richard F.L.R. Snashall" <rflrs@rcn.com>]

Ellen Mackenzie wrote:
> I received this request and thought someone on the list may have knowledge
> of a program that has this function.
>  
> 1. is it possible to trace an arbitrary ray from an arbitrary surface? E.g.
> by specifying the coordinates and initial ray angles in the local coordinate
> system of the surface?
> 

    Assuming it hits the surface in the direction you want it to, yes.

> 2. is it possible to do a reverse ray tracing w/o reversing the system?

    Assuming you know where you are starting the raytrace from,
    the equations are identical, but:

      a)  The relative refractive index is the numeric inverse of what
          it was in the forward trace of the same surface.

      b)  The distances traversed are the negation of those used in the
          forward trace.



-- 

Rick S.

http://users.rcn.com/rflrs

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