T3D Re: A Third Simple One

["Greg Wageman" <gjw@xxxxxxxxxx>]

From: Bruce Springsteen <bsspringsteen@xxxxxxxxx>


>Number one seems obvious.  But number two confuses me.  Is this limit
>of comfort documented?  I can fuse on my index finger 1 ft in front of
>my nose, then quickly re-fuse on a cloud behind it, effectively at
>infinity.  It is jarring, yes, and I certainly feel the eye muscles
>working - but not really that uncomfortable or unfamiliar.

In the natural situation described, your vergence and accomodation
(plane of focus) are changing together in the natural way.

In the stereoprojection situation, your accommodation is fixed at the
plane of the screen, and you are forced to decouple vergence changes
from accommodation in an unnatural way.  Note also that projection and
handviewing differ from each other both in the degree of vergence
required (a function of magnification) and where that plane of focus is
(actual viewer-to-screen distance for projection, "infinity" for
handviewing).

I believe there is a wide range of tolerance among people in coping with
this.  In particular, younger eyes are generally going to be more
flexible.  However, some degree of practice and experience also come
into play.  So younger, experienced stereo viewers will likely show the
greatest degree of tolerance for OFD, and older (40+) inexperienced
viewers will probably show the least.

     -Greg W. (gjw@xxxxxxxxxx)



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