SIMION 8.0 Issues/Bugs/Enhancements

Issue I371 [70,80,gem,HIGH]
  0.5 gu adjustment for within{hyperbola(...)}
  Noted by emmah-20070309
  Description:
    When using "within" inside your GEM file:

      within{Hyperbola(0,0,25,25)}

    SIMION applies a +0.5 gu adjustment (as noted in the description
    of the "within" command in the SIMION manual).  So, the equation

      (y - yc)^2/ry^2 - (x-xc)^2/rx^2 = 1

    becomes

      (y - yc)^2/(ry-h)^2 - (x-xc)^2/(rx+h)^2 = 1
      where h = 0.5 gu

    However, if you use a "within_inside" instead:

      within_inside{Hyperbola(0,0,25,25)}

    SIMION applies no such adjustment (i.e. h=0).

    Typically, you want this adjustment so that the surface error is
    not just less than zero ("-1 < error < 0") but rather centered
    around 0 (i.e. "-1+0.5 < error < 0 + 0.5").  However,
    the hyperbola becomes somewhat off particularly in the far region
    when defined this way.  Typically this region is less important if
    ions don't fly in that region.  However, you might try the
    following to preserve the accuracy in the far region:

      within_inside{Hyperbola(0.5,-0.5,25,25)}

    Possibly SIMION should instead automatically define hyperbola in
    that way.

  Also noted by davew-20070806
    -- http://www.simion.com/discuss/viewtopic?p=1794#1794 

  Resolve by 8.0.5-production release.