(form "00686" (size 30 6)
   (help "00686_TIP_0")

  (heading "TRIANGULATION PARAMETERS")

  (label (position  1  3) (text "Constrain interpolation?"))

  (field "constr" (position 21  3) (display_length  1) (input allowed)
   (value_in "Y" "N") (default "N")
   (translate upper) (null allowed) (max_length 1)
   (help "00686_TIP_1")
  )

  (default_buttons)
)