  Back Projector parameters:=
  ; Example parameter file for specifying the back projector for back_project
  ; This example uses the ray-tracing matrix (which is the default) but would allow you 
  ; to set extra variables
  
    type := Matrix
      Back projector Using Matrix Parameters :=
        Matrix type := Ray Tracing
         Ray tracing matrix parameters :=
         End Ray tracing matrix parameters :=
        End Back Projector Using Matrix Parameters :=
  End:=