On Wed, Jul 15, 2009 at 5:27 AM, Shawn Fostner<sfostner at physics.mcgill.ca> wrote: > Field[1].XMax = -50; > Field[1].XMin = 50; > Field[1].YMax = -100; > Field[1].YMin = 50; > Field[1].ZMax = 275; > Field[1].ZMin = 350; > > Thoughts? Something blindingly obvious I'm missing? I think you've got XMin > XMax, &c., so your box doesn't exist; try switching them?