you could check the following: iMOPD}`IX {Oc?C:aI= - if the surface/element tilt is too large !>a&`j2:W F1{?]>G - enough analysis rays used? {Kq*5Aq8 HlOA o:8' - have you used Coherent Data option under Detector setting. gavQb3EP ;:8jxkx6% Someone above was right about that the non-sequential mode only uses geometric rays but you could see inteference fringes using Coherent Data.