Hi, I am trying to make a mold for a winglet, (for a radio control glider), in SW. I've drawn my winglet and put a parting plane surface on it. I thought I could align 2 sides and align one parting face plane with another and then Insert - Features - Cavity on the mold block but it is not letting me, SW tells me that The Operation Failed Due To Geometric Condition. I've tried this on the upper and lower molds, (there's a re-entrant feature on the lower mold), same result. Does anyone know why this might be happening? I'm having trouble attaching my SW file to this question, "The uploaded file does not have an allowed extension." Can anyone advise how to get round this? Brgds Mark