Hello,

I'm trying to thicken a surface that is derived from a lofted solid. However, I keep getting various errors, like "face which failed check", and so on. I checked my surface, and cannot find any gaps, intersections or anything that looks suspicious.

Please help. I'm attaching a part file. I'm trying Thicken command, it needs to be 0.5mm thick on the outside (I tried lower numbers also, didn't work).