I've just had a really frustrating and puzzling experience. The part I have just printed is one half of a puzzle cube and should be 100 x 100 x 100 mm (minus a 0.1 mm offset on each side). X and Y are spot on at 99.8 mm on each axis. The height however, is 114.7 mm - way off! Printed in PLA and Polymaker Polysupport on my E3D Big Box Dual Titan Hybrid I've checked the STL file and it's perfect. I've also checked the Simplify3D generated code file and the final layer has a Z value of 99.8, which should be right. My Z axis steps/mm (printed straight from the EPROM using M503) are 1600 - unchanged from default. Here's my only clue - the puzzle is meant to be 7 blocks high with each block being 14.08 mm tall. The bottom block layer is a bit short at 13.8 mm. The middle 5 blocks are all much too tall at 17.8 mm. And the top layer, the only one without support material, is pretty much dead on 14 mm tall. Any ideas what on earth is going on here?