Hugues,

Is this not a lens issue? I only say this because it seems analogous to SLR camera lens distortion.

I've scanned a matchbox sized object that was very square edged and flat, so is not the problem you are doing too large an area. If the surface doesn't have any reference points I can understand it getting confused, and usually this results in a poor texture...but that wouldn't be 6-7mm. interesting post though, and I will do a test, but scanner is offline, as trying to sort out Parallels activation on new iMac... Display Preferences, and projector working OK, and I used the Mac software to calibrate the projector colours, so I hopeful that it will be an improvement, when Parallels uses the native Mac software!

Display Preferences.jpg

Mike