Dear Mark, Thank you very much, things worked out fine exactly the way you described them. Probably a typical beginners mistake to use mm rather than voxel coordinates. The addition of the -thr 1e-8 before the -bin made the second command work just fine aswell. The compution time was not suspiciously long (somewhere around 30 s I would guess). Thank you very much for your help, all the best, Gerhard