flex.fmod_positive( coordinates, 1 )

on the fractional coordinates on your sites.

Ralf, is there a better way?

No, Peter's Python loop over the scatterers is currently the best solution. We could add .mod_positive() and .mod_short() methods to flex.xray_scatterer, and then the corresponding two-liners .sites_mod_positive() and .sites_mod_short() to xray.structure. I'll put it on my to-do list. Cheers, Ralf __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com