Recent years have seen to appear some new developments in adapting whole powder pattern profile fitting techniques to severe cases of ill-crystallized materials, including nanocrystallines.

More and more samples show microstructure effects on line profile shape, width and position.

Reasons are obviously the powder diffractometer resolution improvements at leading synchrotron sources, and the increasing number of users.

When the minimal full width at half maximum is as low as 0.01° (2q) (synchrotron data), sample effects are no longer occulted by instrumental effects.

Finer microstructure details are revealed, needing adapted Rietveld software.

A review will be given of the new developments during the last five years, with a special emphasize on the meaning of some oversimplifications.