The fine 3D digitalisation (to 1/10 of a micron) of coins leads to a wide variety of uses both in terms of research and the enhancement of collections. Our work aimed first of all to provide a dataset to identify dies by "deep learning". The 3D process erases colours and shading, and brings out details that have almost been erased. Then, from several pieces, a more complete picture of the dies was reconstructed. The classes of the Riedonan billon were redefined on the basis of the Liffré (Fr, 35) hoard. This has facilitated the iconographic study of this series. In addition, it has been possible to follow the evolution of the diesbreaks, and to evaluate the volume of issues. These scans also open up interesting museographic exploitations, allowing highly magnified views, specific focus on details and 3D prints at various scales.