Hi Miguel, I agree that the term non-crystallographic symmetry (NCS) can be confusing. The crystal contacts Chimera tool was developed specifically for fixing the MTRIX records in virus entries in the PDB so the description uses terminology that makes sense for virus crystal structures. I think the crystal contacts tool could be adapted so that the spheres represent individual PDB chains. This would be similar to your earlier request for a tool that just displays contacting chains. But I think the tool you described earlier would be better (only displays contacting chains from entire crystal, shows them as atomic models) and is just as easy to implement. Not sure if I will have time to work on it in coming weeks or months -- I haven't yet scheduled it into my long list of projects. Tom