Dn symmetry definition diferent as relion/xmipp and maybe others

open

#1

We have been converting refinement cs files to star files (using pyem). Our particle has D7 symmetry and in our later reconstructions (using relion or xmipp) were rendering a D14 symmetry. We have looked into this in more detail and we believe that cryosparc defines Dn as Cn around z + C2 around Y, while relion and xmipp, and maybe others, define it as Cn around z + C2 around X.

Therefore, pyem 3d angles conversion is not a straightforward conversion, at least for Dn symmetries.

We think the best, simplest solution to allow packages interoperability, would be to have the same symmetry conventions. Is this something cs can easily change in future versions, or should users/developers be aware of this fact and make the maths to change the angles.