Support for large high symmetry (e.g. viruses) particles in Ab-initio and Hetero-refinement

[olibclarke]

I think this is a similar failure mode to what we see here:

"side view prior" for ab initio?

Hi, In cases where we have all side views, and no top views, of a disk-shaped sample, ab initio frequently fails in this mode, where we end up with a cylinder, and all the different side views are assigned to views orthogonal to the long axis of the cylinder. Is there any way to introduce some kind of “shape” prior to prevent this? E.g. ab-initio, but instead of starting from random density, start from a disk, or similar? In a case like this the underlying data is fine, and can give a high re…

And I wonder if it could be addressed with some kind of prior (e.g. seeding with spherical density).

I vaguely recall that in cryosparc v0 there used to be an option to do exactly this - @team can you confirm or is my memory failing…?