Hello,

I am trying to do something seemingly simple, but can't figure out what I am doing wrong. I have an mrc map open as model #1, moved the center of rotation somewhere, then generated a sphere with:

shape sphere radius 30 center cofr

I got a sphere as model #2, good. Then I want to turn this sphere into a mask, which I try doing like this:

volume onemask #2 ongrid #1

At which point I get this error: Expected a density maps specifier or a keyword

The documentation of 'volume onemask' says it needs a surface specification as the first argument, and the model panel shows that there is no surface associated to the sphere (then why/how is it displayed? not sure), so that all seems to make sense. And I am stuck at this step: how do I turn this sphere into a surface so I can generate a volume from it? I read the documentation for 'surface', 'volume' and 'shape' but can't find anything to solve this problem.

Thank you in advance,