How do I save a map that I applied a gaussian volume filter to?

I opened a cryo EMD map and then applied a gaussian volume filter to it with a width of 1.5 to clean up some of the extra detail. I would now like to save that map out of Chimera to use elsewhere.

When I save the Chimera file it says “EMD-6413.map gaussian was not saved with the session.To have them included in the session it must be saved in separate volume files before the session is saved.” How do I do that?