[yt-users] small projections

[Charles Hansen]

Is there a way to call add_projection on a plot collection without 
projecting through the entire simulation domain?  I'd like to do 
projections on small sections, which should be much faster.

Currently, the only way I know to make a small projection is

pf = load(file)
pc = PlotCollection(pf)
p = pc.add_projection(field, center=x)
p.set_width(something small)

This wastes a lot of computational time projecting area I don't want to 
plot.

Ideally, I'd like to be able to do something like

pf = load(file)
sp = pf.h.sphere(center, radius)
pc = PlotCollection(pf)
p = pc.add_projection(field, object=sp)

I could probably put something together using the volume renderer if 
there aren't other options, but that doesn't sound very fast either.

Charles