I'm trying to make a projection of an Enzo dataset using yt-3, showing the maximum level along the line of sight.  This command:

ProjectionPlot(pf,"x","grid_level",weight_field=None,data_source=reg,width=(0.25,'unitary')).save()

definitely seems to make projections of grid levels, but I'm not convinced that it is the maximum level along the LOS.  Is there a better way to do this?

Thanks!

--Brian