I have some old code in which I pulled particle ids from grid objects, and I'm porting it to yt3.0.  

My old code used a "cut mask" defined like the following:

for grid in data._grids:

    cut_mask= data._get_cut_mask(grid)

I see that grids is now handled through chunks, is there a modern equivalent of the cut_mask?  Or, is there a new-and-improved method to get particle ids from complex objects?

d.
--