I was trying to use "volume onesmask" to go quickly from a dusted surface of a low-pass-filtered volume to a mask volume with the same dimensions, spacing, etc. as the input map. 

I thought "fullmap" might be a way to achieve this (the doc says "The remaining options are the same as described for volume mask"), but I don't think that option actually works with "volume onesmask":

Is there a "onesmask"-like operation or set of options that creates an output volume that's on the same grid as the input volume?

Thanks,

Alexis