Using the ref_center/extent printed by get_extents (i.e.:
mylog.info('MUSIC cuboid settings:') mylog.info('ref_center = %0.3f,%0.3f,%0.3f' % (xcen,ycen,zcen)) mylog.info('ref_extent = %0.3f,%0.3f,%0.3f' % (xext,yext,zext))
results in a zoom very different from using the ellipsoidal mask, and probably not right (vtk shows the halos being tracked all toward the outside of the volume, and the center mostly a void).
i suspect the issue is this line:
dmin = np.min(ic_dmpos[:,dim]) return dmin,dext
which looks like it's choosing an edge of the box as dmin (though is being passed as the center of the box). super minor issue though since the code isn't actually saying you can use these values as the center and extent of a cuboid music IC.