Benchmark of EM structures used in the optimization of w, the parameter that determines the width and shape of the surface layer of object A.

aThe resolution quoted here is the value in the EMDB; average resolution is given for the pairs of related structures.bR1 is the virtual atoms radius calculated with the central values of the w ranges in column 5.cR2 is the virtual atoms radius calculated with w values derived from the linear dependency of w on the resolution (Figure 1).