Ovito calculates Interstitials

OVITO General questions
1

I want to know how the ovito calculates the count of Interstitials. Why are the number of Interstitials calculated by WS and that calculated by expression selection(Occupancy>1) not same?

WS
WS1920×882 116 KB

expression selection
expression selection1920×876 114 KB

2

This is in all detail described here: Wigner-Seitz defect analysis — OVITO User Manual 3.10.0 documentation

To count the number of institial atoms, the Wigner Seitz analysis modifier counts the total number of excess atoms, summed over all sites of the reference configuration. A site with Occupancy equal to 2 has one excess atom, a site with Occupancy equal to 3 has two excess atoms, etc.

3

I got it. Thank you very much.