BUG: the center of mass was incorrectly set
BUG: the center of mass was incorrectly set

Former-commit-id: d0545e564ce58aae9424cd047a512d965354b290
Former-commit-id: 636327daa7965ffa0bf66d1d8cc819233fa13df9
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox