The o2::fv0::Geometry class represents the geometry of the FV0 detector as used in simulation. It also provides utility methods for retrieving the center locations of the detector cells. See the below example for how to use the Geometry class to query the FV0 cell locations. Note that these are the ideal locations, and that any misalignment is not considered.

o2::fv0::Geometry* fv0Geometry = o2::fv0::Geometry::instance(o2::fv0::Geometry::eUninitialized);
o2::fv0::Point3Dsimple cellPosition = fv0Geometry->getReadoutCenter(chId);
float x = cellPosition.x;
float y = cellPosition.y;
float z = cellPosition.z;