A uniform geometry description for simulation, reconstruction and visualization in the BESIII experiment

In the BESIII experiment, the simulation, reconstruction and visualization were designed to use the same geometry description in order to ensure the consistency of the geometry for different applications. Geometry Description Markup Language (GDML), an application-independent persistent format for describing the geometries of detectors, was chosen and met our requirement. The detector of BESIII was described with GDML and then used in Geant4-based simulation and ROOT-based reconstruction and visualization.