VolumeBasedMagneticField(int geomVersion, const std::vector< MagBLayer * > &theBLayers, const std::vector< MagESector * > &theESectors, const std::vector< MagVolume6Faces * > &theBVolumes, const std::vector< MagVolume6Faces * > &theEVolumes, float rMax, float zMax, const MagneticField *param=nullptr, bool isParamFieldOwned=false)