Converting PDB file into LAMMPS input file

Hi
I converted pdb file ( “hydroxyapatite” molecule) into lammps input file using command :

writelammpsdata []

but the problem is, it is showing angles=0, diehedrals=0, impropers =0, which should not be the actual case.is there any speciic command in VMD to convert pdb file into lammps input with all angles, diehdrals ??

Thanks

Mahesh