[Chimera-users] calculation of volume

Hello all; I am trying to compute the molecular volume of a complex. Chimera first computes solvent-excluded surface area using MSMS. I see it does not compute the surface area of ligand. I am wondering if I can add the extra parameters or atom types for my ligand in some file. I would like to calculate the molecular volume from amber trajectory. Can some one suggest me how to automate the computation of surface area and molecular volume for each snapshot. If you know, please point out the article which describes the procedure for the volume calculation. with regards, Navnit