Using Field II Ultrasound _ to simulate beamforming techniques (DAS; MVBF...)

For ultrasound simulation in field 2 that works under Matlab.

I want to get a raw data for further processing to simulate differents beamformers technics (delay and sum beamforming and minimum variance beamforming), and I found difficulties to distinguish between some field 2 command : calc_scat, calc_scat_all and calc_scat_mult.

I was wondering which one would be convenient for me to simulation delay and sum beamforming and minimum variance beamforming