subroutine char key_1 char key_2 real DENSITY
! set rad sele segm name SEGMENTS end vdw

make map 3 init 0 unit_cell 100 100 100 90 90 90 \
       grid 200 200 200 \
around 10 sele display end integer

make poin init from atom map 3 surface sele display  end

! dele map nmaps


! poin surf all sele key_1 .a .not atom name H* end \
!       sele  key_2 .a .not atom name H* end dens DENSITY init
return