$setradseparately

$setradseparate is the command to set radiative region without using fet's radiative distribution.

The command is

$setradseparate
N_ranges
xmin_1 xmax_1 ymin_1 ymax_1 surface_No_1
xmin_2 xmax_2 ymin_2 ymax_2 surface_No_2
xmin_3 xmax_3 ymin_3 ymax_3 surface_No_3
...
xmin xmax ymin ymax Surface_No_N

if Rad_type <1  then it is used for without using gmsh file. So the radaitive region will appear in the range of 
    xmin <= x <= xmax and ymin <= y <= ymax 
 
If Rad_type > 1, it is designed for gmsh's surface number. So the rative will appear in the range of 
gmsh_surface_No = Surface_No and xmin <= x <= xmax and ymin <= y <= ymax