$ranges (RayTracing)

$totalregion is a required input tag the total regions to set the material parameters.
This includes the normal rectangular region triangular region and other special shape regions. This command is conflicted with the command $totalparameterregion It usually goes with commands $ranges (RayTracing) and $parameters (RayTracing),

For example:

$totalregion
N_region 

$ranges
$x_L$  $x_R$  $y_{bottom}$  $y_{top}$  
$x_L$  $x_R$  $y_{bottom}$  $y_{top}$  
 ...
 ...   total N_region
 ...
 $x_L$  $x_R$  $y_{bottom}$  $y_{top}$   

$parameters
$n_r$  $\alpha$ 
$n_r$  $\alpha$ 
...
...
$n_r$  $\alpha$ 

 $x_L$  : left range of x  (unit $\mu m$  !)
 $x_R$  : right range of x  (unit $\mu m$ !)
 $y_{bottom}$ :  bottom range of y (unit $\mu m$ !)
 $y_{top}$: top range of y (unit $\mu m$ !)
 $n_r$: refractive index
 $\alpha$:  absorption coefficient

Related commands:
$ranges (RayTracing), $totalparameterregion, $parameters (RayTracing), $totalregion (RayTracing)