Guilin Sun
Ansys Employee

Hi Zia,

It is power transmission, the same as the script command "transmission":

https://optics.ansys.com/hc/en-us/articles/360034405354-transmission-Script-command

Please note that it uses the Poyntine vector dot surface normal, and the surface normal is always defined as along positive axis. Therefore the result can be negative. However it does not mean the reflected or transmitted power is negative.Its sign is to be used for other purpose, for example forward and backward propagation.

 

I hope this helps.