

Then I made a couple compared render , 1 of it was plugged w portal material , using PMC :

The other one plugged w a diffuse material (opacity=0) , it suppose to be totally transparent :

It's strange that , the result of these 2 rendering is 100% same . The portal light one suppose to be more full of brightness ... but It wasn't happened ...
I'ld be very appreciate for anyone who can give us any HELP of it !!!