Reply To: How can I give different transmissivity with more than 3 wavelength region?

[gopalakrishna.gangisetty]

Hello Sir, Thank you for the reply and please find the screenshots below : 

Given that the acceleration due to gravity is set in the Y-direction (g=−9.81 m/s2), indicating that gravity acts downwards, the positive Y-direction should be oriented upwards. Therefore, for natural convection modeling in this scenario, the direction of the beam for semi-transparent material should be $X=0$,$Y=1$, and Z=0 or X=0,Y= -1, and Z=0?