Daylight - surface directions


It probably is a very basic question but I started wondering the other day and didn’t find an answer.

I know that for energy simulations, room normal surfaces should be facing outwards.

What If i used same model for daylight simulations, where i would like to assign materials to surfaces (rather than polysurfaces) - shouldn’t walls, floor, ceilling be facing inwards?

What If i modelled a light shelf in the window - should it be facing upwards or downwards?

Thank you for your help.

Please check the response from Mostapha in this discussion. For the light shelf, I would recommend running two quick simulations for both the orientations of the shelf to see if it changes the results significantly.