My students are working on skylighting designs for simple models in Ecotect. They are starting with a simple box with no windows. They insert a horizontal window into the ceiling plane. Illuminance calculations look reasonable. They then insert a roof zone on top of the box, intending to eventually make a 'lay-light' scheme. But before inserting any glazing into the roof zone, they run the illuminance calcs to check the roof was inserted properly - expecting to see no daylight in the lower box. Yet there is a low level wash on the interior.
Anyone run into this before? Any suggestions?
Thanks,
Adam