ok thanks it worked but now the one that was see-through is black. i removed the link between the two middle ones and recalculated the normals to be outside on both. i was expecting this to fix the problem and didn’t have the sligtest worry so i just did a quick render BUT THAT ONE WINDOW WAS STILL BLACK!1!! yes the normals on all the windows are outside and no there is no link between the two middle ones.