As Ringo said, when using a background or a sky atmosphere for a GI skydome, you MUST set the intensity . Indeed, it's zero by default, so you won't see much more than a big slowdown in your rendering . On this render, the skydome is at 150 and the light at 25 . There will be a lot of issues concerning the new engine . It always take time to maste a technology . Hey Ringo, remember the dumb questions we had some time ago ? ;) litst