Ang - in Bryce 6 super easy. Just click on sky and fog and find the last tab that says IBL. This is imaged based lighting. Click open to find your HDRI image and then set the quality slider to zero and the slider below it to the brightness you want. The super large sphere is virtual, but in pre Bryce 6, Agentsmith and bunch of the other guys here used to fake it using the large sphere technique. But Bryce 6 is true HDRI, no sphere needed and the image truly lights your scene. btw - the image needs to be the light probe style. Scott