It is very hard as a render effect, it can be simulated with lot of lights (array of them in the shape of your object) and transparecy, but vey intensive to render, I usualy do it in 2D software by rendering a separate mask for object in question and then add some ligts and glow for it in Painter (photoshop is fine too) ! Bryce itself does not have this capability included (objects cannot be turned into lights) like Cinema4D, for example...Hope this helped some ! ;0)