I remember there was this effect on some site, I think Netdogz, where they had this wireframe thing and they had a building. So what happened was the building's outline appeared, the rest of the building was white or something. Then the building changed from white to coloured from bottom to top or the other way.. How do I do that? ( ps: I wish to do that, but its with a picture of a satellite dish ).. Plz help.