Ok I’ve made a big animation in flash but my rookiness has shown through and rather than using masks, I have kind of created my own by putting shapes the same as the background colour over the top of the lines I am revealing. I would convert these to masks but masks work in the opposite way (displaying what appears within the overlap, rather than hiding it like my invisible top-layer shapes). Anyway, it would be quite alot of work to completely re-do the animation but I will do it if I can get better performance. Does anyone know if all those moving shapes are slowing this animation down? I mean flash doesn’t actually have to render anything because they are the same as the bg, but I guess it doesn’t kow that, and it still has to calculate the same amount. But are masks any different?