You've pretty much nailed down the export shape function to get the explosion flame cloud shape figured. The sparks were done by fussing with the particle fountain in Carrara. I've never used the fountain in RDS but I set the fountain to run for a short time with a wide range of velocities with a wide range of lifetimes. That means you get a very interesting dispersal of sparks and lifetimes. Your comment about the shadows is dead on. The light is just one bulb with the cross screen and glow turned on. I also turned on the falloff to maximum and limited the range so it would actually sort of disappear at the right moment. I'm really impressed with the way the disc turned out. I'll see if I can recreate the explosion stuff and send you some detail. I did it quickly late at night and I don't remember too much more than what I've said already. One weird thing about it is that if you do the trick I employed, you can't make the object completely invisible. I think it gets confused with the fronts and backs of some of the fills of the shapes.

-Kix