Flickering smoke

Ok, I followed the tutorial in blender magazine #16 for smoke. The tutorial uses billboards. Now I have the final product and it looks good in stills. But because I’m using billboards, when I try to animate the smoke there is an annoying flickering that happens whenever one billboard passes through another. How can I prevent this:confused:?

The tutorial mentions the “Lock” option for the rotation of the billboards, and I know this helps alot. But I still cannot prevent them from passing through each other as they rotate to face the camera:spin:.

One more thing. In the tutorial it mentions animating the rotation of the billboards using IPOs. It shows images too. But after following the instructions all I can do is make the billboards be born at a fixed and random rotation. Is it possible to cause the billboards to actually rotate as they move? This would definetely add too the realism of the smoke:cool:.


-C. Wynn-