Hey guys!
I'm a bit stumped. I have an animated piece of geometry (something like a box that's twisting along it's length) that I need to grow from nothing into the full geometry. I'm trying to get it so it appears that it grows from one end to the other and forming from mist or steam. My the geometry growing as it should (Basically, a volume growing from point A to Point B so it's not just growing surface geometry.) But, I'm flummoxed on how to work the particles. My first thought was to animate it backwards using a Dry Ice solver, but then then I'd run into the problem of the end result being obvious that it's just a sim played backwards. I'm finding lots of tutorials and info on how to get an object to dissolve, but not really anything on growing an object out of a particle system. Any ideas would be appreciated!

Check out Varomix's particles along curve tutorial. It shows how to convert and object and scatter it along a curve.
https://www.youtube.com/watch?v=pBZM387_SYg [youtube.com]

For growing your box you could try something as simple as an animated Clip node along a single axis. One of the oldest ways to reveal an object over time. Follow it up with a polycap if you need a capped end.

Sorry for the late reply. The project has evolved to not needing that effect anymore. But, I'll keep that in mind for the future, thanks!