Inside smoke

[bdemetz]

This would be something that wouldnt last forever if you just emit smoke inside of a container and then shut off the smoke density because the nature of smoke is that it tends to diffuse if moving. You might try some techniques such as emitting from particles or a moving object so new smoke is constantly being born and then having the smoke die off before it diffuses too much. You can use ffx noise or wind turbulence to perturb the smoke. The difficulty will be to keep the smoke from appearing it's being born. With some tweaking, I'm sure you can get what you're after.