I'd say shoot as green screen, key, then use Particular in After Effects to add the smoke emitters. Actually you could probably have the dancers wear fully body green Lycra body suits and use any background.
Probably shoot the three dancers one at a time as well to avoid too much masking to handle oclusion issues.
Siby said: "I do not understand why did you say "wear green Lycra body suits". Can you please explain."
You can buy full body chroma key green stretchy fabric suits for people to wear.
Having the talent wear one means you only have to generate a mask for them as you don't need to actually see the talent. This could be much simpler than trying to get a full height screen and light it etc, etc. Plus in this case I don't think you need all the hair detail.
As you can see they're mainly made so assistants etc can be in a shot and made invisible. For your project you could do it the other way around. In your CK software select Invert Mask, pretty much job done.
Grazie said: "What Bob wants to wear, is up to him!"
He, he, the company I linked to above has them in XXX-Large so I'm good.
I recorded the video with dancers. applied the background with chroma key. So fard looks very good. But I couldn't figure out how to create the flying colors effect. Can some one suggest what product I should buy. Thank you in advance.
One, I would say you probably will be looking at a 3D program more than particular, based on that smoke, I would guess it was probably FumeFX in Max (if you don't have that, you can certainly look into blender, who's particle FX engines are really coming along), and 2nd you would probably get benefit from having something for the model to hold in their hands that gives you a clear motion track point so that you could then move the emission point naturally for the video.
They announced a new product at NAB for 3DS which is supposed to be easier to use and renders faster called Stroke.
I believe you can download and run all of their software without a licence, it just puts a watermark on any rendered output. Be warned a lot of these kinds of plugins use iLocks (USB dongle thingy). Also from what I've read render times are HUGE but you can split the task over multiple machines.