cloudFX

[GregB]

After a brief trawl through the archive I find myself posting to possible ridicule..

I'm trying to create a natural cloud effect (strato-cumulus). I've succeeded on ocasion with a smoke machine in a small studio envirnment where the air doesnt move to quickly, the smoke 'lingers' in the air giving quite a nice effect.... but I can't seem to repeat this in bigger spaces. Any ideas?

[3guk]

Have you not thought of just using some form of Gobo or projection on the the cyc ?? That is what we tend to use, as smoke is just a little too unpredictable in larger venues, with the AC usually wrecking havock with any effects that we want to produce.

[GreatBigHippy]

OT (a bit):

I have a long standing challenge to create a cloud in a box for a friend. Not just vapour, an actual small fluffy white cloud... in a glass box.

One way I thought of to do this (although this is not tested, or maybe not even feasible) is using a smoke ring generator with a very soft breeze behind it...

I saw a demo on how, if you get a box with a membrane over one side with a small hole in it. Fill the box with smoke then tap it, it will produce a smoke ring.

So if you could have this up high, and produce smoke of decent density, and get it to stay together long enough.... it may work.

 

OR:

 

Just project nice looking gobos onto a cyc, or use a scrolling cyc.... much damn easier!

[Ike]

In ninety nine percent of cases your best bet is probably clever use of scenery, lighting effects and/or projection. If it's theatre isn't the suspension of disbelief part of the experience?

 

 

 

 

If you are determined to produce real clouds the most realistic (but by no means easy) option will be using a series of ultrasonic atomisation nozzles to produce a suspension of water droplets. This system works by using either very high pressure water or water and high pressure air supplies to force a tiny but extremely fast moving jet of water into a resonant cavity where it is broken up into an incredibly fine mist. The nozzle assemblies are normally only 20mm or so by 10mm however they aren't particularly cheep (think £30 to £50 each) and some can be quite delicate, because of the tiny dimensions of the jet and cavity (fractions of a mm) they need very well filtered supplies. This system is used increasingly in theme parks, TV and film however it has a number of drawbacks.

 

1,The systems are expensive; after you have accounted for the nozzles (and spares), pipework, water and/or air compressors and installation time things very quickly add up.

2,The systems (probably) needs testing as it is (probably) a pressure system under the Pressure Equipment Regulations 1999 and the Pressure System Safety Regulations 2000

3,It will increase humidity and while not doing it as much as dry ice machines the fact that the nozzles are likely to be up in the rig may well lead to problems if not carefully controlled.

4, You are still going to have to control air currents, while you can overcome most minor problems with nozzle placement unpredictable air currents (such as HVAC switching on and off) must be avoided.

 

Having said all that it is probably the single most realistic way of creating clouds available if you have the time and money.

 

http://www.koolfog.com/ are probably the biggest suppliers to the entertainments industry, my only connection being I'm a regular customer.

 

 

 

 

If you were to go for traditional smoke generating techniques I would go for oil to get a smaller particle size and ensure it hangs better in the air, the problem with this being you may well need lots of crackers to get an even covering. I would tend to stick to machines without an inbuilt fan or with one that can be disabled or turned to "very very slow" with the output at maximum to give you clouds rater than haze and again you will have to be very careful about HVAC and other air movers. Be aware that at high concentrations over extended periods of time you will end up with a thin film of oil over your rig!

[GregB]

Thanks guys. The hazer is were I'm headed. I've tried projections but most of them are a little AmDram for my liking. I had seen a meteorologist experiment with a bottle, some water, and a bike pump to some good effect hence my post...