App Note:
Flicker Flames
Candles, Lanterns and Campfires
Flames flicker randomly. Sometimes they flare up brightly, at other times they almost gutter out. The rest of the time they wax and wane in complex, non-repeating patterns. This is a particularly difficult thing to simulate with software. But it's easy to create convincing flame effects using the DMX Machine's scripted show control capabilities. Here's how:

 

President
 
Equipment
Lighting DMX Machine
Show Control

InterActivator

Software
WinScript
Software
dmxflicker.amw

To create a seemingly random sequence of flickers, we'll create three separate looping sequences and let them fight it out. We'll select prime numbers for their durations (29, 13 and 17 frames), so that it will be a very, very long time before their alignment repeats. And even when it does, the initial condition of the output will be different. Each sequence will also try to ramp the output to different levels and at different rates. So for all intents and purposes, the effect will never repeat itself.

Observing the results, this combination produces a very convincing candle. For a lantern or fireplace, make one or two of the sequences loop more slowly. to simulate larger flames.

Because this effect uses only a single channel, it's easy to duplicate it so there are three sequences controlling every flame in the attraction -- each on a separate dimmer. Simply start the sequences looping at different times during the start up routine, and they will all be completely different from one another.

Another trick is to use a spotlight to reinforce the flicker. This works particularly well for lanterns, where the flickering bulb in the lantern is reinforced by a glowing circle around it. Simply wire both light fixtures to the same dimmer channel.

Three battling sequences create a convincing flame effect.





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