The Fire that tamlin posted is cool, but typically I prefer a more distant view. From my perspective, the fire effect looks too much like a close up of a lighter. I have more use for something that resembles flames like one would see in a campfire or better yet, an inferno. (No, I'm not a pyromaniac

I'm just a car / truck enthusiast who likes the recent trend in true fire paint jobs.). To get what I'm after, I've resorted to using the smoke effect from Eye Candy with appropriate color settings and just applying it in multiple layers to add depth. The blending modes between layers is a trial and error sort of thing that I haven't quite perfected yet.
This example started off with a black background and five separate layers that were clear except for a 1 pixel thick black line across the bottom. On each layer, I simply applied the color-modified smoke filter. The column length, side taper, eddy size, etc. are all the same from one layer to the next. The only difference is the random seed in the bottom of the filter control window.
