Underneath that node, put another S_Warps node. Set that one to Warp Bubble. This warp node will define the outer edges of the flames to get a nice fiery look. You need to crank up the "frequency" first. That will give the distortion the necessary amount of repetitions to get the edge to look right. Next, drop down to the octaves and crank that up as well. This is all done by taste. A higher res image will need higher values to look correct, so it is a "season to taste" scenario. Here are my parameters:
After you have a warp you are satisfied with, you can now begin the glow phase. You can get really creative with the glows as there are many options in Genarts, so I’ll leave the fun stuff up to you. We are going to go with the standard glow. This first glow will be the "broad" glow that simulates a gentle cast of light coming off of the flame.
Start by cranking up the GlowWidth to something that extends out past the flame. Then go and drop the brightness to something that is very subtle yet still visible. You can also toy with the color to see what type of effect you can get out of it.
Now we need to insert the second glow, but we need to insert it BEFORE the first glow. This is a personal preference so I can see how the second glow affects the first tight glow. This also demonstrates the ability that you have to insert nodes anywhere in the tree you want. Very handy when making changes.
Insert the 2nd S_Glow node before the first one. This is going to be the tight glow. Adjust the GlowWidth to be something that is slightly larger than the flame shape you created. Crank the brightness up pretty high, but don't blow out your whites. Now scroll down in the parameters tab to GlowFromAlpha. This adds a nice little touch of brightness to the center of the flame. Adjust this parameter gingerly. This parameter gets the glow value from your alpha channel usually resulting in a hot white glow.
Now you should have something that looks something like this:
