Gimp Fire Tutorial
Step 1 - Creating a new image
The Gimp has steadily grown in popularity over the years. It is available on many platforms, including Windows and Mac OS X. There's been a lot of great websites for tutorials on The Gimp over the years, but one tutorial that seemed to be lacking is a good realistic fire tutorial. There's a tutorial on http://gug.sunsite.dk that illustrates one technique for this effect, but it didn't have the chaos I wanted in the flames to make them feel real to me.
Step 2 -Using the transparent layer
For this tutorial, I'll be using a 256x256 pixel image, with a plain black background, as illustrated here. Now, that you have you're starting image, add a transparent layer, which we will use to put the gradient on, for the flames. Note that this image has two layers.
Now, to make the flame truly usable, we're going to want to render it on the transparent layer. This way, we can put the flames on top of another image, and just generally manipulate it much more effectively than we could if it was on the black layer below.
The next thing we're going to do, is select the gradient to use. To start out with, I opened up the 'incandescent' gradient (you may have to copy this gradient before you can edit it) in the gradient editor, and set the black end to Alpha (transparent). Then, I tweaked the amount of white in the gradient on the right hand side. Anyone who's ever seen a plain fire, knows that there is very little white in the flame, and only where it is hottest. I then saved the modified incandescent gradient as 'fire'. Here, you can see it in my gradient list To save everyone the hassle of tweaking the gradient yourself, I'll provide a download link to the finished gradient that I use at the end of the tutorial.
When you are preparing to use the gradient tool, it's very important that you have the settings for the tool properly configured. You don't want to use a radial gradient (circular) to render a flame, you'll just end up with something slightly resembling a sun. You have to make sure that you have the gradient tool set to use a Linear shaped gradient. If you haven't used the gradient editor very much, then the default values should work ok. Here's an illustration of the proper setup of the gradient tool.
Step 3 - Selecting the gradient
Once you have the gradient tool set up, you need to draw the gradient on to the transparent layer. You're going to want to start about half way from the top of the image, hold your left mouse button down, and drag down to almost the bottom of the image. You want to get the gradient drawn as level as possible. You'll get some assistance from the gradient tool by the guideline it draws showing the start and end points of your gradient. Just try to make it as close to a straight line as possible. If you screw up, or don't like the way that the gradient came out, just Undo the gradient, and try it again. It's very important that you Undo the gradient you have drawn, because if you don't, you'll just draw another gradient on top of the old one, basically blending the two together. The results of that aren't all that good looking.
You can download the actual gradient file I use here: Flame.ggr. Just right click, and save as. On unix systems, this goes in your ~/.gimp-2.0/gradients/ directory.
Step 4 - Setting up the gradient tool
I've provided an illustration to help give you an idea of what you are trying to accomplish. As long as what you have looks relatively similar to the illustration in Step 5, you should be in business.
Step 5 - Draw the gradient
Step 6 - IWarp Move tool - Before
Now that we have the gradient drawn, the real fun begins. You'll need to use the IWarp plugin, which can be found by Right Clicking on the canvas area of the image. When the menu opens up, just go to Filters->Distorts->IWarp. Once you open the IWarp plugin, you should see something like this. To simplify things, I have circled the tool you need to use first, which is the Move tool. I have also drawn in the pattern you will want to use to get the desired effect. If you hold your left mouse button down and follow the guidelines as illustrated, you'll be in business.
Step 6 - IWarp Move tool - After
Your results should look something like this. You may have to go over the same spot a couple of times to rough up the gradient a little bit, but you should be getting the idea here. If you get your image all screwed up, just hit the Reset button, and it will revert to it's original state. Keep in mind that this will undo all of the distorts you have done with the IWarp plugin.
Step 7 - IWarp Swirl tool CCW
Now, the next thing you need to do, is add some life to those flames. To do this, you just use the SwirlCW and SwirlCCW tools. These are pretty self explanitory. SwirlCW means swirl clock wise, and SwirlCCW is swirl counter clockwise. This gives the flames the realistic look that we are aiming for. Now, this part is probably the hardest part of creating realistic flames. I have provided some guidelines on this illustration to give you an idea of how to move your mouse. Keep in mind that they are just guidelines, so feel free to experiment with them.
Step 8 - IWarp Swirl tool CW
Ok, we're pretty much doing the same thing as step 7, but we're using the swirl CW tool instead. this is pretty much the last step in this tutorial. Once you get the flame looking how you want it to, just hit Ok and The Gimp will render out the flame.
Well, that's all there is too it. I hope everyone finds this tutorial easier to use than my original version. As with the original, this document is free to use in any way you see fit. Feel free to mirror it, print it, publish it in books, etc. All I ask is that you leave this line in it.
This document, and all illustrations were created by, and are the property of Jesse James Raleigh. www.jraleigh.com
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