Blender 3D/Faire du feu
Ce tutoriel constitue une introduction au système de particules de Blender en proposant la création simple de feu et de fumée. Ce n'est pas la seule façon de créer de tels effets, et un expert de Blender pourra probablement le faire de façon plus économique et efficace. C'est un effet simple qui a pour but de vous permettre d'apprendre certains aspect de l'animation basique des particules.
Prérequis.
Pour pouvoir réaliser ce tutoriel, vous devez être capable de :
Régler l'espace de travail.
Démarrez avec la configuration par défaut de Blender et configurez votre vue comme un affichage à deux panneaux de la fenêtre de vue 3D principale et un panneau plus petit en dessous pour la fenêtre des boutons.
(Note - you can also use the rotate widget to point the camera, but I'll leave that for a different tutorial).
(Beginner note: I had YaFray set as my Render Engine and could not see it. Switching back to Blender Internal allowed me to see it again.
(Note - you can also create a TrackTo Constraint for the camera, so that (almost) whatever you do to the camera, the icosphere will be centered. Do as follows: Select the camera, then the icosphere. Press Ctrl+T and choose TrackTo Constraint. Move the camera to test it out.) 
You should now have an icosphere with halo effects at each vertex that looks like this:
Making a Smoke Plume.
Smoke is easiest to model, and learning it first will give you some insight into the particle system. Begin by making a simple particle emission that you can see in the view window as follows:
Simple Particle Emission
Before going further, Press the F12 key to make a quick render of the current state of the object. What you should see at this point is nothing, or a small white sphere. Your icosphere appears to have vanished, or gotten smaller. This is because you have now declared all its vertices to be nothing more than particle emitters. Also, the particles have no visible attributes at this point, so there is nothing for the renderer to see. (NOTE: Using Version 2.42, following these instructions produces a small halo object at the center of the sphere)
With the icosphere selected, make the following two changes to the particle system:
Notice that the view window now shows a stream of particles (You MUST be in OBJECT MODE to see particles) jetting out from every vertex in the icosphere, making it look like a star. Use MMB to rotate the view so that you can appreciate the symmetry of the particle stream. Press KP 1 to return to front view, or KP 7 to return to top view.
Press F12 to make a quick render of the changed object (see image). You should see something that looks like a white explosion. You may have to reposition the camera to see the entire thing. Each particle is rendered as a glowing ball, but the particles are fairly large at this point, and you cannot see them as individual particles.
Use the following procedure to make the particles smaller. At this time, you will also give them a color and some transparency to make them look a little more like puffs of smoke.
Smoke Particle Material
The default colour is light grey, which looks a litte bright for smoke. We'll adjust some of the particle attributes next:
Smoke Particle Attributes
The preview sample might now look as if it has vanished. However, press F12 for a quick render and you will see that the former white explosion has now become a star of smoke puffs. This pattern is still too organized and regular to look much like smoke, but you are getting there (see image to right).
To model the smoke, press F7 to display the Object buttons in the buttons window again. When you first set up the smoke model, you set the particle emission as "Static". However, you want your smoke to build and to move in the final model, so the next step is to randomize the particles and make them move like drifting smoke.
First, let's look at the default animation of the smoke particles:
Before you proceed, take a quick look at a rendering of the animation as follows:
What you should see is a cloud of smoke puffs starting from the location of the icosphere (which is invisible) and radiating outwards. it looks a little like an explosion of smoke, but is still too organized and regular to appear as smoke.
Now that you have invested some time in creating the animation, it might be worth saving the .blend file. After you have saved the file as smoke1, you can experiment with making the particles look more like smoke. Go back to the section titled: 
Smoke Particle Attributes 
and experiment with the values of Halo Size, Hardness, Alpha and the color of the smoke. You do not need to create a new material, you only need to change the existing RGB and A values.
For example, a Halo Size of 0.900, an Alpha value of 0.100, and a hardness value of 1.0 will produce a denser, more realistic smoke. After you finish experimenting with the values, use these values and save the file again. 
Randomizing the Smoke Particles
If you are modelling smoke from a fire, you want the particle system to move randomly, but to drift in a predictable direction as if moved by a breeze or simply billowing up from a source of fire. 
Blender's particle interaction options provide some sophisticated ways to control particles and make them interact with the environment. However, for this tutorial you will simply specify some variables that randomize the particles and move them in the desired direction. You can learn about particle interaction later.
To set up the model, first revert to a static view of the particles, as follows:
What was formerly an organized star of particles has now become a random mass. You can now preview the animation as follows:
The cloud of particles now drifts randomly to the right. Preview the animation as follows:
You should now see a much more realistic drifting cloud of smoke. However, one of the problems with it is that you can still see a pattern of particle emission from the vertices of the object. One way to make this less visible is to reduce the scale of the object, squeezing the vertices together, although that will make the source of the smoke appear very dense. Using the mesh edit decimator option to reduce the number of vertices will make it less dense, as will ramping up the Alpha value of the smoke halo.
The *BEST* way to truly randomize particle emission is to select the emitter and go into edit mode (TAB key), select ALL vertices of the emitter ("A" key), go to the Editing menu (F9), and then to the Mesh Tool Subpanel. There, press the HASH button, then leave edit mode (TAB key). You will now see particles emit in a TRULY random fashion, something that has been overlooked by nearly every other tutorial available.
There are many other ways to make the smoke look more natural, such as by animating the value of Alpha or color to make the smoke seem as if it is getting thicker. You can use several emittors to send out particles of smoke of different color and density, with different rates of emission. By animating emittors, you can create a very realistic effect - or even a moving cloud system.
However, for this tutorial, we will keep it simple, and move on to the next step of animating simple flames and sparks to mix in with the smoke.
At this point, you can save the file, and then experiment with changing the values of the particle system to see how it affects the smoke. The following image is using Halo size 2.0, 2000 particles, Alpha 0.5 and the "Hash" randomizing technique described above.
Making Fire.
Fire makes smoke, so save the smoke .blend file for later. Now, press F7. Under the particle motion tab, set X and Z to 0.00.
Then, press F5 into the materials tab. What colours the fire are, you choose. Right now I'm going to go with orange and yellow. Change the material to R=1 G=0.273 B=0. Press F6 to go to the texture panel. Click Add New and set Texture Type to Noise. Then, go back to the
material buttons and you will see an orange puff with purple in it. Purple? In a fire. That won't do, so go to the Map To panel, and change R to 1, G to 1, and B to 0. Now, the big puff is orange with yellow. That's better. 
Go back to the physics tab (F7) and turn static back on. If you take a quick render, you will see the equivalent of a burning gas giant called our sun. Set Z to o.50, and Norm to 0.010. Now take a render. This looks like fire. Now go to the render settings (F10) and set the output folder to whatever you want by clicking the little folder beside it. Save the fire .blend file. Press Anim to save the animation.
Bingo presto, you've got a fire.