Pawel Olas - Tutorials

	TUTORIAL5 - step 1/3 Fire&SmokeGenerator run-through. This tutorial will show you how to set up a simple scene with Fire&Smoke. I used the sample scene in the default LW scenes subdirectory /Landscape/CaveFire.lws on the LW6/7 installation disc.
	To start working with Fire&Smoke, you need an object to emit particles from. It may be anything. For the purposes of this tutorial, we will be modifying the Wood.lwo sample object that you got with your LW.
	This object could be used as an emitter without any modifications, but for better results we are going to change it a bit. Just select and copy the part of the object that you want to be burning and paste it to newly created object. Save it as wood_emitter.lwo This object will be used as an emitter in Layout. Particles will be emitted from its surface. You can play with it: for example, you can copy all of the thin sticks and only the middle parts of the thick ones, instead of copying just the middle parts of all of them. Whatever you like. Depending on the shape of the emitter you will get different particle effects later in layout.
	Start Layout and load CaveFire.lws. You can now make a test render to see how the fire looks. Hit F9 and wait few seconds. The result is not that good, but that's because it's an old LW scene ;-) We'll try to improve that. You need to get rid of all unnecessary elements from this LW scene. Remove these objects: FireOut.lwo and FireIn.lwo; we'll create real fire instead of this fake stuff. You can also choose to remove or not remove Sparks; it's your choice. I suggest removing the object to get a better view of the Fire&Smoke particles. Now the scene is ready for you to load the previously created emitter. Parent it to the existing Wood.lwo object to get its proper rotation and direction.
	OK, let's get Fire&Smoke started! Select Wood_emitter.lwo object from the LW pop-up list and open its properties panel ('p'). From the Custom Object pop-up select Fire&SmokeGenerator. You should see this: Fire&Smoke DISABLED!. The plugin is in disabled mode so that it doesn't mess with LW until you want it to. Double click on it to open the Fire&SmokeGenerator settings.
	First we'll only create smoke; we'll create fire later.
	To get access to other important controls of Fire&Smoke, open the Fire&Smoke Control Center from the Generics pop-up menu. This additional plugin allows you to flush all cached frames and set common F&S settings.
	Click START/STOP Simulation to start computing the movement of the particles. As you can see, the default particle settings don't work well in this example, and that's why this scene is good for this tutorial ;-). If you change any of the settings of Fire&SmokeGenerator, your particles won't change their movements. Why? Because their movements are cached. You have to click Reset Simulation to recompute the particles' movements with the new settings. Go to the Emitter Settings panel (if you closed it, you can open it again from the Control Center by clicking the Change Settings button under the Object pop-up. In the Object pop-up, you should have Wood_emitter as the selected object).
	You didn't get good results with the default settings because the emitter object is quite big and you need a few meters of smoke. Change Object Size to 5m This setting tells Fire&Smoke how big your fire/smoke should be. Your cave-fire is probably very hot so change Heat Power to 180%
	We need long smoke, so the particles have to live a long time. Change particle Life Span to 200%. Also, for our purposes we don't need many particles, so setting Birth Rate to 5 is enough.
	Let's try calculating the particles' movements again. Click the Reset Simulation button to clear all previously computed frames. Click Start/Stop simulation to recompute particle movements. The result is better now, but it still doesn't look like smoke. To be honest it looks awful ;-) and completely unacceptable. You probably think now "Hey, you told me that making a smoke is a breeze, but I have to change a lot of different settings and it still doesn't look good!" You are right :-) In most cases Fire&Smoke works fine with default settings or with default settings slightly modified. I chose this scene especially for this tutorial because I want to show you how to use most of the Fire&Smoke controls :-)
	To make the smoke bigger at the top than at the bottom change Expand particles to 40% or more Remember that this setting depends on the shape of an emitter. In this case, the emitter emits patricles in all directions. The 'Expand particles' setting moves particles at the top of some smoke in the directions of the polygon normals from which they were emitted.
	You can also add some wind to this scene. Set Wind X to 0.5
	The main shape of the smoke is ready. Now it is time to properly set up a random vortex. With a few mouse clicks, you will completely change the overall smoke behavior! Go to the Vortex tab. The vortices you already have are too small to change the behavior of your smoke. You need to enlarge them. Set Vortex Area to 1.7m Vortex Radius to 400mm You can also lower the number of vortices - set Vortex probability to 15% Now reset and recompute the particles' movements. Much better! Now it looks like smoke :-) Random vortex sizes (radius, area) have the biggest influence on this particle system. Use them wisely.
	You still need to add color to your smoke. Go to the 'color' tab, open the LW presets shelf, and load any that are available.
	Because it is smoke and we will be adding fire to it, it would be good if the smoke could start over a fire. Just change Appear to 15 [frames] from the particle tab. This means that particles will fade-in during the first 15 frames of their life. You can download the complete Fire&Smoke preset. Recompute the particles to get new values for their opacities (Appear, Dissolve settings). Click RESET and then START/STOP Simulation to recompute the particles' movements. Once you are satisfied with your particles, you can bake their movements and colors to a file and use them later without recomputing anything.
	To render this smoke, select HyperVoxels from the Volumetrics pop-up and Activate the Wood_emitter object. Turn on 'Show LW particles' in F&S settings before activation if you want HV to automatically compute the particle size.
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