Volumétricos -tutorial para blender-
Pues hace ya un rato me encontré con un archivo de blender que había bajado hace tiempo atrás de centralsource, el archivo simulaba algo así como un fireball, pero en general.. la “cola” o estela que dejaba seguía siendo fuego, y en ningún momento había ese humo denso de la combustión. así que tomé ese archivo y me puse a analizar como estaba hecho el material para saber que podía hacer para lograr el efecto que buscaba. Al final obtuve resultados aceptables en cuanto al efecto volumétrico, y en las diferentes aplicaciones que se podían hacer, como fuego, humo y nubes 
así como por algunas sugerencias que me hicieron, aqui está el tutorial 
Antes de comenzar agradezco al autor de este ejemplo, no encuentro su nombre pero al parecer lo conocen como Macke ( Gracias Macke!
). Muchos ejemplos interesantes los pueden encontrar en la pagina antes mencionada CentralSource
Este ejercicio está orientado a usuarios regulares de blender, que conozcan la interfaz y conceptos básicos, ya que no los cubro por completo 
Por el momento lo tengo en inglés pero en unos días lo pondré en español.
Fake volumetrics effects
Some years ago I found centralsource web site, and get some blend files about fire, smoke, and another effects that can be done in blender in a easy way. And some time after that I take one of these blend files and I did some modifications in the material trying to get something like a volumetric and dense cloud, and then later by doing another modifications I was be able to do a fireball effect with volumetric look, as in the image below.
Now I think it’s time to write about of this, so.. let’s blending on
- As the first step, we are going to put a box in the scene, with a SubSurf modifier of 3 levels (Control+3key as shortcut for this, with the box selected), and be sure to set smooth all faces, is very important.
- Second step, add a material to the box to simulate the fire and follow the indications below
In the first empty slot put a procedural clouds, with Default and Hard Noise option activated as well as Noise Size and Noise Depth with 2.0 and 4. In the Panel Colors click in the color band and make a gradient color as in the image below.
In the Map Input Panel select Global, Sphere, X, Y, Z and select Color button (Col) and blending mode to Mix in Map To panel, don’t forget to set to black!
The next procedural will be used for intensity and we’ll use a Blend map in linear mode, with their map inputs in Win, Sphere, X, Y, X, mapped to a color channel with RGB values (1, .33, 0) with blendind mode set to Add.
The next procedural wil be a Blend again, but this time set to Sphere mode, with their map inputs in Nor, Flat and Z, mapped to a Alpha channel with Substract blending mode.
Add a clouds map in the next slot with Default and Soft Noise options, set Noise Size to .6 and Noise Depth to 4. In Map Inputs select Global, Flat and Y mapped to a alpha channel with substract blending mode.
In the next slot add another blend procedural and select Sphere in the Blend panel, select Nor, Flat and Z from Map Input panel, and set to Alpha with negative value and set the blending mode to Add.
The material is not really finished yet but let’s see how it looks, just press Shift+P in the 3d window and place the preview window over the sphere. It should look like this:
Nice! Don’t you think? But it looks so uniform and maybe lacks some opacity.
Finally add another clouds map, Default and Soft Noise… well.. just like the image below, follow this and you will have finished the tutorial!
Ready with the last cloud map? Ok.. let’s see in the preview window once again..
The same material, but the last cloud map was changed in the Cloud panel with Hard Noise instead of Soft Noise, Just play arround with map options to see how the material changes. Also you can rotate the scene to see the volumetric effect!
How was made the fireball example? Well is really simple..
Just used the same file from centralsource but with two particle emissors, one of them for the fire effect and the other for dense smoke.
And how to make a dense smoke effect?
It’s really easy! Just change the material color, then deactivate shadeless button and the first two procedural maps and finally set to 0 specular and hard in the shader panel.
And should look like this with some lamps:
For animation I suggest to animate the maps to get more dynamic effect and add some node setup for motion blur, just like the fireball example.
Fireball - Fake Volumetrics from Mataii on Vimeo.
Ready! We don’t have fire/smoke plug in for blender, but blender itself can be capable of do almost anything you can imagine! Blender is great! 
Thanks to Marcus Stade (Aka Macke) to take the time to do and make avaliable their blend files at centralsource
Some video test Fireball, smoke / cloud and Fireball test (animated)
Get the blend file Here!
Download the Rar File (Blend files, PDF, DOC, and ODT)
Download only the PDF
Salvador Mata R. (Aka mataii )
