In the previous article by Reynante Martinez, we saw the disintegration effect in Blender's Particle System. In this article we will tackle some more features of Blender's particle system which are as follows:

• Multiple particle systems
• Boids

(For more resources on Blender, see here.)

Multiple Particle Systems

Sometimes, singular particle systems are not enough to create the effects we want. This is when multiple particles come in, enabling us to create things like welding sparks, fireworks, rain splash, object shatters, etc. Thankfully, we have Reactor Particles which does just that. In most cases, reactor particles are born when other particle systems' events happen. You'll see more of that later in this part. I guess the best way to explain these things is through valid examples.

Let's begin by simulating the fireworks effect we see during New Year or when there are festivities. First thing we need to do is to setup our scene. We'll be creating a very simple setup for now and it's up to you to take it further when needed.

Fire up Blender 2.49 (sadly, Blender 2.5 doesn't support reactor particles yet) and orient the camera such that it is facing towards the positive y axis, as shown in the screenshot below:

(Move the mouse over the image to enlarge it.)

(Positioning the Camera)

Next, delete the default Cube and add a Plane object then position it just below the camera's view. You can scale it according to your liking but we can also adjust it later on if need be. Let's name this plane “emitter”.

(Plane Added in the Scene)

With the “emitter” object still selected, go to Object (F7) then click on Particle buttons and add a new particle system.

(Adding a New Particle System)

This particle system will be the single burst that will eventually give birth to hundreds of particles later on. Let's name it “single” for easier reference later on. Keep the amount at a minimum, probably something like lower than 20, so it won't get too chaotic later on once the bursting of particles begin. Also change the Life of the particle system such that you see them die on your camera's view, otherwise we won't be able to see the bursting effect happening at all. And lastly, increase the Normal value under Physics, this will tell how the particles are shot and how fast. You might also have to edit the Life later on once you have decided on the Normal settings.

(“single” Particle Settings)

(Single Frame from the Particle System Animation)

Now if we play back our animation, it should look something like this:

(fireworks_1.avi)

Next is the main particles for this system – the burst. With the plane emitter still selected, head over to the same window where the Particle System was created. On the upper right hand corner of the Particle System tab, you'll notice a portion there with “1 Part 1” on it with arrows left and right. These are indications of how many sub-particle systems there are in our main system. Our reaction particles would not act if it was a different system, so this is one crucial part. Where you see the 1 Part 1 area, click on the right arrow to register another sub-particle system, making it a “2 Part 2”. Then click on Add New again, just like how we did in the previous part.

(Adding a Sub-Particle System)

The important options that we have to take note here are the particle system type, emit from values, and target. With the Physics option, I'll leave it to you to tweak around.

As you might have already guessed, we must first and foremost, choose Reactor as the particle system type, otherwise it would be useless doing so. Next is to change from which will the particles be emitted from (emit from), choose Particle since we wanted it to be emitted from the first particle system that we created. Then in the Target portion, you can choose from which system will it be emitted from, the default which is Psys:1, you can change this setting accordingly depending on which order you want it to be emitted.

(Reactor Particle System Settings)

Then here's the hardware rendered version of the system:

(fireworks_2.avi)

And that's about it! This is also applicable to things like welding sparks or rain splashes. If you want your particle reactor to happen on object collision, instead of setting the particle reactor to begin on Death, change it to Collision then set your objects as collision objects. You can check Part 1 of this article to see more on the material settings. And just a bonus, I've added some tiny details to particle system. You can check out the video below and also download the .blend file.

(fireworks_3.avi)

Boids

Particle boids, are by far, one of the most underestimated and overlooked strengths of Blender's particle system. Not only is it very daunting at first, but the complexity it can offer you is mind blowing.

Simply put, Particle Boid or Boids Particle System is a type of Particle Physics whereby it follows rules and protocols that a user has set. These rules may range from prey and predator relationships to advanced crowd simulation. They can be related to artificial intelligence in ways that each particle point can behave differently and act on its own regardless of the other particle points present in space.

I don't, however, claim to have really surmounted boids particle systems, even before in earlier versions of Blender. It is so exciting and exhilirating yet frustrating at times. To fully comprehend it, you need lots and lots of patience, probably more time to tweak around, and a note near you to have the settings listed down.

For the sake of this article, I'll keep this introduction to boids particle system as simple and as quick as possible, giving you more freedom to experiment and just give you a basic understanding on what this particle system is all about.

Let's get going, shall we?

Fire up Blender 2.53 and delete the default Cube in your scene.

(Deleting the Default Cube)

Next, we need to add the basic elements for our basic boids particle system. It includes 1) an emitter, 2) the visualization object, and 3) the goal object.

With the cube deleted in our 3d viewport, add a plane object (or anything you wish) and leave the default levels of division as it is, this would act as our particle emitter. Name it “emitter”.

(Plane Object Added)

Next, add a simple UV Sphere above the plane, this would then act as our goal object. Smooth the shading and scale to something like 0.200. Name this uv sphere as “goal”.