Spray

Spray particles are emitted from a flat plane, emerging perpendicular to that plane. This emitter plane can be moved or rotated anywhere you need it in the scene. Create the emitter plane and its Spray particles by following these steps:

1. Choose Create>Geometry>Particle Systems>Spray.

2. Create the emitter plane by using the left mouse button to click-and-drag in any viewport.

   Use the Top Viewport if you want the particles to fall down from the top of the scene.

3. After the emitter plane is created, keep it selected and choose the Modify Command Panel.

   Doing so gives you access to the Spray Particle controls shown in Figure 23-2.

   
   Figure 23-2: The Spray Particle controls in the Modifier Command Panel.

 Tip  Before you start tweaking the Spray Particle controls, preview the present Particle System settings by running a preview of the animation. To do so, simply click the Play button in the VCR controller, and watch the Particle System playback in any active viewport.

You can adjust the controls for the Spray particles in the Modify Command Panel. Under the Parameter heading are four groups of controls and commands: Particles, Render, Timing, and Emitter.

Snow

You definitely want to create the Snow Particle emitter in the Top Viewport, unless you want to use it to create an effect different from snow. The Snow Particle emitter is also a flat plane. After creating the emitter, you can visit the Snow Particle’s controls in the Modify Command Panel, as shown in Figure 23-3.

At first glance, the Command Panel for the Snow Particle parameters looks much the same as that for the Spray particles detailed previously, but there are some important differences.

For example, under Particle Parameters you will find three new parameter commands: Flake Size, Tumble, and Tumble Rate. Flake Size refers to how big a snowflake shape you want to use. Unless you are exploring some strange particle effects, keep this value at or following 4.0. Snowflakes tumble as they fall, and both the Tumble and Tumble Rate values enable you to control the tumbling effect.

One additional new control is found under the Render heading. It’s called Six Point. Clicking it to select it forces all the particles to assume the shape of a six-pointed polygon, just what you need for a snowflake simulation. Figure 23-4 shows such a simulation with the particles mapped in a solid white Diffuse Color; particles farther from the camera render in darker grays.

 On the CD  When zoomed in on, these six-pointed snowflakes look rather rudimentary, like confetti. They serve as basic examples here, but a fancier snowflake form is waiting at the end of this chapter. (Hint: Take a peek at the SnwFlk1.avi animation in the ANIMS folder on this book’s CD-ROM.)

Blizzard

A Blizzard Particle System emitter is usually created in the Top Viewport, though it’s also possible to use other viewports for special effects. The emitter is a plane similar to the Spray and Snow Particle Systems. When you access the Blizzard Particle’s Modifier Command Panel, however, things look different (as shown in Figure 23-5).

Under the Particle Type rollout is a special feature that will thrill you to no end . . . the Instanced Geometry option. Farther down in the same rollout, which you can scroll to, are the Instanced Geometry controls shown in Figure 23-6.

The most important control here is the button that reads Pick Object. Can you guess what it does? If you said “clicking this button enables me to select any 3D object in the scene and use it as a snowflake for a Blizzard Particle System,” you must be either clairvoyant, or you read ahead. That’s right. If you have any 3D polygonal or NURBS object in your scene, you can force the Blizzard Particle System to use it as a dynamic particle form! Here’s how:

1. Choose Create>Geometry>Hedra>Star1.

2. Click and drag in any viewport to create a 3D Star Hedra.

3. Open the Material Editor object, and select an empty preview slot.

4. Under the Shader Basic Parameters rollout, check Wire.

   Doing so creates a Material which, when mapped to any object, forces the object to display only its polygonal edges, as if it were constructed from metal clothes hangers.

5. Set the Diffuse Color/Ambient Color to a bright orange, and set Self Illumination to 50%.

6. Drag-and-drop the Material onto the Star1 Hedra in any viewport.

   Choose Create>Geometry>Particle Systems>Blizzard, and click and drag a Blizzard emitter plane in the Top Viewport. Move it upwards in the Front Viewport.

7. In the Blizzard Particle System’s Modify Command Panel, choose the Particle Type rollout, and then choose Instanced Geometry.

8. Scroll down to the Instancing Parameters in the same rollout, and click the Pick Object button.

9. Click the Star1 Hedra object in any viewport.

   The Star1 Hedra is now the particle to be used in the Blizzard effect animation, as shown in Figure 23-7.

   
   Figure 23-7: The Star1 Hedra falls from the sky in a blizzard-like fashion when the project is animated.

10. Save this project for future rendering.

 On the CD  You can see an example of this animation by opening the BlizPtl1.avi file in the ANIMS folder on this book’s CD-ROM.

PArray

The PArray Particle System has such unique options and controls that two years of exploration would just scratch the surface of its capabilities. Think I’m kidding? Well, consider: The PArray is an Object-Based Emitter — you select a 3D object in your scene other than the Particle System icon to emit particles. That object can be just about anything. Opening the PArray Particle System’s Modify Command Panel displays its wealth of commands and control rollouts, and so does Figure 23-8.

To get a handle on working with the PArray Particle System, use the following steps to modify a Torus Primitive:

1. Place a Torus Primitive in a new scene.

2. Choose Create>Geometry>Particle System>PArray.

3. Click and drag a PArray icon in the Top Viewport.

4. In the Basic Parameters rollout in the PArray Modifier Command Panel, click Pick Object and then click the Torus in any viewport.

   The Torus is now the source of the animated particles that will be created. In the same rollout, you can select how the particles are emitted from the object.

5. While still in the Basic Parameters rollout, choose Particle Formation>Over Entire Surface for the current example.

6. Under the Particle Type rollout, choose (for now) Standard Particles>Sphere.

7. Under the Particle Spawn rollout, choose Spawn Trails.

    Remember  This option leaves the Sphere particle in place after rendering, creating a linear column of spheres over time. You can leave the other parameters at their defaults for now.

   You can always revisit the PArray Particle System later to experiment with a variety of values.

8. Place any Material you like on the PArray icon, which will affect the particle spheres.

9. Place another Material on the Torus. Save the project for later rendering, as shown in Figure 23-9.

   
   Figure 23-9: This frame from a sample PArray animation (which follows the parameters outlined here) displays the Trails effect.

 On the CD  Be sure to take a look at the PArray1.avi file in the ANIMS folder of this book’s CD-ROM.

PClouds

The PClouds Particle System has some parameter control features that the other Particle Systems lack. Foremost among these is that the emitter can be selected from multiple options: Box, Sphere, Cylinder, or Object Based. This enables you to position the emitter more closely to an object it may be linked to, to create particle effects more closely related to specific objects in a scene. After you place your choice of PCloud emitter, you can adjust all the settings in the Modify Command Panel, shown in Figure 23-10.

Another interesting option is that you can set the vector (direction) of the particle spray along any XYZ axis combination. Some other controls are familiar compared to the Blizzard and other Particle Systems, but many give you far more detailed control over the particle effects. This is another Particle System that can keep you busy exploring until you retire.

Here’s how you can use the PCloud Particle System to create some exhaust fumes from an object:

1. Use the PCloud Particle System to create an emitter (for example, an object based on a Sphere primitive).

2. Create a Primitive Tube object, large enough so you can place the spherical emitter inside it.

3. Place the spherical PCloud emitter inside the Tube.

4. In the PCloud Modify Command Panel, select a Standard Particle Sphere as the particle type.

5. Use a Material on the particle that is 50% opaque with an orange Diffuse Color.

6. Try out different particle sizes until you find one that looks good.

7. Under Particle Generation in the Command Panel, choose Direction Vector and set the X,Y,Z values to 0, 0, -1.0. Set the Speed to 10 and the variation to 100%.

   Setting Z to a negative value sends the particles down the Z (vertical) axis.

8. Save the project for a later rendering, as shown in Figure 23-11.

   
   Figure 23-11: A spray of gases, emitted from the tube.

 On the CD  See the PCloud1.avi animation in the ANIMS folder on this book’s CD-ROM.

Super Spray

The Super Spray Particle System is definitely the one to use when controlling the width and direction of a spray of particles is critical. The Super Spray Particle System emitter looks different from the others, displaying the clear directional arrow shown in Figure 23-12.

You can use the Select and Rotate tool to point the arrow, and hence the particle spray, in any direction. It’s also easy to Link the Super Spray Particle System to any object, and to scale and place it wherever it’s needed. After placement, opening its Modify Command Panel exposes all the parameters adjustments, as shown in Figure 23-13.

The other controls match those of the other complex Particle Systems, except the controls for controlling the Spread of the emitted particles.

Here’s a way to use the Super Spray Particle System to create a simple smoke effect:

1. Create a surface with an object on it.

   For example, you could create a rectangular tabletop with a sphere sitting on it.

2. Use any Materials you like to add textures to both objects.

3. Create a Super Spray Particle System emitter with the arrow pointing upward.

4. Create a second object, about the same size as the first.

   For example, create a Torus about the same circumference as the Sphere.

5. Use the Instanced Geometry type in the Modify Command Panel for the Super Spray Particle System, and select a particle shape.

   For this example, I selected the Torus particle shape.

6. Use a brown Diffuse Color with a 50% opacity to map the second object with UVW Shrink Mapping.

7. Place the Super Spray emitter inside the upper portion of the first object (in this case, the sphere).

   When the particles are animated, the resulting effect looks as if the first object is smoldering. The results with a sphere are shown in Figure 23-14.

   
   Figure 23-14: A smoldering sphere.

 On the CD  Take a look at the SupSpry1.avi animation in the ANIMS folder on this book’s CD-ROM.