As with PC’s particle system, PyroCluster effects are created in a scene, and any initial parameters set, via the create panel, and thereafter accessed via the modify panel. Both panels allow adjustment to the PC effect via the six subsidiary rollouts: Shapes, Particle Age and Particle Distance effects, Fractal-Fury, Illumination and Shadows [Figure 5].

Within these rollouts are the specific controls that allow the manipulation of the inter-related variables that determine the character of the effect, and, practically speaking, allow an almost infinite range of different attributes for that effect. The rollouts open when you click on their blue title-bars, and close in the same fashion. However, you may keep any or all the rollouts open at the same time and scroll between them by moving your cursor in the gray area of the Cebas panels.

When the particle system or object to which you wish to assign the PC effect is set up in your scene, open the PyroCluster Plugin Manager, click on the PyroCluster button and the Create panel opens. Place your cursor over the desired object or particle system (note that it turns into a small cross, beneath which appear the letters AABS - an acronym for Automatic Analytical Binding System) [Figure 6], left click on the object, and almost instantaneously AABS takes over and assigns the PC effect to the object.

 As an indication that this occurs, the initials ‘PC?appear and are thereafter present in the scene in proximity to the bound object as a sign of the effect’s presence [Figure 7].

After the assignment is complete, it is very important to note that the effect and the object or particle system are joined in a hierarchy, and access for selection and modification of either independent of the other is accomplished through the normal trueSpace hierarchy navigation methods or the KFE.

After its creation, modification of an assigned PC effect is accomplished by selecting the particular object/effect hierarchy, moving down through it until the ‘PC?symbol in the viewport is highlighted, and opening the modify panel set by clicking on the tab. All of the current properties for the selected effect will be reflected in the panel and subsidiary rollouts, and you can make whatever changes you wish. You may then close the panel and move on to your next task. If you’ve forgotten to isolate and select the PC effect within the hierarchy, the Modify panel will still come up when clicked, but will be blank.

One additional note is necessary in this discussion of the selection and modification process: if you are working with a high poly count scene, on a midrange or modest system, and you add multiple particle systems with PC effects attached to the scene, you will notice a delay in the selection and hierarchy navigation process commensurate to the additional complexity that you have added to the scene.

A newly created PC effect is equipped with a complement of fairly basic, and rather characterless, attributes (see effect G in figure 1), but the primary create/modify panel [Figure 8] for the effect provides for the setting of Globals whereby a number of the basic characteristics of the effect may be modified: Volume, Density, Luminosity, the Base Color Gradient, and Radius options (settings which alter the way the color gradient is represented in the individual ‘puffs?that make up your effect), and minimum and maximum settings for the particle Base Color Gradient. In this panel you’ll also find the toggles for the activation/deactivation of several of the effects controlled by the subsidiary rollouts, and a useful on/off switch which will enable you to selectively disengage PC effects (useful if you are fine-tuning some settings in a scene that includes several effects).

 Here, if you wish, you can assign one of the built-in basic presets (similar to those displayed in the reference figure 1) via the row of six pictorial buttons in the settings section rather than starting from scratch, as well as load or save a particular PC effect you’ve concocted, or reset the defaults. Each of these presets loads a basic form of a popular effect, which may then be adjusted to create a more particularized instance of that effect:

A great deal of what goes on in the creation of a PyroCluster effect is governed by color gradients and they are fundamental to the controls in the Particle Age and Distance Effects rollouts, and for the color function in Fractal-Fury. The Gradient Control Panels [figure 9] relevant to the subsidiary panel effects you are working with are brought up by double-clicking on the gradient windows in the panel.

A detailed description of the various, and frequently complex, functions of gradients, and subtleties such as bezier gradients, will have to wait, but in the mean time, the online help file, particularly the separate section "Working with Gradients," should be required reading early on in your PC education. However, to aid in your first explorations of PyroCluster, it is important to remember that with the simplest setting for the Base Color gradient ? flat radius ?the color gradient panel represents the color of the "puff" from its center to its outer radius, corresponding to the left to right extremes of the gradient.

To aid in optimizing your effects and minimizing rendering time, pay particular attention to the Volume and Density settings. Maintaining the proper ratio between the number of particles, and the volume and density sufficient to achieve the effect you are after without going overboard (i.e. making the effect more complex and therefore more render-intensive) can pay real time savings dividends. In many cases, you don’t want an effect that is perfectly opaque, and certainly in the case of haze or fog, a lower density setting is fundamental to the success of the effect.

Another important feature accessed from this first panel is the Preview Window [Figure 10].

 Using the preview window, you may view real-time, against either a solid or a patterned background, any settings you have applied to the selected PC effect. However, it is very important to remember that what appears in the preview window is not the entirety of the effect you have created as it acts on its assigned object or particle system, but rather an individual ‘puff?of that effect, just one single dot or tick in your explosion/fire/marsh gas/whatever. The nature of the effect as represented by that single ‘puff?can also be previewed over the life of the particle by use of the slider below the window, reflecting any changes that you’ve keyed in as functions of Particle Age Effects, for example. But, as you can well imagine, in a scene with a particle system consisting of many hundreds of particles, each affecting and being affected by all the others in proximity to it, and the collective whole being affected in turn by the broad range of influences that can exist in a scene ?lights, location, shadows, other PC effects or shaders, and on an on ?this preview can usually serve only as a starting clue to what the final overall effect will look like. Nonetheless, between the preview window, trueSpace’s area rendering tool and a bit of experience, fine-tuning of a PC effect may be accomplished with a minimum of hair-pulling.

Yet another function that is toggled here on the Globals panel is the Intersection function. This function governs the way a PC effect interacts with trueSpace objects surrounding it. Here, an example of Intersection at work serves better than a long-winded explanation. Take a look at Figure 11, a setup of two identical particle systems and PC effects: simple, and for the sake of clarity in this demonstration, over-luminous smoke effects emanating from two smoke stacks.

The effect on the right (which is active in the subsidiary window) has intersection toggled on, the effect on the left has it toggled off. Note the readily apparent, and highly undesirable, penetration of the PC effect through the walls of the smoke stack on the left below the top. The intersection function helps to alleviate this bleed-through, and is dramatically demonstrated by the second tutorial included with PC, the "smoke in the box" effect.

Finally, note also in the first create/modify panel for the PyroCluster effects the small "map" pin symbols located to the right of many of the main functions ?they also appear conjoined with many of the functions in the subsidiary rollouts. These pins toggle a very useful feature introduced in PyroCluster known as Selective Parameter Instancing. This feature is most easily described thus: posit a scene in which you wish to set up multiple objects or particle systems with PC effects, all of which you want to share a certain set of identical qualities, but that you wish to differ from each other in certain other respects. By toggling SPI ‘on?for those settings you wish to be common among all the multiple effects, you lock in those settings, as well as any future modifications to those settings, so that they are consistent for every instance. By leaving SPI toggled ‘off?for the variables you wish to vary uniquely for each instance, you can then adjust those individually for each PC effect in the scene without affecting the others. This is a very powerful tool, and can be a real time and work saver in a lot of situations.

Page Three