Cigarette Smokin’ Babies

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Now that the particles are moving like smoke, Koosh needs to make them look like smoke. He selects the particle object and opens the attribute editor. First order of business is to choose the particle render type. He’s sticking with hardware rendered particles, so cloud, blobby surfaces, and tubes are out. He selects multi-point as the “Particle Render Type” under the “Render Attributes” heading of the window.

This will increase the number of particle points rendered by creating a radius around each particle where additional points will be rendered. This is useful because each new point is not an extra particle, therefore it does not slow down the system. It will give a fuller appearance than regular points without the need for adding extra particles. [an error occurred while processing this directive] Once he selects multi-point, he clicks the button marked “Add Attributes For…Current Render Type.” This creates a set of attributes particular to a multi-point render type, such as MultiCount, MultiRadius, and Color Accum. The MultiCount attribute governs the number of points rendered per particle while MultiRadius defines the maximum area around each particle where these extra points are added. He sets MultiCount to 18 and MultiRadius to 0.9. Turning ColorAccum on will allow the color to accumulate where the particle stream is thicker. This will give more body to the smoke stream.

Figure 9.
Speaking of color, Koosh needs to add a color to the particles. To do this, he must first add a color attribute to his particle object. Toward the bottom of his attribute editor, under the heading “Add Dynamic Attributes,” he clicks on the button marked “Color,” popping up a small window, in which he selects Add Per Object Attribute and clicks the “Add Attribute” button. This will set a color for the entire particle object, as opposed to creating different colors for every particle.

His attribute editor now reflects 3 more attributes under the “Render Attributes” heading, Color Red, Color Green, Color Blue, each reflecting the separate RGB values of the particle object’s color. He sets the particles to a light neutral gray with 0.6 for all three RGB Color values.

Lifespan is next. Even though he is an expression junkie, Koosh chooses the simpler route of setting the Lifespan Mode (under the “Lifespan Attributes” heading of the window) to Random Range. He enters a Lifespan of 20 and a Lifespan Random of 15. The lifespan number will correspond to units of time as opposed to frames, so each lifespan will have a lifespan of 20 seconds with an added random range of 15. Figure 9.

Now the only thing left for Koosh to do, other than apologize to Vicki for the night before, is to make the particles fade out as they die out. To do that, he needs an opacity attribute. So under the “Add Dynamic Attributes” heading, he clicks on “Opacity” to Add Per Particle Attribute. By doing this, he allows each particle to fade out on its own to create a smoother and more natural overall dissipation of the smoke.

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