Cigarette Smokin’ Babies


Page 4 of 7

Koosh, back at his desk, lights up another cigarette and tosses the rest out into his trash bin. The smoke rises from it slowly, dancing to the forces of the air around it. It changes direction as it is driven up to the ceiling by its own heat, slowing and speeding in subtle shifts, thickening and thinning in bands and segments, and slowly it fades away like a forgotten lover in a distant past.

Now this is perhaps the most important part of the process, the attention to motion placed on the reference will be instrumental in making an effective smoke stream. [an error occurred while processing this directive]
Figure 7. (Click image for larger view.)
At this point, our little Koosh has a stream of smoke that rises and wafts in a pretty straightforward manner. What he needs more of is nuance, though. So, to that end he creates another field, a drag field, and connects it to his smoke particle object.

This sort of field creates a drag for the particles connected to it; slowing down whatever movement they are in. He will want to use this field to slow only a particular segment of his smoke stream, as opposed to the whole.

Selecting the dragField1 object, he opens the attribute editor and turns on the Volume Shape attribute to the Sphere setting. This will make the field into the shape of a sphere. The field will affect only connected dynamic objects inside the volume of this sphere. He turns the magnitude from the default 0.05 to 2.4 and begins to position and size (using the regular Maya transform tools – Move, Scale, Rotate) the spherical field to a good place in his smoke stream, right about in the middle. Figure 7.

In this manner, the smoke will rise, then hit a lull in speed and as a result collect and thicken and then speed up and thin out as they exit the drag field’s sphere and head toward the radial field up above.

Figure 8.
Resisting the urge to take a break and fire up Ebay to look up “latex” as he likes to do, he finishes off his glass of gin and gets real close to his monitor. Watching his particles over and over, he determines he needs one more turbulence field to break up some of the stream at the top. He’s unhappy with how they clump together as they near the radial field.

He clicks Fields>Turbulence, and connects them to the particles, again through the Dynamic Relationships Editor. As with the drag field, he turns on the Volume Shape, but this time to Cube.

It is entirely possible for him to avoid using the volume shape by turning on the field’s Use Max Distance attribute and setting an appropriate Max Distance value to allow the field to only affect the particles within that radius, but it’s simpler and more visual to turn the field object into a volume as place it as needed.

In this case, it’s placed above the drag field’s sphere, intersecting with its upper third. This will allow the smoke to dissipate a bit towards the top of its flow. Figure 8.

“I need more gin,” he declares without breaking eye contact with his screen.

“I need more cigarettes,” she declares, without breaking contact with her screen.

Stalemate.



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