2009

returns the remainder after division. For example, 24 divided by 24 returns
0, but 25 divided by 24 returns 1. (Dividing 25 by 24 equals 1 with a
remainder of 1.)
If the value of frame divided by 24 is equal to any number with a
remainder of 0, the assignment to BubblesShape.rgbPP occurs. In other
words, the assignment occurs when frame equals 24, 48, 72, and so on.
At an animation rate of 24 frames/second, the assignment happens once
each second.
The == symbols mean is equal to. In conditional statements, be careful
to type == rather than =. The = symbol means assign the value to.
2 Rewind and play the animation again.
When you go to the start time, the particles turn red because the creation
expression executes. When the animation plays, the particles receive a
random color once each second.
Note that you can change the beginning red color to random colors by
changing the creation expression to this:
BubblesShape.rgbPP = sphrand(1);
This is the same expression as the runtime expression.
3 Save the scene if you plan to examine it later. This concludes the lesson.
Beyond the lesson
In this lesson you learned how to:
■ Control particles using creation and runtime expressions.
■ Apply a random function to your expression.
Beyond the lesson | 589