Slow down an expression

[benio33]

$frameInterval=2;

if (frame%$frameInterval==0)
{
float $x = rand(-0.25, 0.25);
float $y = rand(-1, 1);
float $z = rand(-0.5, 0.5);

particleShape1.position += <<$x, $y, $z>>;
}

This will lunch the expression every 2'nd frame, if you want slow it down more, just increase the interval by integers.

[KungKrille]

Thanks, that was almost what I wanted. The problem is that the changes in position are not interpolated so the particles moves in a jerky way at large intervals.

It´s understandable as they get a new random position at every iteration. Maybe I´m approaching this in the wrong way. I want the particles to move randomly at their initial position but slow and smooth.

[benio33]

Then you should use noise not random.

Create an per particle float attribute - RandomSeed. On creation expression put RandomSeed = rand(-1,1), then in runtime expression after dynamics put:

float $x = noise(time+(RandomSeed));
float $y = noise(time+(RandomSeed*1.1))
float $z = noise(time+(RandomSeed*1.2))

particleShape1.position += <<$x, $y, $z>>;

[KungKrille]

Thank you :) Noise! I shall remember that one. Exactly what I needed :)

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