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Activity Forums Adobe After Effects Expressions Particular Emit Dotted Line

  • Particular Emit Dotted Line

    Posted by Jeff Mcbride on May 7, 2012 at 8:59 pm

    I’ve got a null from C4D moving around which will act as my Emitter for Particular. I’m trying to calculate the null’s velocity and translate that to emission rate so that I get an evenly spaced dotted line.

    For example, for every 10 pixels the emitter moves particular needs to emit 1 particle in that exact location. If the null moves 25 pixels, particular would emit one particle at 10 pixels and one at 20. The next particle would be emitted when the null moves another 5 pixels. That may be a bad illustration but hopefully it makes sense.

    Any ideas?! Thanks!

    Jeff McBride
    Motion Graphic Designer
    Chicago, IL

    https://www.jeffmcbride.tv

    Jeff Mcbride replied 14 years ago 2 Members · 2 Replies
  • 2 Replies
  • Dan Ebberts

    May 7, 2012 at 9:43 pm

    I’m not sure it’s going to give you what you’re after, but I think it would be something like this:

    pixPerParticle = 10;
    thisComp.layer(“emitter null”).transform.position.speed/pixPerParticle

    Dan

  • Jeff Mcbride

    May 8, 2012 at 3:50 pm

    That’s about the closest I’ve come so far. I think the problem may have something to do with subpixel particle generation? I created a little illustration to help convey where I’m at.

    The first line shows the effect I want, evenly spaced particles. The problem begins when I add easing as in the second example, the particles begin to clump at the ease and stagger a bit throughout. Using the expression you provided gets me exactly what I need except that the particles are just a tad uneven. I’ve got Subframe Positioning turned on but it doesn’t seem to change anything. Is this just a limitation or is there a solve somewhere?

    Thanks for the help!!

    Jeff McBride
    Motion Graphic Designer
    Chicago, IL

    https://www.jeffmcbride.tv

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