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Activity Forums Video Copilot Adapting Speed Particles Tutorial

  • Adapting Speed Particles Tutorial

    Posted by Steven Shanahan on July 29, 2008 at 8:08 pm

    I just watch the Video Copilot tutorial on Speed particles,
    https://www.videocopilot.net/tutorial.html?id=114
    and am wondering if the expression can be adapted for position values, and not the speed.

    The example scene would be a meteor flying towards a laser wall and blowing up on impact; ie, particles are emitted when the meteor reaches the X position of the laser line and they continue at the meteor’s velocity.

    The expression Andrew used for parenting particular’s emitter to the speed of the example text was:

    S=thisComp.layer(“text”).transform.position.speed;

    if(S>500){
    500;
    }else{
    0;
    }

    I tried adapting it to:

    S=thisComp.layer(“Meteor”).transform.position;

    if (S=thisComp.layer(“Laser”).transform.position[0]){
    500;
    }else{
    0;
    }

    But instead of 500 particles being emitted when the “Meteor” reaches the “Laser”‘s X position, particles are being emitted all the time, but there’s no warning that the expression is faulty.

    At this point, I know I can just set a keyframe for the emitter to emit when it reaches the spot I want, but now I’m curious if it can be done through expressions in a more automated way.

    Thanks
    – S

    Benjamin Tattersley replied 17 years, 9 months ago 2 Members · 1 Reply
  • 1 Reply
  • Benjamin Tattersley

    July 30, 2008 at 10:46 am

    movingX=thisComp.layer(“Meteor”).transform.position[0];
    staticX=thisComp.layer(“Laser”).transform.position[0];

    if (movingX==staticX){
    500;
    }else{
    0;
    }

    just make sure your two x positions line up exactly on a frame

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