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Activity Forums Adobe After Effects Expressions Flow parameter = Y?

  • Flow parameter = Y?

    Posted by Ocean Byrne on March 19, 2012 at 5:50 pm

    So basically I am trying to do a sand dunes type of scene using Trapcode Form and I am animating the ‘Flow Z’ of the Fractal Field to make the dunes roll by. Great. At some points they roll by fast, at some points they move slow.

    Now I have decided that I want some random noisy sand texture to the dunes. I tried just applying random to the color channel, but that applies to each point, which doesnt move with the Flow Z, so you get this sliding texture which is kind of cool, but not what I want.

    So I thought I could use a Layer Map in Form to texture my color with a Fractal Noise pattern. Works good, I had to precomp the Fractal Noise, but now it is on my grid and I can change it, the texture, around as I see fit. Cool.

    But I cant quite wrap my head around how to correlate the Fractal Noise’s Offset Turbulence to stay locked to Form’s Flow Z?

    Flow Z is a rate of change, but Offset Turbulence is a set number in space. How do I make said number line up with the movement of Form’s Fractal Field?

    This is what I’ve got so far on the Fractal Noise’s Offset Turbulance, it does move and change via Form’s rate, but it does not stay locked

    Thanks for any help…

    [750, time*comp("Shashkin").layer("Desert").effect("Form")("Flow Z")]

    Ocean Byrne replied 14 years, 1 month ago 1 Member · 1 Reply
  • 1 Reply
  • Ocean Byrne

    March 21, 2012 at 12:40 am

    If anyone is interested, I got it working with the help of sleeping on it, to realize I needed a variable to cumulatively track how much a point has moved based on the FlowZ rate, and then the help of Dan ‘The Man’ Ebberts to figure out how to code said realization.

    The following is the expression I put on the Offset turbulance, so it tracks the FlowZ dunes

    Adder = comp("Shashkin").layer("Desert").effect("Form")("Flow Z");
    f = timeToFrames(time);
    Cumulo = 0;
    for (i = 0; i <= f; i++){
    t = framesToTime(i);
    Cumulo += (Adder.valueAtTime(t) / 30);
    }
    [750, Cumulo]

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