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TimSx
TimSx
Inspiring
August 22, 2017
Answered

set scale in pixels in After Effects using Expressions

  • August 22, 2017
  • 2 replies
  • 19578 views

Hey everyone!

I often set the scale in pixels, using right click on a scale, hitting Edit, and then enter scale in Pixels. How can set the scale using expressions? And generally, how do you set the units using expressions?

returning ["200px","200px"] results in error

Thanks for help!

This topic has been closed for replies.
Correct answer Tomas Sinkunas

Another approach would be to use expression. Apply this expression to scale property and adjust targetSize parameter. It will set Scale to maintain your desired pixel size.

var targetSize = [500, 500];
var sr = thisLayer.sourceRectAtTime(time);
[targetSize[0] / sr.width * 100, targetSize[1] / sr.height * 100];

2 replies

Tomas Sinkunas
Tomas SinkunasCorrect answer
Legend
August 26, 2017

Another approach would be to use expression. Apply this expression to scale property and adjust targetSize parameter. It will set Scale to maintain your desired pixel size.

var targetSize = [500, 500];
var sr = thisLayer.sourceRectAtTime(time);
[targetSize[0] / sr.width * 100, targetSize[1] / sr.height * 100];
    angie_taylor
    angie_taylor
    Legend
    August 27, 2017

    Another tip that will help is that you can set up Expression control sliders to adjust the target size, width and height values, this will give you slider controls that are much easier to access than opening and editing fiddly expressions.

    Just create the sliders, rename them Scale X (Pixels) and Scale Y (Pixels).

    Then make this your expression;

    X =effect("Scale X (Pixels)")("Slider");

    Y = effect("Scale Y (Pixels)")("Slider")

    var targetSize = [X, Y];

    var sr = thisLayer.sourceRectAtTime(time);

    [targetSize[0] / sr.width * 100, targetSize[1] / sr.height * 100];

    Hope this helps :-)

    Angie Taylor

      mylandscapeshots
      mylandscapeshots
      Participating Frequently
      August 18, 2021

      Thank you for this! It's been a life saver 🙂 

      Mylenium
      Mylenium
      Legend
      August 23, 2017

      AE has no "units". All values are intrinsic to the property stream and use its value ranges. Scale will always be in percent. You have to employ your own math to calculate the percentages. Simple 6th grade school stuff. Most commonly people use the linear() interpolator to that effect:

      linear(targetPixels,minPixels,maxPixels,minPercent,maxPercent)

      Simply fill in your numerical values, e.g. for a 1000 px solid:

      linear(200,0,1000,0,100)

      and it will return 20% for the scale.

      Mylenium

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