• Adobe After Effects Expressions

  Translating X position data to -100 to 100 slider range

  Posted by Vanessa Appleby on November 7, 2015 at 7:22 pm

  I have a slider (actual artwork that is a slider) that is part of a graph. It needs to be controlled by an expression control slider with value range of -100 to +100 (-100 is the far left of the slider art, +100 is far right). here’s a picture
  
  The triangle needs to move across the slider as the value changes. Super simple.

  I can’t figure out how to translate the position values of the start and the end points to the -100 to 100 value range of the expression slider. In this comp the start X position value is 0, and the end value is 800. So somehow I need to define the following:

  -100 (slider range) = 0 (x position)
  +100 (slider range) = 800 (x position)

  This is probably simple math, but well, I never paid much attention in math class- too busy drawing! Any help would be GREATLY appreciated. Thanks!

  Dan Ebberts replied 10 years, 9 months ago 2 Members · 4 Replies
• 4 Replies

• 

  Dan Ebberts

  November 7, 2015 at 7:28 pm

  It should be something like this:

  s = (your slider reference here);
  x = linear(s,-100,100,0,800);
  [x,value[1]]

  Dan
• 

  Vanessa Appleby

  November 7, 2015 at 7:44 pm

  YOU ARE A GENIUS! This works perfectly! Thanks soooo much!
• 

  Vanessa Appleby

  November 7, 2015 at 7:57 pm

  Nevermind. I got it. here it is for Y in case anyone else needs this:

  s = thisComp.layer(“VALUES”).effect(“Value1”)(“Slider”);
  y = linear(s,-100,100,0,800);
  [value[1],y]
• 

  Dan Ebberts

  November 7, 2015 at 8:01 pm

  try changing the last line to:

  [value[0],y]

  Dan

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