• Adobe After Effects Expressions

  Limit movement to Comp dimensions

  Posted by Andreas Woelfl on September 22, 2016 at 10:25 am

  Hello everybody,

  I am trying to write a script that allows me to grab and move an element inside the comps borders, but only within the comp’s width and height. So even if I would drag the element outside the comp it would stay at the border of the comp.

  Please find the script that I added to the object in my comp below.

  With the script that I have so far it works visual wise. So the square gets stuck on the comp border when ever I try to drag it outside the comp. The only problem I have is that it seems that if I drag the square for example 5000px to the right outside the comp it stucks directly at the border. But when I want to drag it back in the middle I have to drag it at first 5000px back to the left until I can see the square moving inside the comp.

  Can anybody tell me if I need an adjustment to my code or maybe a complete other aproach?

  Thanks for the help!

  xPos = transform.position[0];

  if (transform.position[0]>1920) {
  xPos = 1920
  }
  if (transform.position[0]<0) {
  xPos = 0
  };

  yPos = transform.position[1];

  [xPos, yPos]

  Xavier Gomez replied 9 years, 10 months ago 2 Members · 2 Replies
• 2 Replies

• 

  Xavier Gomez

  September 22, 2016 at 12:40 pm

  An expression can bypass the value as you did, but cannot prevent you to set a given value.
  I dont think there is a way to do what you want.

  Note: you could shorten the expression, and make it valid for any comp size, as follows:

  pos = value;
  pos[0] = clamp(pos[0], 0, thisComp.width);
  pos;

  Xavier
• 

  Xavier Gomez

  September 22, 2016 at 12:47 pm

  You could also hit P to reveal the position property of the layer, then either :
  right click the position property, > reset to recenter,
  or shift+scroll the x value to scroll faster.

  Xavier

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