• Adobe After Effects Expressions

  Perimeter of ellipse

  Posted by Mikael Holmström on October 31, 2017 at 8:11 am

  Hi all,

  Is there an expression that, based on the width and height of an elliptical shape, returns its perimeter?

  Thanks.
  Mikael

  Mikael Holmström replied 8 years, 9 months ago 2 Members · 2 Replies
• 2 Replies

• 

  Andrei Popa

  October 31, 2017 at 10:46 am

  i don’t know of such an expression, but you could use the approximate circumference of elipses geometry formula which is C = 2 * pi * sqrt((a^2+b^2)/2);
  So the expression should be something like this
  a = thisComp.layer("Ellipse").content("Ellipse 1").content("Ellipse Path 1").size[0]/2;
b = thisComp.layer("Ellipse").content("Ellipse 1").content("Ellipse Path 1").size[1]/2;
2 * Math.PI * Math.sqrt((a*a+b*b)/2);

  The expression was added to a slider on a null layer in the same composition as the ellipse layer named Ellipse.

  Andrei
  My Envato portfolio.
• 

  Mikael Holmström

  October 31, 2017 at 12:27 pm

  Thank you! That was exactly what i was looking for.
  Mikael

Reply to this Discussion! Login or Sign Up