• Adobe After Effects Expressions

  Moving Null into a circle (clamp expression)

  Posted by Cyril Drouin on September 24, 2015 at 6:44 pm

  Hi everybody,

  I’m using Clamp expression for stop my controller (Null), it’s useful for a character rig.
  But it’s always moving my null into a square or rectangle.
  Is there a way to moving my null into a circle?

  I think i have to use the cos and sin but i don’t know how to mix clamp with that.

  Sorry for my bad english and thank you a lot

  x= clamp(value[0],100,200);
y= clamp(value[1],100,200);
[x,y]

  Hernan Bernardo Vieites replied 5 years, 5 months ago 3 Members · 2 Replies
• 2 Replies

• 

  Kalleheikki Kannisto

  September 24, 2015 at 8:55 pm

  Probably not the neatest code for the purpose, but this does it:

  origin_x=150,
origin_y=150;
radius = 50;
x0=value[0]-origin_x;
y0=value[1]-origin_y;
distance0 = Math.sqrt(x0*x0+y0*y0);
distance = Math.min(distance0,radius);
if (distance0>radius){
distance_mult = distance/distance0;
}else{
distance_mult = 1
}

  x=origin_x+distance_mult*x0;
  y=origin_y+distance_mult*y0;

  [x,y]

  set origin_x and origin_y to the center point of the circle and radius to the radius of the constraint area.
• 

  Hernan Bernardo Vieites

  March 30, 2021 at 7:29 pm

  Hello Kalleheikki Kannisto! I know this post is 6 years old but I found your expression thanks to Google and it works for me. The only problem is that I have to set the values to origin_x and origin_y of a null PARENTED to another layer.

  So the expression I am looking for would be something like:

  origin_x=GLOBAL VALUES OF THE CENTRAL NULL.

  I don’t know if I should use toWorld or toComp or where I should place them to get your expression to work. I hope you read this and can help me.?

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