distribute layers on a ring

[Guest]

hi

i've got an illustrator 2d ring file(1000*1000).i'd like to distibute a whole bunch of layers on this ring.

important is now that all layers have the same distance(degrees) to each other.i tried it manually but it is not really efficient.

orientation is also an issue, layers should point in ring's direction.

can anybody help me out with this expression plz?

thx

[Dan Ebberts]

Assuming that your ring layer is at the bottom of your layer stack and is the only other layer in the comp besides the layers to be distributed (I'm also assuming it is named "ring"), you can distribute your layers with a position expression like this:

ringLayer = thisComp.layer("ring");
offset = -50;
radius = ringLayer.width/2 + offset;

center = ringLayer.transform.position;
n = thisComp.numLayers - 1;
angle = index*Math.PI*2/n;
center + radius*[Math.cos(angle),Math.sin(angle)]

Adjust the "offset" parameter (or connect it to a slider) to adjust the distance from each layer to the center of the ring.

A rotation expression like this should handle orienting each layer toward the center of the ring:

n = thisComp.numLayers - 1;
offset = 180;

index*360/n + offset;

Adjust the "offset" parameter as necessary (or connect to an angle control) to get the layers to point exactly where you want them to.

Dan

[Dan Ebberts]

It occured to me that you might want to parent the layers to the ring. If so, you'd need to change the position expression to something like this (which will handle both the parented and unparented cases):

if (hasParent){
  center =[parent.width,parent.height]/2;
  radius = parent.width/2;
}else{
  ringLayer = thisComp.layer("ring");
  center = ringLayer.transform.position;
  radius = ringLayer.width/2;
}

offset = -50;
radius += offset
n = thisComp.numLayers - 1;
angle = index*Math.PI*2/n;
center + radius*[Math.cos(angle),Math.sin(angle)]

Dan

[Guest]

thank u very much dan for your help.

I forgot to mention that i'm working in 3d.The ring layer is like a floor and all distributed layers shall stand on this ring.

A camera will then fly to each layer on the ring.

your expression works perfectly for 2d but with 3d it gets tricky.

[Dan Ebberts]

For 3D, the position expression would look like this (now assuming there is a camera in the layer stack below the layers to be distributed):

if (hasParent){
  center =[parent.width/2,parent.height/2,0];
  radius = parent.width/2;
}else{
  ringLayer = thisComp.layer("ring");
  center = ringLayer.transform.position;
  radius = ringLayer.width/2;
}

offset = -50;
radius += offset
n = thisComp.numLayers - 2;
angle = index*Math.PI*2/n;
center + [radius*Math.cos(angle),-height/2,radius*Math.sin(angle)]

And y rotation like this:

n = thisComp.numLayers - 2;
offset = 90;

offset - index*360/n;

Dan

[Dan Ebberts · Accepted solution]

That last position expression doesn't work quite right if the layers are parented to the ring. This should be better:

offset = -50;
n = thisComp.numLayers - 2;
angle = index*Math.PI*2/n;

if (hasParent){
  center =[parent.width/2,parent.height/2,0];
  radius = parent.width/2 + offset;
center + [radius*Math.cos(angle),radius*Math.sin(angle),-height/2]
}else{
  ringLayer = thisComp.layer("ring");
  center = ringLayer.transform.position;
  radius = ringLayer.width/2 + offset;
  center + [radius*Math.cos(angle),-height/2,radius*Math.sin(angle)]
}

Dan

[Guest]

thx thx thx thx

it works like a charm,perfect

one question to this syntax dan:

n = thisComp.numLayers - 2;

you use -2 because you want to exclude the cam+ring layer from the pos expression,right?

[Dan Ebberts]

Yes, that's correct.

Dan