Roving objects position?

[Dan Ebberts]

If “Layer A” and “Layer D” are the end points, one in-between layer could have a Position expression like this:

A = thisComp.layer(“Layer A”).position;
D = thisComp.layer(“Layer D”).position;
A + (D – A)/3;

And the other one like this:

A = thisComp.layer(“Layer A”).position;
D = thisComp.layer(“Layer D”).position;
A + (D – A)*2/3;

There are ways to automate it based on layer index if you have a bunch of layers, but this should get you started.

Dan

[Erin Patrick]

Ok, cool! I didn’t know it was so easy. I’d love to here the “automate it based on layer index if you have a bunch of layers” bit.
Thanks again.

[Dan Ebberts]

If you have a bunch of layers, you could apply this expression to all the layers, then just drag the first one or last one around and the others should spread out in between:

if (thisComp.numLayers > 1){
P1 = thisComp.layer(1).position;
P2 = thisComp.layer(thisComp.numLayers).position;
P1 + (P2 – P1) * (index – 1) / (thisComp.numLayers – 1)
}else{
value
}

Dan

[Mike Clasby]

Dan, I love that expression (second one), but I can’t get it to play nicely with others. When I add any other layers to the comp, they don’t act the same (I wanted to add an audio layer and Convert audio to keyframes to drive one of the end layers with music).

I tried hacking it, like line 3 to:

P2 = thisComp.layer(thisComp.numLayers-2).position;

but no luck. Any insights?

[Dan Ebberts]

Mike, this should fix it. Just set “layersToSkip” the number of layers not participating in the chain and make sure those layers are at the bottom of the layer stack.

layersToSkip = 2;

if (thisComp.numLayers > 1 + layersToSkip){
P1 = thisComp.layer(1).position;
P2 = thisComp.layer(thisComp.numLayers – layersToSkip).position;
P1 + (P2 – P1) * (index – 1) / (thisComp.numLayers – 1 – layersToSkip)
}else{
value
}

Dan

[Mike Clasby]

Thanks mucho.

[Mike Clasby]

Works a charm, but to get audio to drive the end layer, I changed it’s expression to this:

layersToSkip = 2;
temp = thisComp.layer(“Audio Amplitude”).effect(“Both Channels”)(“Slider”)*10
if (thisComp.numLayers > 1 + layersToSkip){
P1 = thisComp.layer(1).position;
P2 = thisComp.layer(thisComp.numLayers – layersToSkip).position + [temp, temp];
P1 + (P2 – P1) * (index – 1) / (thisComp.numLayers – 1 – layersToSkip)
}else{
value
}

Line 2 and the P2 line are hacked.

Thanks again.