Use markers to control camera position?

[Dan Ebberts]

Something like this should work:


widePos = [200,100,0];
johnPos = [100,200,0];
justinPos = [300,200,0];

C = thisComp;
n = 0;
if (C.marker.numKeys > 0){
n = C.marker.nearestKey(time).index;
if (C.marker.key(n).time > time){
n--;
}
}
if (n > 0){
if (C.marker.key(n).comment.toLowerCase() == "wide"){
widePos;
}else if(C.marker.key(n).comment.toLowerCase() == "john"){
johnPos;
}else if(C.marker.key(n).comment.toLowerCase() == "justin"){
justinPos;
}else{
value;
}
}else{
value;
}


Dan

[Zoe Woodworth]

Woo hoo! Thank you Dan! You have no idea how much easier that makes my life :).

[Zoe Woodworth]

Follow-up question: Could this be done with layer markers, instead of composition markers? Could the expression refer to such-and-such layer’s markers?

[Dan Ebberts]

Sure. The simplest way would probably just be to change this:

C = thisComp;

to this:

C = thisComp.layer(“your layer”);

If it were me, I’d probably also change the variable name to “L” (because it now represents a layer instead of a comp) and change “C.” to “L.” everywhere in the expression.

Dan

[Dan Ebberts]

Yes, the expression goes on the camera’s position property. I’ve cleaned it up a little:

Pos01 = [200,100,0];
Pos02 = [100,200,0];
Pos03 = [300,200,0];
m = thisComp.marker;
n = 0;
if (m.numKeys > 0){
  n = m.nearestKey(time).index;
  if (m.key(n).time > time) n--;
}
if (n > 0){
  if (m.key(n).comment == "Pos01"){
    Pos01;
  }else if(m.key(n).comment == "Pos02"){
    Pos02;
  }else if(m.key(n).comment == "Pos03"){
    Pos03;
  }else{
    value;
  }
}else{
  value;
}

[Dan Ebberts]

Something like this, maybe:

Pos01 = [200,100,0];
Pos02 = [100,200,0];
Pos03 = [300,200,0];
moveTime = 0.3;
m = thisComp.marker;
n = 0;
if (m.numKeys > 0){
  n = m.nearestKey(time).index;
  if (m.key(n).time > time) n--;
}
if (n > 0){
  t1 = m.key(n).time;
  t2 = t1 + moveTime;
  if (m.key(n).comment == "Pos01"){
    ease(time,t1,t2,valueAtTime(t1),Pos01);
  }else if(m.key(n).comment == "Pos02"){
    ease(time,t1,t2,Pos01,Pos02);
  }else if(m.key(n).comment == "Pos03"){
    ease(time,t1,t2,Pos02,Pos03);
  }else{
    value;
  }
}else{
  value;
}

[Dan Ebberts]

<div>A couple of small changes should keep it at “Start” initially:</div>

Pos0 = thisComp.layer("Start").transform.position;
Pos1 = thisComp.layer("Position 1").transform.position;
Pos2 = thisComp.layer("Position 2").transform.position;
Pos3 = thisComp.layer("Position 3").transform.position;
moveTime = effect("moveTime")("Slider");
m = thisComp.marker;
n = 0;
if (m.numKeys > 0){
  n = m.nearestKey(time).index;
  if (m.key(n).time > time) n--;
}
if (n > 0){
  t1 = m.key(n).time;
  t2 = t1 + moveTime;
  if (m.key(n).comment == "Start"){
    Pos0;
  }else if(m.key(n).comment == "Pos1"){
    ease(time,t1,t2,Pos0,Pos1);
  }else if(m.key(n).comment == "Pos2"){
    ease(time,t1,t2,Pos1,Pos2);
  }else if(m.key(n).comment == "Pos3"){
    ease(time,t1,t2,Pos2,Pos3);
  }else{
    Pos3;
  }
}else{
  Pos0;
}

As far as easing goes the only control you currently have is the “move time” slider, unless you want to replace AE’s ease() with your own ease function, which wouldn’t be too hard–you could use one of the Penner eases, but you’d have to pick one.

[Dan Ebberts]

Actually, there is a way to double up on the built-in ease() that I forgot about. You can do something like this:

Pos0 = thisComp.layer("Start").transform.position;
Pos1 = thisComp.layer("Position 1").transform.position;
Pos2 = thisComp.layer("Position 2").transform.position;
Pos3 = thisComp.layer("Position 3").transform.position;
moveTime = effect("moveTime")("Slider");
m = thisComp.marker;
n = 0;
if (m.numKeys > 0){
  n = m.nearestKey(time).index;
  if (m.key(n).time > time) n--;
}
if (n > 0){
  t1 = m.key(n).time;
  t2 = t1 + moveTime;
  t = ease(time,t1,t2,0,1);
  if (m.key(n).comment == "Start"){
    Pos0;
  }else if(m.key(n).comment == "Pos1"){
    ease(t,Pos0,Pos1);
  }else if(m.key(n).comment == "Pos2"){
    ease(t,Pos1,Pos2);
  }else if(m.key(n).comment == "Pos3"){
    ease(t,Pos2,Pos3);
  }else{
    Pos3;
  }
}else{
  Pos0;
}

[Dan Ebberts]

No, that line just applies the regular ease to the range 0-1 as the time goes from t1 to t2. Then, later in the code, ease gets applied again. So there isn’t anything that controls the amount of ease, it just gets applied twice, essentially easing the ease. You could keep doing that, but at that point you might as well use one of the Penner extreme eases like quart, quint, or exponential.

[Dan Ebberts]

Like this, I guess:

function myEase(t,t1,t2,v1,v2){
  if(t <= t1)return v1;
  if(t >= t2)return v2;
  dtEase = t2 - t1;
  dvEase = v2 - v1;
  tEase = (t-t1)/dtEase;
  if(tEase < .5)
    return v1 + (dvEase/2)*Math.exp(10*(2*tEase-1));
  return v1 + dvEase*(1-Math.exp(10*(1-2*tEase))/2);
}
Pos0 = thisComp.layer("Start").transform.position;
Pos1 = thisComp.layer("Position 1").transform.position;
Pos2 = thisComp.layer("Position 2").transform.position;
Pos3 = thisComp.layer("Position 3").transform.position;
moveTime = effect("moveTime")("Slider");
m = thisComp.marker;
n = 0;
if (m.numKeys > 0){
  n = m.nearestKey(time).index;
  if (m.key(n).time > time) n--;
}
if (n > 0){
  t1 = m.key(n).time;
  t2 = t1 + moveTime;
  if (m.key(n).comment == "Start"){
    Pos0;
  }else if(m.key(n).comment == "Pos1"){
    myEase(time,t1,t2,Pos0,Pos1);
  }else if(m.key(n).comment == "Pos2"){
    myEase(time,t1,t2,Pos1,Pos2);
  }else if(m.key(n).comment == "Pos3"){
    myEase(time,t1,t2,Pos2,Pos3);
  }else{
    Pos3;
  }
}else{
  Pos0;
}