Start playing a pre-comp at a certain time

[rikil]

I have animation about 2 minutes long. It consists of 10 photo frames where each frame shows a simple animation. The camera moves from frame to frame and when the camera focuses on a frame, the animation is played for that frame. Is it possible to start playback of a pre-comp at a certain time in the main comp?

[Mylenium]

I suggest you read up on time-remapping and all that stuff in the online help if simply staggering the layers doesn't do it. Of course you're still gonna need extra keyframes and also account for the paly time in your camera movement.

Mylenium

[Rick Gerard]

Just drag the pre-comp forward or backward in the timeline. Pre-comps, or more accurately, nested compositions are just like footage. They have in point, out point, and duration. Where they are in the timeline determines when playback begins.

[rikil]

I was a little vague. The first frame should be visible at all times in each photo frame during the animation and then played at a certain time. If I move the animation along the timeline, they are not visible all the time.

[Dan Ebberts · Accepted solution]

I think you'd just turn on time remapping for the pre-comps and use a simple time remapping expression like this to start the playback at a specific time (at 3 seconds, in this example):

tStart = 3;
time - tStart;

The trick is figuring out how the expression knows it's time to start playback. You could use a layer marker, like this:

if (marker.numKeys > 0){
  tStart = marker.key(1).time;
  time - tStart;
}else
  0;

[rikil]

You are a hero! I put the second code in each pre-comp and a Labelmarker where I want the animation to start playing.

[Falk2000]

Genious, thanks a lot!

Is there a way to start the compostion all over again with a second and third and fourth marker?

[Dan Ebberts]

Try this:

t = 0;
m = marker;
if (m.numKeys > 0){
  n = m.nearestKey(time).index;
  if (time < m.key(n).time) n--;
  if (n > 0){
    t = time - m.key(n).time;
  }
}
t

[Falk2000]

that works, awesome! Thanks a million :))

[florian_8466]

@Dan Ebberts Dear Dan,
thank you for this wonderful expression. I'm trying to do the oposit (start at 0 and stop the animation of a precomp at a given marker). Is this possible? I really have no clue and I'm in research-mode since this morning.  Thanks in advance.

[Dan Ebberts]

I'm not sure exactly what behavior you want, but this example should play normally until the first marker, then freeze:

m = marker;
t = time;
if (m.numKeys > 0){
  t = Math.min(time,m.key(1).time);
}
t

[florian_8466]

thank you so much dan! this whichcraft is exactly what I meant. you helped me a lot with it. Much appreciated. I wish you a pleasent day.  

[florian_8466]

Dan, it's me again. I connected the number of the marker to a slider control, which works like a charm.

m = marker;
t = time;
if (m.numKeys > 0){
t = Math.min(time,m.key(thisComp.layer("Controller").effect("1")("Schieberegler")).time);
}
else 0;

Thank you a million times again.

Just out of curiosity... Let's say I want to start the animation at a certain marker and stop it at another certain marker with it's correnspondending contents in a precomposition (as example a counter from zero to nine and every marker number is representing the number in the precomposition at that time).

My approach was this (which you can guess is not working):

m = marker;
t = time;
startKey = thisComp.layer("Controller").effect("Start")("Schieberegler");
stopKey = thisComp.layer("Controller").effect("Stop")("Schieberegler");

if (m.numKeys > 0) {
startTime = m.key(startKey).time;
stopTime = m.key(stopKey).time;
if (t < startTime) {
t = startTime;
} else if (t > stopTime) {
t = stopTime;
}
}
t;

Where is my mistake? I just don't get it... This is just to much coding for me 😄

[Dan Ebberts]

Like this maybe:

m = marker;
t = time;
startKey = thisComp.layer("Controller").effect("Start")("Slider");
stopKey = thisComp.layer("Controller").effect("Stop")("Slider");
try{
  tStart = m.key(startKey).time;
  tStop = m.key(stopKey).time;
  t = linear(time,tStart,tStop,tStart,tStop);
}catch(e){
}
t