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so easy I could cry – shift position
I just want to shift a layer’s x position by 60 pixels in a loop. Everytime the loop fires (say every 15 frames), the layer’s x would be + 60.
also it would be great if the first fire was AT the 15th frame – i.e. the loop wouldn’t start until frame 15…
My forte is actionscript, my noobiness at AE expressions is killing me.
Thanks so much for any help on this…
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5 Replies
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This hack seems to do what you want. Put this expression on Position:
if (n == 0){
value;
}else{
xMoveAmount = 60;
moveFrames = 0;
holdFrames = 15;
f = Math.round(time/thisComp.frameDuration);
period = Math.floor(f / (moveFrames + holdFrames))
phase = f%(moveFrames + holdFrames);
x = xMoveAmount* period + linear(phase,0,moveFrames,0,xMoveAmount)value + [x,0,0]
This is a hack from a Dan expression, with “value +” added so you can just place you layer anywhere you want to start and it will go from there. If you change “moveFrames” to, say 5, the move will take 5 frames then hold for the remaining 10 frames. Here’s the original Dan post (’twas for rotation):
https://forums.creativecow.net/readpost/227/6860
To get it to start at frame 15, I’m using this expression so a marker triggers the above expression.
n = 0;
if (marker.numKeys > 0){
n = marker.nearestKey(time).index;
if (marker.key(n).time > time){
n–;
}
}if (n == 0){
value;
}else{//your expression here
}
So place a Marker at frame 15 (select layer, hit * (asterisk) on the nemric pad). The whole expression is:
n = 0;
if (marker.numKeys > 0){
n = marker.nearestKey(time).index;
if (marker.key(n).time > time){
n–;
}
}if (n == 0){
value;
}else{xMoveAmount = 60;
moveFrames = 0;
holdFrames = 15;
f = Math.round(time/thisComp.frameDuration);
period = Math.floor(f / (moveFrames + holdFrames))
phase = f%(moveFrames + holdFrames);
x = xMoveAmount* period + linear(phase,0,moveFrames,0,xMoveAmount)value + [x,0,0]
}
Dan probably has a cleaner way to do this, but I love to hack, so I did.
To find out about Loop expressions (loops keyframes), see this (Intro comp has examples of the different loops):
https://library.creativecow.net/articles/ebberts_dan/layer_looping.php
Since you know code, Dan’s site should be a God-send, here:
Also an older but great beginning site is here:
https://www.jjgifford.com/expressions/
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Thanks so much for your reply.
I plugged the code in but got the error “Class ‘global’ has no property or method named ‘n'”… I should have mentioned that I’m on AE 6. Would that have any impact on the code?
I’m going to check out those links you posted now, thanks again.
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Using the link you posted for the original rotation code, I think I’m on the right track with this:
shiftAmount = 60
movingFrames = 1;
holdFrames = 30;
f = Math.round(time/thisComp.frameDuration);
period = Math.floor(f / (movingFrames + holdFrames))
phase = f%(movingFrames + holdFrames);
[shiftAmount * period + linear(phase,0,movingFrames,0,shiftAmount),85]However, I have a feeling there’s a lot of redundant code?Namely period & phase, since my usage doesn’t involve rotation? Would you know how to streamline this?
My second question is how can I get the layer to start back at zero after it has moved 600px (ten loops)?
Thanks for the help!
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Okay… I think I got it…
shiftAmount = 60;
holdFrames = 30;
f = Math.round(time/thisComp.frameDuration);
period = Math.floor(f / holdFrames);
[(shiftAmount * period)%600,position[1]];If there’s any additional streamlining that can be made, or a simpler method please let me know…
Thanks for the help!
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“Looks good to me”, said Dr Franken-yikes as he examines a new specimen.
OK, too wierd.
I like your version of the expression.
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