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Possible to offset Expressions based on frames?
Hi! 🙂
I am working with PAL Compositions (25fps) in AE7 and wonder if it is possible to offset Expressions based on frames instead of time?
Example:
Layer 1 change its Opacity from 0 > 100 at frame 10
Layer 2’s opacity is driven with an Expression that has been pick whipped to Layer 1’s OpacitySo now Layer 1 and 2 changes its Opacity at the same time, frame 10, as expected.
But, if i want Layer 2 to change its Opacity from 0 > 100 at frame 11 i use the following Expression on Layer 2’s Opacity:
thisComp.layer(“footage.psd”).transform.opacity.valueAtTime(time – .04)My cuestion is if there is possible to use frames instead of time, ie 1 instead of .04?
AFAIK, Expressions never work on frame basis, only on time basis but wanted to ask here for an answer! 🙂
/Roger
Premiere Pro User Group Sweden – http://www.pproug.se
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6 Replies
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Sure, use thisComp.layer(“footage.psd”).transform.opacity.valueAtTime(framesToTime(1)) for instance. AE will do all the rest of the math itself.
Mylenium
[Pour Myl
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Mylenium, if i use that Expression and paste it to Layer 2 its Opacity changes 0 and stays there forever.
Do you have any clues to what i have done wrong?
/Roger
Premiere Pro User Group Sweden – http://www.pproug.se
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[Averdahl] “My cuestion is if there is possible to use frames instead of time, ie 1 instead of .04?
AFAIK, Expressions never work on frame basis, only on time basis but wanted to ask here for an answer! :)”
Time is always calculated on a decimal basis. If you wanted to work in terms of frames then it is very easy – just type, 1/25, if you wanted a 1-frame differential. And 7/25 if you wanted a 7-frame differential.
It’s actually a lot easier and it works for different people – there may be those that prefer to work with decimals/integers and there are those like yourselves who prefer to think in terms of frames.
HTH
Roland Kahlenberg
broadcastGEMs
customizable animated backdrops with Adobe After Effects project files -
Well, this is a static expression. You still need to add “time” as a driving factor:
thisComp.layer(“footage.psd”).transform.opacity.valueAtTime(time-framesToTime(11))
in that case you need to subtract everything to make the expression look backward. If your offset is supposed to be the same for all layers, you should automate a little
ref_offset=10;
ref_opa=thisComp.layer(“footage.psd”).opacitynew_opa=ref.opa.valueAtTime(time-framesToTime(ref_offset*index))
[new_opa]
With that you only need to clone your layer as often as you need.
Mylenium
[Pour Myl
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Thank you very much Mylenium! 🙂
It works like a charm and i am going to look into how to automate the Expression with the script you provided. I am new to Expressions so your help is very valuable for me! 🙂
/Roger
Premiere Pro User Group Sweden – http://www.pproug.se
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Thank you very much Roland! 🙂
It worked like a charm! I am new to Expressions so your help is very valuable to me!
/Roger
Premiere Pro User Group Sweden – http://www.pproug.se
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