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Question

Parent and Child Transform property linking

Forum|Forum|2 years ago
April 24, 2023
3 replies
4710 views

I want to connect several an objects to a null object and follow its movment. When I use the posioton pick whip, the child jumps to the parent's location.

How do I prevent this jump?

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Rick Gerard

Community Expert

I would use a completely different approach. It is much easier to get a predictable "text following a path" animation if you add a mask to a text layer and animate the First Margin. You can tie the motion path on one text layer to another and the text and any other properties you want to with simple pickwhip expressions.

I would start with a "Leader" text layer, add a Delay and a Fade Expression control Slider to the "Leader" Layer, then use the leader's index - the Follower layers index + a delay and an opacity fade expression to tie everything together.

Change the motion path of the "Leader Layer" or the keyframes, or even the Text and all other layers follow. No Pre-composing, no adding a bunch of typing to expressions on multiple layers, incredibly easy text editing, and the ability to animate the offset to produce a much more flexible comp and a much better design.

Here is the expression that delays the duplicate Follower layers:

ref = thisComp.layer("Leader");
fr = thisComp.frameDuration;
lyrCount = index - ref.index;
dly = ref.effect("Delay")("Slider")/100 * fr * lyrCount;
t = time - ref.inPoint;
src=ref.text.pathOption.firstMargin.valueAtTime(t - dly)

This is the expression for Opacity:

ref = thisComp.layer("Leader");
n = (index - ref.index);
f = 10 * ref.effect("Fade")("Slider") / n;

Every other expression in the comp is just a pickwhip drag from the Parent/Link column so changes in the Leader Layer are always reflected in the rest of the layers. You can stack as many text layers as you want, make each duplicate layer a different color, or even throw in a bunch of other effects to make something amazing in just a few minutes that takes only seconds to customize.

Project File included.

This gives you the ability to mimic echo but put a different color on each of the follower layers.

Follow_Me.zip

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TJPLewisAuthor

Participating Frequently

Rick, Thank you. These is a cool effect and I will use it. In my situation, I am trying to duplicate an effect created by a co-worker where the text flies in with a slinky effect so the letters spacing is wide while the word moves but when the first letter stops there is an increaing delay for each letter of the word after that to stop.

After batttling this for a week, cause I'm a stubor German, I asked the auther how he created the effect. I would have asked sooner but he does not work with Adobe software. In fact, he asked me to reformat a video from AVI to MP4 or H264. Imagine my suprise when he said he used Outlook. I pulled up a training video on Outlook Animation and was shocked what can be done with it. But that another story. Anyway, if After Effects can't do the slinky effect than I'm good. Time to move on. But, surely it can do it. I mean, it';s After Effects for Pete's sake. Thanks again Rick. I appreciate your time and guidance. Really, I do. Fromw what I can tell, noby writes expressions at Halliburton. The most they do is use the presets in the Effects drop down list, which I recently became aware of also. AS you can tell, I'm a newbie. Cheers

WellCare_Short.zip

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TJPLewisAuthor

Participating Frequently

However, I just noticed that you include a delay. So, this may answer my slinky effect question. Let me play with your script and learn.

Thanks

thepixelsmith

Community Expert

This kind of sounds like a job for parenting instead of property linking.

Parenting allows for the children layers to have realtive transform values while property linking (by default) sets the linked property to the same value as the parent.

Is there a reason parenting won't work for you?

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TJPLewisAuthor

Participating Frequently

In a nutshell, this is what I am trying to duplicate.

(329) Retro Time Delay Logo Animation | Adobe After Effects TUTORIAL - YouTube

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Rick Gerard

Community Expert

If you use an expression to tie properties together, they layer with the expression; the Child will inherit the same properties as the Parent layer. If you want add the values, all you have to do is add value + to thisComp.layer("Parent Layer"). position so it looks like this:

value + thisComp.layer("Parent Layer").position

If you want to compensate for the position of the "Parent" layer so the child layer does not move when you add the expression, you need to throw half the comp width and height into the mix like this:

compCenter = [thisComp.width/2, thisComp.height/2];
ref = thisComp.layer("Parent Layer").position;
compCenter - ref + value;

If the Child layer is actually parented to the Parent Layer, then the positions will remain relative to each other without any expressions. There is no need to add an expression to Position.

I'm not sure what you are trying to accomplish. Maybe a workflow or design goal explanation would help us help you.

I didn't test the second expression so there may be an initial jump in position.

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TJPLewisAuthor

Participating Frequently

Rick, Thank you for your reply. I will try your suggestions. Since my post, I moved all the anchor points to match the null objects anchor point. When I make a path for the Null Object, the letters move fine without stacking on top of the Null Object once I child them to the Null object.

However, I tried to add "ValueAtTime(-.1) and the letters no longer track the null object. I can set their position at the start and end of a time stamp, but they do not follow the Null's path once I hit Start.

I am trying to have a word fly into the screen with a delay between the letter and land.

Does this make sense? I am new to after Effects so I am learning the terms.

If you emial timothylewis8458@gmail.com, I will reply with my personal (rather than garbage) email address.

Thank you,

Tim Lewis

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TJPLewisAuthor

Participating Frequently

Rick, I added the "value + " to the front of the position expression and needed to adjust my letters. But it seems fine now. I tried to add the "ValueAtTime (-.1)" and I do not get an error but it does not work on screen or once rendered.

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