Connect animated shape layer to text box for lower third reveal

[jlhorst]

I designed the animation for a lower third template before adding in the expressions and have hit a block with finishing it out.

I have a bar that builds on the right and moves to the left, revealing two lines of lower third text as it goes. The two lines of text are linked to an optional background box who’s width is determined by the longest of the two text layers.

I want to tie the bar animation to furthest edge of the background box so that the bar reveals the text and optional background layer from their longest point when animating on. I want the bar to hit the same landing position every time. Right now, the bar animates on/from the same point.

The text/background reveal is currently tied to the bar layer. I've tried tying the bar position to the text layers like I did with the background box but can't figure out how to retain the animation/easing and the landing position. 

What would be the best way to finish this out so it works the way I want it to? What expressions should I use? Would a null object function better here?

Current bar starting point:

Static starting point

End result

Animation end result

Thank you!

[Roland Kahlenberg -]

The keyframe values for the animated bar MUST be linked via Expressions to the Right and Left edges of your text box. The sourceRectAtTime Expression Method is what you'll be looking at, to get at these values.

There have been a number of related Qs on this in the forum. I'm in a rush so please do a Forum Search -

[jlhorst]

Excellent, thanks!! I'll reply again if I'm not able to figure it out. Appreciate the fast reply!

[jlhorst]

Ok I'm giving up. I've searched the forum, read up on it and watched a ton of videos and feel like I'm missing something very obvious but I don't have enough experience with expressions to know what the missing piece actually is.

I understand how to use sourceRectAtTime to get the edges of a text or shape layer, but I'm still not sure how to link the keyframes I already have on the red bar to the width of the text. And rather than link the bar to the edge of the text layers, I'd prefer to link the bar to the background since the background is already responding to whichever line of text is longest - is that possible?

Thanks!

[Rick Gerard]

You can link any property you can keyframe to any other property you can keyframe with an expression. When you are talking shape layers there is a separate shape>transform option for every element in the shape layer. Tying these to the anchor point, position and scale of the whole layer is pretty easy to do once you understand the relationships.

To give you specific instructions we need to see your comp with the modified properties of all layers revealed and have a detailed explanation of how you want things to work. When I create MOGRT's that automatically position a background over a text layer I almost always reference the comp size and the text layer's anchor point and position. The only thing that can really foul up these calculations is the baseline shift in the Character panel. 

Show us your timeline and we can have a better idea of how to help you. From your description, I would think all you have to do is calculate the difference between the Transform Rectangle background and the Transform Rectangle>Red Bar and have the size of the rectangle BG drive the bar layer to the left corner of the background bar. 

[Roland Kahlenberg -]

If your background has keyframes, then you would use one of the Interpolation Methods (linear, ease ...) to link the bar's position to the background's existing keyframes.

If you're still stuck, then you should provide the Expression or KFs you are currently using for the background's animation. We can then show you how to use an Interpolation Method to link the two props.

[jlhorst]

Here is a screenshot of my current code. I went through lots of iterations based on what I've found online and this is the last attempt I've made. I had originally used the red bar ("Red Line 2") to drive the animation in the template but now have that done with a null object ("Reveal Keyframes"). "BG NEW" is the layer I want to link my red bar to so that it follows the width of the layer as driven by the text.

Thank you!

[Roland Kahlenberg -]

I'm providing an old AEP that I worked on a while ago -

http://www.broadcastGEMs.com/mediaServer01/bGEMs_Example_Basic_WipeScale_01.zip

I believe what you want to do has been setup in the AEP/Comp. The setup is similar to yours but mine uses an animated scale[0] of the the Background/Box. I then hook up the Bar's position to the animated scale with the Interpolation Method (linear, in my case). The Bar's position is derived from the Top Right and Top Left of the Box.

HTH

[jlhorst]

Thank you for sharing this! Unfortunately, when I go to download it, I get a file not found error. 😞 Do you have another way to share it?

[Roland Kahlenberg -]

Please try the download again.
I'm doing lots of housecleaning for the site and things are going to be moved and even deleted. So please download the file ASAP.

[jlhorst]

I’ve just tried to download the file again and am getting the same error. ☹

[Roland Kahlenberg -]

PM me your email address and I'll send you the AEP.

[jlhorst]

Will do, thank you!! Really appreciate it!

[Mathias Moehl]

Sounds like the perfect job for Pins & Boxes.

1. create pins and a box around your text

2. create a second box, set its options to render as a vertical line and set its X anchor to 0% such that you have a line at the left edge of the box. With the margin parameters you can offset the line as needed and with the offset controls you can animate it in easily (these are all parameters of Pins & Boxes Box rig).

In this example we create horizontal line, but vertical ones work in the same way