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Linking a null to a trim path.

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James TaylorLinking a null to a trim path.
by on Sep 15, 2013 at 4:29:54 pm

Hello!

First time posting, I normally work on 2D character animation but Im working on some video content to function as part of my friends photography exhibition.

My friend has been using an app to trace walks she goes on and im tracing over the route so that I can use trim paths to show the route forming and them key frame it depending on where she speeds up slows down etc.

To add a bit extra to this (it felt far to easy for her to be paying me for it!) I was going to have another video where I cut in close to the path so instead of the whole map forming you just following the tip of the line in close up as it trims along changing direction etc.

Figured I would do this by parenting a null to the point where the 'trimming' is occurring and then parent a camera to the null.

Sounds simple but I cant figure out a way of parenting a null to follow the growing end point of the line.
I could do this manually but the routes are really long and twisty, and if I could simply parent the null it would make it a lot easier if I have to change the timing of the trim.

Hope that makes sense and someone is able to help.

This forums always been an amazing resource for me so just to end with a big thank you for years of help.


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John CuevasRe: Linking a null to a trim path.
by on Sep 16, 2013 at 11:26:55 am

Twirl open the shape and drill down into mask. At this point you may want to check to make sure your first vertex is set to where you want the path/null to start from, if not right click the starting point and select Mask and Shape Path > Set First Vertex. Next, select and click the word "path" next to the stop watch(it should highlight) and copy the path(cntl+c). Select the null and open up the position parameter, select position and paste the path information. Your null should follow the path now.

Also this might come in handy. ReverseMaskPath Compatibility After Effects

Johnny Cuevas, Editor
Thinkck.com

"I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work."
---THOMAS EDISON on inventing the light bulb.


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James TaylorRe: Linking a null to a trim path.
by on Sep 16, 2013 at 3:47:17 pm

Hey John thanks for the reply. That has definitely got the null on the path! The other part to my original query was also about whether if you used 'trim paths' on a path if you could get a null to be parented to the trim itself.
Ie: if you moved the 'end' value of the trim the null will be moved with it.

Saying that Im wondering If I could parent some kind of mask to the null that covers all of the path in front, revealing the path behind.
Then I wouldn't need the trim. Messy, but it'll serve the purpose.

Thanks for you're help!!


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John CuevasRe: Linking a null to a trim path.
by on Sep 21, 2013 at 12:37:34 pm

Glad I was able to provide some assistance

Johnny Cuevas, Editor
Thinkck.com

"I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work."
---THOMAS EDISON on inventing the light bulb.


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Kevin FinneganRe: Linking a null to a trim path.
by on Feb 4, 2014 at 7:45:01 pm

I hope you've already figured this out but on your null's position, the pasting of path info from the clipboard creates a bunch of "roving through time" keyframes and two regular keyframes (start and end). Just position the starting and ending keyframes on the same frames as your trim paths starting and ending keyframes. This should match up the motions perfectly assuming you only two keyframes for trim. Then you can choose auto orient along path for your null for more rotational motion too! If anyone reads this, This only works if you have one path. I'm trying to extend this functionality to shape layers with multiple paths using trim-individual paths. Any ideas?


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