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moving an image over a path with looping

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Tom Sefton
moving an image over a path with looping
on Dec 3, 2013 at 12:09:27 pm


We are producing some films for an online security client that need to show how their products can protect a network from online threats.

We've designed some nice photoshop dots to look like colour coded network alerts which we need to animate around the network map (along straight lines and circles that make up the network) from each source back to the host machine. Is there a fast way of doing this with an expression for each single layer (there are 4 colour coded dots from each machine), or do I need to animate one dot over a period of time for each journey and then duplicate the effect on multiple duplicate pre-comped layers?

Cheers for any help...

Also posted to AE expressions forum.

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Joseph W. Bourke
Re: moving an image over a path with looping
on Dec 3, 2013 at 2:45:41 pm

Tom -

An easy method would be to simply use text on a path, using the period symbol for your dots (unless of course those Photoshop dots you refer to are customized). I use this all the time when I'm doing workflow diagrams for clients, and it seems to be the quickest solution. I often use square dots in my diagrams, but you can choose square or round periods, depending on the typeface you choose.

Joe Bourke
Owner/Creative Director
Bourke Media

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John Cuevas
Re: moving an image over a path with looping
on Dec 3, 2013 at 3:24:36 pm

Another method would be to use a shape layer to create your dots. Use a shape layer to create your path, and turn off fill. Open up stroke and press the "+" key by dashes to add a split in your stroke. Finally adjust your "Stroke Width", "Gap" and "Color" and you should be there.

Then with the add fly out, add a "Trim Paths" effect and you can build on your dots. By playing with the offset under the Dashes, you can even have the dots move.

Here's a quick example project:

Johnny Cuevas, Editor

"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 Camp
Re: moving an image over a path with looping
on Dec 3, 2013 at 6:41:38 pm

since had asked about an expression, the fast easy way with an expression would be to use the valueAtTime() function...

what you'd want to do is animate one of the layers the way you'd want it to move (i'll call it the 'leader'), then you use the expression to have the other layers follow the leader.

to make it easy have the follower layers ordered consecutively under the leader and then try an expression like this for each of the followers.

offset = .25; //value in seconds

the expression tells a layer to use the position of the layer above it back in time (.25 seconds in this case).

this may not be the best option for you... since the valueAtTime() function is time based, the spacing of the layer will vary based on the speed of the leader. a fast moving chain of layers will have a larger space than a slow moving chain, so if the speed of the leader changes the spacing will too...

some times that's good, some times not. i've used this to animate dots to represent traffic on a map, and it worked great. when traffic moved fast, the dots spaced out, then when it slowed, they all bunched together. but if i had needed the spacing to stay consistent, either of the other methods would have been better.

Kevin Camp
Senior Designer

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Tom Sefton
Re: moving an image over a path with looping
on Dec 3, 2013 at 10:18:26 pm

Thanks very much for all of your suggestions. The client is being very specific about the look of each individual element - even the dots have to look right! Hence them sending over an agreed photoshop file that I need to animate from.

Seems as though the best way to do it is having multiple instances of the layer and then have a mix of 2 suggestions. The expression is great for the representation of traffic at a steady speed, but when we want to accelerate, I'll dissolve to a faster version.


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