user4426: I've made a series of comps each representing a letter from the alphabet.
Is there an expression or plugin where I can convert the relevant text character on screen to be replaced by the appropriate comp.
e.g. I've made a.jpg b.jpg c.jpg.
I type "abc" into a text field, apply a magic expression/plugin, and the letters abc are overlaid/replaced by my comps?
I'm not expecting perfect kerning, spacing etc.. Just a quick way to get a start on this.

user3161: The Characteristic plugin for After Effects is built specifically for this:
https://aescripts.com/characteristic/
You can set  kerning and spacing parameters for each character. Check out this tutorial to see how the font is set up:
https://vimeo.com/72438545
I hope this helps your situation!

4426: <p>I've made a series of comps each representing a letter from the alphabet.
Is there an expression or plugin where I can convert the relevant text character on screen to be replaced by the appropriate comp.</p>

<p>e.g. I've made a.jpg b.jpg c.jpg.</p>

<p>I type "abc" into a text field, apply a magic expression/plugin, and the letters abc are overlaid/replaced by my comps?</p>

<p>I'm not expecting perfect kerning, spacing etc.. Just a quick way to get a start on this.</p>
 3161: <p>The Characteristic plugin for After Effects is built specifically for this:</p>

<p><a href="https://aescripts.com/characteristic/" rel="nofollow noreferrer">https://aescripts.com/characteristic/</a></p>

<p>You can set  kerning and spacing parameters for each character. Check out this tutorial to see how the font is set up:</p>

<p><a href="https://vimeo.com/72438545" rel="nofollow noreferrer">https://vimeo.com/72438545</a></p>

<p>I hope this helps your situation!</p>
