v0.145.4Internal beta docs
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Beta documentation · eXLib v0.145.4. Public release is pending.

Reuse an Expression Anywhere

The expression you wrote last month, working on today's project, without rewriting the layer names in it.

The task

  1. Keep the expression somewhere you can find it again.
  2. Find it later, by something other than remembering the file name.
  3. Apply it to a different rig — which means pointing it at this project's layers.
  4. Hand it to someone else.

How it goes in plain After Effects

  1. Save it as text, in a notes app or a .txt file beside the project. Finding it later means remembering what you called it.
  2. Or save an animation preset: select the property, Animation → Save Animation Preset…, and it writes a .ffx into AE's Presets folder. It comes back through the Effects & Presets panel, searchable by name.
  3. Re-point it by hand. A preset carries the expression text as written — every thisComp.layer("Ctrl") in it still names the layer from the project it came from, so applying it in a new project means editing those names in the expression field.
  4. Share by handing over the .ffx or the text.
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Both routes work. What neither does is re-connect the expression's layer references to the project it just landed in — that stays a manual edit, every time.

What changes with eXLib

The library is the place, and apply-time connection is the mechanism.

Saving:

  1. Save on the toolbar captures the editor — plus this session's variables and controls — as an Author draft.
  2. Give it a title, description and tags in Author; those are what search matches later.
  3. Choose a Publish target folder and Publish to library.

Finding:

  • Search matches title, description, tags and code — so "the one with the wiggle on scale" is findable even when you've forgotten its name.
  • Filter by folder, pack or tag, and narrow to what fits your current selection with the Selected property chip.

Applying into a different rig — the part plain AE leaves manual:

  • Every layer reference the expression needs can be a variable rather than hard-coded text. Wire it to Ask on apply and it is asked for at the moment you apply, not baked in.
  • When apply runs, a Connect variables panel lists exactly the rows that still need an answer, with a source picker per row and a live status as you fill them in. Answer them, press Apply, and eXLib splices the real references into the code for you.
  • How often you see that panel is a setting: Settings → Applying → Checking level — Guide me confirms every source on every apply, Errors only (the default) asks only about what would fail, Expert applies and reports afterwards, Leeroy Mode doesn't ask.
✓

A warning never blocks an apply — only a variable with nothing resolvable does. The panel counts warnings, states them in words, and leaves Apply enabled.

Sharing:

  • Settings → Backup & restore → Back up / export library… writes the whole library to one portable .exlib file; a folder row exports just that folder.
  • On the other machine, Import / restore archive… reads it back. Import is additive, and anything that collides is yours to resolve — Keep mine, Keep both, or Take theirs.

Step by step

Step In plain After Effects With eXLib
1. Store it A .txt beside the project, or Animation → Save Animation Preset… Save on the toolbar → an Author draft
2. Describe it The file name Title, description and tags in Author
3. File it A folder in Finder/Explorer, or AE's Presets folder Publish target folder → Publish to library
4. Find it again Remember the name; search Effects & Presets by name Search over title, description, tags and code; filter by folder, pack, tag, or the selected property
5. Apply it here Apply the preset, or paste the text onto the property The row's Apply action, against your live selection or the tab's pin
6. Point it at this project's layers Edit the layer names inside the expression, per reference Answer the Connect variables panel — pick the layers, eXLib writes the references
7. Create the controls it needs Add and name each Expression Control by hand Created by Apply, on the layer you chose
8. Keep the original safe Copy the file somewhere Every launch writes an automatic backup; the newest 30 are kept, each with Restore
9. Hand it to someone Send the .ffx or the text Back up / export library… → one .exlib; they Import / restore archive…