After Effects

After Effects is GUI software, so this skill delivers knowledge and ready-to-paste assets — expressions, rig setups, export checklists, diagnostic flows, naming schemes, and ExtendScript — rather than a rendered file. It is a hub covering four domains; route to the matching reference for depth and complete recipes.

Routing

The .jsx automation scripts live in scripts/.

Expressions & rigging

Expressions are JavaScript evaluated on the property they are pasted on; value is that property's value, time is comp time in seconds, and index, thisLayer, thisComp are in scope. An expression overrides keyframes unless it incorporates value.

wiggle(2, 30);            // 2 wiggles/sec, amplitude 30 (property units)
loopOut("cycle");         // repeat keyframed range forever; "pingpong" / "offset" / "continue"
seedRandom(index, true);  // stable-but-unique per layer (timeless) before random()/wiggle()
thisComp.layer("Lead").transform.position.valueAtTime(time - 0.2 * index);  // staggered echo

Inertial bounce (overshoot/settle after the last keyframe) and the full loop/wiggle/rigging set are in references/expressions.md.

Rig controllable motion: add a null with Slider / Checkbox / Color / Angle / Point control effects, then reference them and parent transforms to drive many layers from one.

ctrl = thisComp.layer("Controls");
amt  = ctrl.effect("Intensity")("Slider");   // Checkbox → 1/0, Color → [r,g,b,a]
value * amt;

Expose those controls via Window → Essential Graphics and Export Motion Graphics Template (.mogrt) for Premiere/AE editors.

Export recipes

Two engines, and choosing wrong is the root of most export confusion:

• Render Queue (RQ) — masters/intermediates: ProRes, image sequences, lossless, alpha.
• Adobe Media Encoder (AME) — delivery: H.264 MP4, H.265, social presets.

Since AE CC 2014/2015 the native H.264 output module was removed from the RQ — make MP4s in AME, not the RQ. H.264/MP4 cannot store alpha, so a transparent comp exported to H.264 always fills with black; that is the classic "black background" complaint and not a bug. For transparency use ProRes 4444, a PNG/TIFF sequence, or HEVC-alpha (Safari) + VP9/WebM-alpha (Chrome), with Output Module Channels: RGB + Alpha.

Quick targets: editor handoff → ProRes 422 HQ; master/grade or alpha → ProRes 4444; web/social/client → H.264 via AME, VBR 2-pass (~10–16 Mbps 1080p, ~35–45 Mbps 4K). Full matrix, social specs, and step-by-step alpha exports in references/export-recipes.md.

Performance triage

Work top-down by symptom, cheapest fix first, and stop when it clears. Most settings are in Edit > Preferences (Win) / After Effects > Settings (Mac).

• Slow previews: Half/Third resolution → enable Multi-Frame Rendering → raise RAM allocation (leave ~6 GB for OS) → Adaptive fast previews → purge cache → Disk Cache on SSD/NVMe → solo heavy layers/effects → HW-accelerated decode → proxy heavy comps.
• Slow renders: confirm MFR on → RQ for masters / AME for delivery → HW decode H.264 → pre-render slow precomps → cheaper effects → transcode long-GOP to ProRes.
• Crashes/freezes: purge + empty disk cache → update NVIDIA Studio (not Game-Ready) drivers → reset prefs (Ctrl/Cmd+Alt+Shift on launch) → pull third-party plugins → free disk space → disable MFR if MFR-specific → roll back AE after a bad update.

MFR needs several GB RAM per active core. Ordered flows, exact preference paths, and the proxy workflow are in references/performance-triage.md.

Project hygiene

Keep projects organized, portable, and automatable.

• Folders: numeric-prefixed bins (01_Comps, 02_Precomps, 03_Footage, …, 99_Old) for stable sort order.
• Naming: PROJECT_section_descriptor_v01; precomps PRE_; rename solids/nulls to their role (CTRL_master); no spaces/special chars for farm/cross-OS safety.
• Broken links: AE references footage by path, so moving files breaks links. Double-click a missing item → Replace Footage > File and AE relinks the whole folder at once; enumerate with File > Dependencies > Find Missing Footage. Always hand off projects via File > Dependencies > Collect Files, never a bare .aep.
• ExtendScript (.jsx): wrap batches in app.beginUndoGroup(...) / app.endUndoGroup(); apply effects by matchName (e.g. "ADBE Gaussian Blur 2"), not the display name. Ready scripts: scripts/batch-rename.jsx, scripts/sequential-offset.jsx, scripts/apply-effect-to-layers.jsx.

Full naming scheme, label-color system, relink/Collect-Files/Reduce workflows, and scripting setup in references/project-hygiene.md.

Reference files

• references/expressions.md — expressions, rigging, MOGRT, Lottie/Media Encoder basics.
• references/expression-library.md — deeper expression cookbook: tuned inertial bounce, all loop variants, advanced wiggle, valueAtTime echoes, seedRandom grids, full rigging + coordinate spaces, MOGRT and Lottie/Bodymovin steps, Media Encoder presets.
• references/export-recipes.md — full codec/alpha/bitrate matrix, per-platform social specs, step-by-step transparency exports, AME preset cautions.
• references/performance-triage.md — ordered preview/render/crash flows, preference paths and values, MFR/GPU/disk-cache tuning, pre-render & proxy workflow.
• references/project-hygiene.md — folder template, naming and label systems, relink/Collect Files/Reduce details, scripting setup.
• scripts/batch-rename.jsx, scripts/sequential-offset.jsx, scripts/apply-effect-to-layers.jsx — ExtendScript automations.</content>