# After Effects — Key Terms & Concepts ### Definitions and brief overviews for Adobe After Effects 2025 (and later) A reference glossary for the course, grouped by topic area. Where a recent release (2023–2025) changed how a feature works, that's noted. Items marked **(curriculum note)** clarify a term as it was used in the course materials. --- ## Foundations & Animation Mechanics **Projects** — A project (`.aep`) is the master file that holds everything: your imported footage references, compositions, solids, and settings. It doesn't contain the media itself, only links to it plus all the work you've built, so keeping source files organized matters. One project can contain many compositions. **Interface** — The arrangement of panels you work in: Project, Composition (viewer), Timeline, Tools, Effects & Presets, and others, saved as a Workspace. You can switch or customize Workspaces (e.g., Standard, Animation, Color) for different tasks. AE 2023+ also includes a contextual **Properties panel** that surfaces the selected layer's most-used controls in one place. **Compositions** — A "comp" is a container with its own frame size, frame rate, and duration where layers are stacked and animated over time. It's the equivalent of a scene or a timeline; the first comp in each course project is named **Main**. Comps can be nested inside other comps. **Solids and masks** — A *solid* is a full-frame layer of a single color (Layer ▸ New ▸ Solid), used for backgrounds, as a carrier for effects, or as a base for masks and shapes. A *mask* is a vector path drawn on a layer that defines which parts of that layer are visible. Together they're a common way to build simple graphic elements without external art. **Properties** — The adjustable attributes of a layer shown in the timeline: the five Transform properties plus any masks, effects, text, and material options. Almost every property can be keyframed or driven by an expression. Press shortcut keys (P, S, R, T, U) to reveal them quickly. **Transforms** — The five core spatial/visual properties every layer has: Anchor Point, Position, Scale, Rotation, and Opacity. They define where a layer sits, how big it is, how it's rotated, and how transparent it is, and they're the foundation of most animation. **Keyframes** — Markers that record a property's value at a specific point in time; with two or more, After Effects interpolates the values in between to create motion. They're the basic unit of animation. You set them with the property's stopwatch. **RAM / Playback Preview** — After Effects renders frames into memory (RAM) so a comp can play back smoothly in real time; the green bar under the timeline shows cached frames. Press the spacebar (or 0 on the numeric keypad) to preview. What used to be called "RAM Preview" is now just **Preview**. **Easy Ease** — A one-click way (F9) to smooth a keyframe's velocity so motion accelerates in and decelerates out instead of starting and stopping abruptly. Variants include Easy Ease In and Easy Ease Out. It's the fastest path to natural-feeling movement before fine-tuning in the Graph Editor. **Graph Editor** — A view that shows your animation as editable curves rather than keyframe dots, letting you precisely shape how a value changes over time. It's where you refine easing, fix mechanical motion, and craft custom acceleration. Toggle it with the graph icon in the timeline. **Value graph vs. Speed graph** — The *Value graph* plots a property's actual value over time (useful for single-dimension properties like Opacity or Rotation). The *Speed graph* plots the rate of change—how fast the value is moving—and is what After Effects shows by default for spatial properties like Position. You shape easing by dragging the bezier handles on whichever graph is appropriate. **Color keyframes** — Keyframes set on a color property (a solid's color, a shape fill, a Lumetri parameter) so the color animates over time. After Effects interpolates across the color values between them. Useful for shifting moods, day-to-night transitions, or branded color changes. **Spatial interpolation** — How After Effects interpolates a layer's *path through space* between Position keyframes—i.e., the shape of the motion path (linear corners vs. smooth bezier curves). You adjust it by editing the path's handles in the Composition panel or via Keyframe Interpolation. **Temporal interpolation** — How After Effects interpolates the *timing/velocity* between keyframes—linear, eased (bezier), or hold. It controls the feel of the motion (constant vs. accelerating) independent of the spatial path. Easy Ease and the Graph Editor both edit temporal interpolation. **Motion paths in Comp view** — The dotted trajectory shown in the Composition panel that represents a layer's movement between Position keyframes. Each dot is a frame, so closely spaced dots mean slow motion and widely spaced dots mean fast motion. You can drag keyframe points and bezier handles directly on this path. **Animation principles** — The classic principles of movement (anticipation, follow-through and overlapping action, ease in/out, squash and stretch, arcs, secondary action) that make motion feel believable. They're applied in After Effects through keyframe timing, easing, and the Graph Editor. The course uses them to turn mechanical moves into appealing ones. --- ## Text & Typography **Character panel** — The panel for formatting selected text: font family, weight, size, tracking, kerning, leading, fill and stroke color. It's the type-level control center for a text layer. **Paragraph panel** — The panel that controls text alignment (left/center/right/justified), indents, and space before/after paragraphs. It governs how lines and blocks of text are arranged. **Source Text** — The actual characters and formatting contained in a text layer, available as an animatable property. Keyframing Source Text creates hold (step) keyframes that swap the words at set times, and it can also be driven by expressions (for counters, live data, etc.). **Simple reveals** *(curriculum note)* — In the course this refers to introducing a title with basic Transform keyframes—typically Opacity 0→100 combined with a short Position slide (and sometimes Scale), eased with F9. It's the "no-animator" way to bring text on screen, taught before per-character Text Animators (Exercise 3, "Title Reveal"). Contrast with the mask- and animator-based reveals below. **Animation presets** — Saved combinations of effects and/or keyframes (`.ffx` files) that you apply from the Effects & Presets panel to reproduce a look instantly, including the many built-in **Text** presets (fades, typewriters, fly-ons). You can also save your own. Browsing them is also where Adobe Bridge comes in. **Animators** — Text Animators are special property groups added to a text layer (Animate ▸ Position/Scale/Opacity/etc.) that, combined with a Range Selector, animate the characters of that layer. They're how you build kinetic typography without keyframing each letter. **Range sliders / Range Selector** — The Range Selector inside a Text Animator defines *which* characters the animator affects, via its Start, End, and Offset values (the "sliders"). Animating the Offset sweeps the effect across the word; Advanced options (Shape, Ease High/Low) refine how it ramps. It's the engine of per-character text animation. **Per-character animation in the Range Selector** — Using the Range Selector's Offset (and Advanced shaping) so each character animates in sequence rather than all at once, producing staggered, cascading text motion. Raising the Ease High/Low values smooths the hand-off between characters. **Timing to audio waveforms** — Revealing a layer's audio waveform in the timeline (select the audio layer and press LL) so you can see beats and transients, then placing keyframes on them so visuals hit on the beat. You can also use Keyframe Assistant ▸ Convert Audio to Keyframes to generate amplitude keyframes that drive animation. **Revealing text with masks** *(curriculum note)* — In the course this is the "Write-On Reveal" technique (Exercise 6): you draw a mask on the text layer and keyframe its **Mask Path** so the word wipes on, optionally feathering the edge. A related variant uses Effect ▸ Generate ▸ Stroke (with "Paint on Transparent") along a mask path for a hand-drawn write-on. It reveals existing text rather than animating the characters themselves. --- ## Masking & Reveals **Pen Tool** — The tool for drawing custom bezier paths point by point, used to create masks on a layer or paths on a shape layer. Clicking makes corner points; click-dragging makes smooth curved points. It's the precision tool for cutting out arbitrary shapes. **Masks (Shapes, Modes, Properties)** — A mask is a path that limits where a layer is visible. *Shapes* can be preset (rectangle/ellipse) or custom (Pen). *Modes* (Add, Subtract, Intersect, Difference, etc.) control how multiple masks on the same layer combine. *Properties* are Mask Path, Mask Feather, Mask Opacity, and Mask Expansion. **Keyframe Mask Paths** — Animating the Mask Path property so the mask's shape or position changes over time, which is the basis of wipe-on reveals and shape morphs. Because the whole path is one property, the number and order of points should stay consistent between keyframes for clean interpolation. **Mask Reveals** — Using an animated mask to progressively show (or hide) a layer—e.g., expanding a mask to uncover an image, or sliding a rectangular mask across a title. It's a non-destructive reveal that doesn't alter the underlying layer. **Text Write-On Effects** — Making text appear as though it's being drawn or typed on, achieved either by animating a mask that uncovers the text, by the Stroke effect tracing a mask path, or by a typewriter Text Animator. The course treats this as a creative cousin of mask reveals. **Combining Multiple Masks** — Placing several masks on one layer and using their Modes to build complex visibility (e.g., Add two shapes, then Subtract a third). Each mask also has its own feather, opacity, and expansion, so combinations can be both crisp and soft. --- ## Color Correction & Grading **Lumetri Color** — After Effects' primary color effect, organized into sections: Basic Correction, Creative (looks/LUTs), Curves, Color Wheels, HSL Secondary, and Vignette. It's used both to *correct* (neutralize and balance) and to *grade* (stylize). Pair it with Lumetri Scopes to judge levels objectively. **Adjustment Layers** — Invisible utility layers that apply any effects placed on them to every layer beneath them in the stack. They let you grade or affect many layers at once, non-destructively. (See also "Adjustment Layers as comp tools" below.) **Levels & Curves** — Tonal-adjustment effects. *Levels* remaps input black/white/gamma to output values per channel; *Curves* gives freeform control over the tonal response by bending a curve. Both are core tools for fixing contrast and color casts. **White Balance** — Neutralizing unwanted color casts so whites read as white, controlled by Temperature (blue↔yellow) and Tint (green↔magenta), often set with Lumetri's WB eyedropper on a neutral area. Correct white balance is the usual first step before grading. **Exposure** — The overall brightness of the image. Adjusting it shifts the whole tonal range up or down; in Lumetri it's a Basic Correction slider read against the Waveform scope to avoid clipping highlights or crushing shadows. **Contrast** — The spread between the darkest and lightest tones. Increasing it deepens shadows and brightens highlights for more "punch"; decreasing it flattens the image. It's balanced alongside Exposure during correction. **Look Development** — The creative stage of deciding and building a shot's stylized appearance ("the look")—color palette, mood, contrast character—usually in Lumetri's Creative section with Looks/LUTs and Color Wheels. It comes after technical correction. **HSL Color (HSL Secondary)** — Isolating a specific range of Hue, Saturation, and Luminance to adjust just that color (e.g., shift only the sky or a shirt) without affecting the rest of the frame. Refining the key (denoise/blur) keeps the secondary adjustment clean. **LUTs (Look-Up Tables)** — Files that map input colors to output colors. *Technical* LUTs convert footage from one color space to another (e.g., log to Rec.709); *creative* LUTs apply a stylized grade. They're loaded in Lumetri's Creative or Basic sections. **Matching Shots** — Adjusting multiple clips so they look consistent in white balance, exposure, contrast, and color, often by copying a correction between them and fine-tuning against the scopes. Essential whenever a sequence intercuts different sources. **Vignettes** — A gradual darkening (or lightening) toward the frame edges that draws the viewer's eye to the center. Lumetri includes a Vignette section with amount, midpoint, roundness, and feather. Subtlety is usually the goal. --- ## Compositing & Keying **Blend Modes** — Math-based rules for how a layer's pixels combine with the layers beneath it (Screen and Add drop blacks; Multiply drops whites; Overlay/Soft Light add contrast). They're central to compositing light, textures, and effects. Set them in the timeline's Mode column. **Layer Order** — The top-to-bottom stacking of layers, which determines what's drawn in front and how blend modes and mattes resolve. Reordering layers changes the composite. It's the most basic compositing control. **Pre-comps** — A composition nested inside another comp, created by selecting layers and choosing Pre-compose. It groups elements so you can animate, effect, or reuse them as a single unit and keep complex projects organized. Over-nesting can slow previews, so use it deliberately. **Adjustment Layers as comp tools** *(curriculum note)* — Beyond grading, the course uses adjustment layers as general compositing tools: applying an effect (glow, blur, grade) to *everything* below at once, unifying separate elements into one cohesive image, and—because you can mask an adjustment layer—localizing an effect to just part of the frame. Toggling one off is also a quick before/after check that a composite reads as a single image. **Integrating Light + Glow Elements** — Selling a composite by adding atmospheric light: light leaks, lens flares, and the Glow effect (Stylize ▸ Glow), usually set to Screen or Add so the blacks disappear. Matching the light direction and color across elements is what makes them feel like one scene. **Green Screen key with Keylight** — Removing a green/blue background using Effect ▸ Keying ▸ Keylight (1.2): sample the screen color with the eyedropper, then judge the result in the "Screen Matte" view. It's the standard chroma-key workflow in After Effects. **Spill Suppression** — Removing the green/blue light that bounces onto the edges and surfaces of a keyed subject. Keylight has built-in despill, and the Advanced Spill Suppressor effect can clean up what remains. Without it, subjects look unnaturally green-fringed. **Edge Refinement** — Tightening a matte's edges so they're neither chewed-up nor haloed—done with Keylight's Clip Black/Clip White, screen softness/shrink-grow, and choke controls (or the Refine Matte tools). Good edges are what separate a believable key from an obvious one. **Light Wrap** — A subtle technique where the background's light/color is wrapped around the edges of the foreground subject, so the subject appears lit by and embedded in the new scene rather than pasted on top. It's usually built from a blurred, masked copy of the background composited over the subject's edges. **Contact Shadows** — A fabricated shadow placed where a subject meets a surface (e.g., feet on the ground) to "ground" them in the plate. Often made by duplicating the subject, filling it black, distorting/blurring it, and lowering opacity. It cues the eye that the element belongs in the scene. --- ## Track Mattes & Mattes **Alpha & Luma Mattes** — A matte uses one layer to define the transparency of another. An *alpha matte* uses the matte layer's transparency (its shape/text outline); a *luma matte* uses the matte layer's brightness (bright = visible, dark = transparent). Both have "inverted" variants. **Track Mattes** — Assigning one layer to act as the matte for another. **2023+ note:** the workflow was modernized—you set a layer's matte in the timeline's *Track Matte* column and link it to *any* layer with the matte pick-whip (it no longer must sit directly above), and the matte layer's visibility is switched off automatically with a toggle you can flip back on. Conceptually it's still "this layer's alpha or luma controls that layer's transparency." **Shape, Mask, and Text Mattes** *(curriculum note)* — This describes the three common kinds of matte *layer*: a **shape** layer (e.g., an ellipse) used as a clean geometric matte, a layer carrying a **mask** for a custom cut-out, or a **text** layer so footage/fill shows only inside the letters. Each is just a different source for the alpha used by the track matte. **Footage Inside Type Titles** — Using a text layer as an alpha matte so a video clip plays *inside* the letterforms. Animating the text (scale/position) carries the footage with it. A staple "filled type" title effect. **Animated Mattes** — Keyframing the matte layer—its position, scale, or mask path—so the revealed region moves or changes over time. This turns a static cut-out into a dynamic wipe or reveal. **Stacking Mattes** — Applying more than one matte to the same content, typically by pre-composing a matted pair and then applying a second matte to that pre-comp. It lets you combine, say, a text matte and a separate wipe. **Pre-comp Mattes** — Pre-composing so a matte applies to a whole *group* of layers at once, or so a single matte can be reused cleanly. Grouping the fill and matte into a pre-comp also keeps the track-matte relationship tidy when you move things around. **When to use the Set Matte effect** — Effect ▸ Channel ▸ Set Matte takes another layer's channel (e.g., its alpha or luma) as a matte *without* requiring the matte to be the adjacent layer. Reach for it when one matte must drive several layers, or when stacking order makes a normal track matte impractical—at the cost of being slightly less intuitive than a track matte. --- ## 3D, Tracking & Stabilization **Enabling 3D** — Turning on a layer's 3D switch, which adds Z-axis Position, three-axis Rotation/Orientation, and Material Options so the layer can live in 3D space with cameras and lights. **2024+ note:** the Advanced 3D renderer, true 3D model import (GLB/glTF), and environment/image-based lighting expand what 3D layers can do; Classic 3D remains for simpler card-based scenes. **Track Position / Scale / Rotation** — Motion tracking can solve and reapply different transforms: a single track point yields Position; two points yield Position + Scale + Rotation; four points yield a corner-pin. You choose what to track based on how the element needs to follow the shot. **Applying Track to a Layer** — After analyzing a track, you use the Tracker panel's "Edit Target" to choose the layer (often a null) that receives the data, then click Apply so that layer inherits the motion. Other elements are then parented to that target so they ride along. **Warp Stabilization** — The Warp Stabilizer effect (Distort ▸ Warp Stabilizer) analyzes footage and automatically smooths out camera shake, with controls for Smoothness and method (e.g., Subspace Warp). Over-smoothing can introduce warping/wobble, so it's dialed back to taste. **3D Camera Tracker** — An effect (Perspective ▸ 3D Camera Tracker) that analyzes a moving 2D shot and solves a virtual 3D camera plus a point cloud, letting you attach text or 3D elements that lock convincingly into the scene as the camera moves. It's the match-moving workhorse for handheld/parallax shots. **Planar Tracking with Mocha** — Mocha (bundled with After Effects) tracks flat *surfaces/planes* rather than single points, which is robust for screen replacements, corner-pins, and roto on signs, walls, and devices. Its tracking data is pasted back to a layer as a transform or corner-pin. **Attaching an object to a track** — Linking an element to tracked data—usually by parenting it (or its position) to the null that received the track—so it follows the tracked feature through the shot. This is how a graphic "sticks" to a moving surface. --- ## Rotoscoping **Roto Brush 2** — A semi-automatic rotoscoping tool, powered by Adobe Sensei AI, that isolates a moving subject from its background after you paint a few strokes. Introduced in After Effects 2020 and the current version since, it's dramatically faster and cleaner than manual roto for most shots. You work on it in the Layer panel. **Selection Propagation** — After you define the subject on one frame, Roto Brush *propagates* that selection forward (and backward) across frames, tracking the matte over time. You step through and add small corrective strokes wherever the edge drifts. **Refine Edge (Hair + Motion Blur)** — The Refine Edge tool, brushed along tricky borders, captures fine or soft detail—flyaway hair, fur, and motion-blurred edges—that a hard matte would clip. It produces a more natural, believable cut-out. **Freeze the Matte** — Committing/caching the finished Roto Brush result so After Effects stops recalculating it, which locks your work and speeds up the project. You re-freeze if you make further changes. **Frame-by-frame Mask Roto** — Hand-rotoscoping by drawing a mask and keyframing its Mask Path across frames to follow a subject—the manual, fully controllable alternative to Roto Brush. It's labor-intensive but precise, useful where AI selection struggles. **Mocha Planar Roto** — Using Mocha's planar tracking to drive rotoscoping splines, so a tracked surface carries the roto shape and you keyframe far less by hand. Efficient for roto on relatively flat, consistently moving regions. **Placing an element behind the subject** — Using a roto matte to slot a new element (graphic, text, effect) *between* the background and the isolated subject, so the subject appears to pass in front of it. It's a common payoff of a clean roto. --- ## Expressions **Expression basics** — Expressions are small snippets of JavaScript attached to a property (Alt/Option-click the stopwatch) that calculate its value automatically instead of, or on top of, keyframes. They're used to automate, link, and procedurally drive animation. Red error text usually means a typo, a wrong (case-sensitive) name, or a missing semicolon. **Pick-whip** — The spiral icon you drag from one property to another to automatically write an expression linking them, so the first property follows the second. It's the no-code way to create most property links. **`wiggle()`** — A built-in function, `wiggle(frequency, amplitude)`, that adds smooth pseudo-random motion to a property—e.g., `wiggle(2,30)` jitters twice per second by up to 30 units. It's the go-to for handheld jitter, idle motion, and organic randomness. **`loopOut()`** — A function that repeats a property's existing keyframes after the last one, with types like `"cycle"` (repeat), `"pingpong"` (bounce back and forth), `"continue"` (keep going at the last velocity), and `"offset"` (stack each repeat). `loopIn()` does the same before the first keyframe. **Time** — The global `time` value is the current composition time in seconds, often used to drive continuous, keyframe-free motion—e.g., `time*60` rotates a layer 60° per second. It's the basis of many procedural animations. **Linking Properties** — Connecting one property to another (within or across layers) via the pick-whip or written expressions, so changing the source automatically updates the linked property. It keeps related elements in sync and is the foundation of rigs. **Production-ready Expressions** *(curriculum note)* — In the course this means the small set of robust, reusable expressions used in real work rather than one-off experiments: inertial **bounce** (overshoot-and-settle), **auto-fade** (opacity driven by a control), **counters** (animated numbers via Source Text), responsive boxes that resize to text, and time-based loops. They're typically sourced from Adobe's Expression Examples and reusable rig setups, and are written to be commented and reusable. **Combining Expression and Keyframes** — Keyframing the base motion of a property and then adding an expression *on top* (for example, keyframed position plus `loopOut()` to repeat it, or a keyframed move plus `wiggle()` for added life). The expression evaluates using the keyframed value as its input, giving you authored timing with procedural enhancement. --- *Notes on versions: definitions reflect After Effects 2025 and later. The two areas most changed by recent releases are the **track-matte workflow** (modernized in the 2023 release—mattes are now linked to any layer via the Track Matte column) and **3D** (the 2024 release added the Advanced 3D renderer, real 3D model import, and environment lighting). Core concepts—keyframes, masks, expressions, color, keying, tracking, roto—are stable across these versions.*