Motion design, defined

Name: Premation
Author: Premation

73 terms you will meet in any motion tool, each defined once and then shown where it lives in Premation.

2.5D: Flat layers arranged in three-dimensional space and seen through a camera. There are no modelled objects, but there is real perspective, parallax and depth of field.
Adjustment layer: A layer with no content of its own whose effects apply to everything rendered beneath it in the stack.
Alpha channel: A fourth channel stored beside red, green and blue that records how opaque each pixel is. It is what lets a graphic sit over other footage without a black box around it.
Anchor point: The origin a layer rotates and scales around. Moving it changes what a rotation pivots on without moving the layer itself.
Aspect ratio: The proportion of a frame's width to its height: 16:9 for landscape video, 9:16 for vertical, 1:1 for square.
Bézier curve: A curve defined by anchor points and the handles that pull it between them. The same mathematics draws vector paths and shapes the timing between keyframes.
Bitrate: The amount of data a video uses per second, usually in megabits. A higher bitrate means a larger file and fewer compression artefacts.
Blend mode: How a layer's pixels combine with what is already drawn beneath it: multiply darkens, screen lightens, difference inverts where they overlap.
Bone: One rigid segment of a skeleton. Bones chain into a hierarchy; rotating a parent rotates every child with it.
Camera tracking: Working out how the real camera moved through a shot from features tracked in the footage, so that 3D layers can be placed in the scene and stay put. Also called matchmoving or a 3D camera solve.
Chroma key: Removing a background of one colour, usually green or blue, so the subject can be placed over something else. Also called green screen or keying.
Codec: The method used to compress and decompress video or audio: H.264, HEVC, VP9, ProRes. The container, such as MP4 or MOV, is the file that holds the result.
Compositing: Combining several images into one picture: layers stacked with transparency, blend modes, mattes and effects. A compositor is a tool built around that.
Composition: A canvas with a size, frame rate, duration and background, plus the stack of layers drawn on it. The unit you animate in and export from.
Continuous rasterization: Redrawing vector artwork at whatever size it is scaled to, instead of drawing it once and enlarging the pixels. It keeps text and shapes sharp when they are scaled up.
Depth of field: The range of distances that appear sharp. Everything nearer or farther than the focus distance blurs, more with a wider aperture.
Dolly zoom: Moving the camera towards a subject while zooming out, or the reverse, so the subject stays the same size and the background appears to stretch or compress.
Easing: The rate at which a value travels between two keyframes. Linear is constant speed; an ease slows into or out of a keyframe, which is what makes motion read as physical.
Effect stack: The ordered list of effects applied to one layer. Order matters: a blur before a glow and a glow before a blur are different pictures.
Engine: The program that evaluates a project and draws its frames, as distinct from the interface you click. Some tools run it inside the interface process; others run it as a process of its own.
Expression: Code that computes a property's value every frame instead of reading it from keyframes. Wiggle, loops and links between properties are the classic uses.
Frame blending: Synthesising in-between frames when footage is slowed down or its frame rate does not match the composition, instead of duplicating or dropping frames.
Frame rate: How many frames are shown per second: 24 for film, 25 or 30 for broadcast and the web, 60 for smooth motion. It is set by the composition, not by the footage in it.
Graph editor: A view of animation as curves: value over time, or speed over time. Dragging the handles reshapes how a property moves between keyframes.
HDR10 and HLG: Two ways of encoding high-dynamic-range video. HDR10 uses the PQ transfer curve with static metadata; HLG uses a hybrid curve that also plays acceptably on standard displays.
Hold keyframe: A keyframe with no interpolation after it: the value stays fixed until the next keyframe, then jumps. Used for cuts, blinks and stepped motion.
IK and FK: Two ways to pose a chain of bones. Forward kinematics rotates each bone and the children follow. Inverse kinematics moves a target and the chain solves to reach it.
Image sequence: A video stored as one numbered image file per frame. It is larger than a movie file, but lossless, easy to resume and readable by any pipeline.
Keyframe: A recorded value at a point in time. Two keyframes and an interpolation between them are the whole basis of animation.
Kinetic typography: Text animated so that its movement carries meaning or rhythm: words that arrive with the voice, letters that scale, slide or scatter.
Layer: One element in a composition: a shape, text, image, video, audio clip, camera, light, null or nested composition, with its own transform and time span.
Layer style: A treatment that follows a layer's shape rather than its pixels: drop shadow, inner glow, bevel, satin, stroke. Photoshop's idea, borrowed by every motion tool.
Linear blend skinning: How a mesh follows a skeleton: every vertex takes a weighted mix of the transforms of the bones near it. The weights decide how smoothly a joint bends.
Lottie: A JSON animation format (bodymovin) that plays natively on the web, iOS and Android. Vector shapes and transforms travel; raster effects do not.
Lower third: A caption in the lower part of the frame that names a speaker or a place, usually a name and a role that animate in, hold and leave.
Mask: A vector path on a layer that limits what part of it is visible. Feather softens the edge; mask modes add, subtract and intersect several paths.
MOGRT: Motion Graphics Template: a composition with a few fields exposed so an editor can change the text or colours without opening the animation.
Motion blur: The streak a moving object leaves within a single frame, because a camera's shutter is open for a span of time. Adding it to animation makes fast movement read as smooth.
Motion path: The spatial trajectory an animated position follows, drawn as a line through its keyframes. Editing the path's Bézier handles changes the route without touching the timing.
Motion tracking: Following a feature in footage from frame to frame and writing its position as keyframes, so graphics can be attached to something that moves.
Native plugin: A plugin written in C or C++ and compiled to a shared library that the host application loads. It is the kind of plugin After Effects effects are.
Null object: An invisible layer with a full transform, used as a parent so a group of layers can be moved, rotated or scaled together.
Optical flow: An estimate of how every pixel moves from one frame to the next. It is the basis of synthesised slow motion, matte propagation and some kinds of tracking.
Parallax: Near objects appearing to move faster than far ones as the viewpoint moves. It is the main cue that makes a flat scene read as deep.
Parenting: Linking one layer's transform to another's so the child inherits the parent's position, rotation and scale, on top of its own.
Pick-whip: A drag gesture that links one thing to another: a layer to a parent, or a property to an expression that reads another property.
Planar tracking: Tracking a flat surface, such as a screen, a sign or a wall, instead of a single point, so a graphic can be pinned to it in perspective.
Pre-composition: A composition nested inside another as a single layer. Its layers render to their own buffer and composite as one unit, which is how complex scenes stay editable.
Premultiplied alpha: A way of storing transparency in which each pixel's colour has already been multiplied by its alpha. The alternative, straight alpha, keeps colour and alpha separate. Reading a file as the wrong one gives dark or bright fringes at the edges.
ProRes 4444: The Apple ProRes profile that keeps full colour resolution and adds an alpha channel. It is the usual format for handing a graphic with transparency to an editor.
Proxy: A smaller, easier-to-decode copy of a clip that stands in for the original while you work, so heavy footage plays and scrubs smoothly.
Puppet pin: A control point placed on a mesh generated over flat artwork. Dragging the pin deforms the artwork around it, so a drawing can bend without a skeleton.
Rack focus: Shifting focus from one subject to another during a shot, so that attention moves with the sharp area.
RAM preview: Rendering frames into memory once so they play back at full speed afterwards. It is After Effects' name for cached playback.
Range selector: The part of a text animator that decides which characters, words or lines an animation applies to. Animating the selector, not the property, is what makes text arrive letter by letter.
Render queue: A list of export jobs that render one after another, so several compositions, formats or sizes can be set up once and left to run.
Render snapshot: A flat, immutable description of one frame, produced by sampling every animated value at one time. Everything that draws reads from it, so preview and export cannot disagree.
Repeater: A shape operator that fans one shape into many copies, each offset by a transform, so a single dot becomes a ring, a grid or a spiral.
Rotoscoping: Cutting a subject out of footage frame by frame, by drawing or painting a matte around it. It is what you do when there is no green screen to key.
Shape layer: A layer made of vector paths with fills and strokes, plus a chain of operators that modify them. Resolution-independent and animatable down to the vertex.
Shutter angle: How long the shutter stays open during each frame, written as an angle. 180 degrees is half the frame's duration and is the film standard; a larger angle gives more motion blur.
Shy and solo: Two timeline switches that people confuse. Shy hides a layer from the timeline list without hiding it in the picture. Solo renders only the soloed layers.
Speed ramp: A smooth change in a clip's playback speed: slowing into a moment and speeding back out, rather than a hard cut to slow motion.
Stagger: Offsetting the same animation across several layers or letters so they move one after another instead of all at once.
SVG: Scalable Vector Graphics, the web's vector format. Paths, fills, strokes and groups in XML that any browser draws at any size.
Text animator: A set of property offsets applied to a text layer through a selector, so each glyph can move, fade, scale or rotate on its own schedule.
Time remapping: Keyframing a clip's internal time: which source frame plays at which composition frame. Freezes, reverses and ramps are all time-remap curves.
Timecode: A way of naming every frame as hours, minutes, seconds and frames, so that two people or two machines can refer to the same frame.
Track matte: Using one layer's luminance or alpha to decide another layer's transparency. A luma matte uses brightness; an alpha matte uses the shape.
Trim paths: A shape operator that reveals only part of a stroke, from a start to an end percentage. Animating End draws a line on; animating Offset chases a dash along it.
Two-node camera: A camera with a point of interest it always looks at. Move the camera and it keeps aiming at the subject; move the point and the camera turns to follow.
WebGPU and Dawn: WebGPU is a modern GPU programming interface with compute shaders, designed for browsers. Dawn is the open-source library, used by Chromium, that implements it on top of Direct3D 12, Metal and Vulkan.
Wiggle: Controlled randomness added to a property so that it shakes, drifts or jitters at a chosen frequency and amount. In After Effects it is the most used expression.