Motion Decision Tree

Primary role: motion selection workflow.

Repository Boundary

Use this route to decide whether a product interaction needs motion and which behavior contract to write. Layout continues to own final geometry, semantic order, and scrolling. This route selects a responsibility, not a timing preset.

Reusable Method

1. Write the before and after state without animation. If either is unusable, fix that state first.
2. Name the information motion would add: acknowledgement, continuity, progress, or guidance. If none is needed, use an immediate update.
3. Choose the first matching responsibility below; compose only when one transition has multiple explicit jobs.
4. Complete the Motion Brief, including interruption and a reduced-motion path.
5. Use an Interaction Recipe and verify through the Review Workflow.

Selection Table

Observed task	Choose	Failure to prevent	First verification
Explain an already rendered effect	Vocabulary	Inferring an API from appearance	Exact, ambiguous, and unknown observations
Acknowledge a command	Action feedback	Decorative feedback mistaken for successful completion	Pending, success, failure, repeated activation
Show or hide supporting content	Disclosure	Hidden content retaining focus or delayed access to content	Keyboard activation and reversal
Enter or dismiss a modal task	Modal transition	Focus or input blocking tied to an animation timer	Focus entry, cancellation, return
Preserve identity when items move	Reorder and filter	Visual movement changing logical reading order	Stable identity and focused-item removal
Explain an operation that takes time	Progress and completion	An invented percentage or success before confirmation	Delayed result, cancellation, failure
Follow direct manipulation	Drag and settle	A cancelled gesture committing data	Release, reversal, cancellation, alternative input
Explore a product through scroll-controlled chapters	Scroll-driven story	Entry callbacks mistaken for continuous progress; inaccessible pinned content	Reverse, jump, middle reload, static reading
Navigate a whole page as fixed-viewport scenes	Full-viewport scene navigation	Gesture bursts skipping chapters; trapped input or lost history	Burst, boundary, direct link, Back, Escape, native copy scroll
Decorate an idle surface	Practice Reference	Repetition competing with the user's task	Compare against removal and reduced motion

Worked Selection

A search result list changes after a filter selection. The task is to understand which results remain; it is not to watch every row arrive. Choose reorder/filter only if stable result identities can be preserved. Keep the filter control focused. Announce the resulting count separately from any visual interpolation. When no results remain, present an actionable empty state immediately. If identity cannot be mapped reliably, replace the list without implying continuity.

The decision record is a proposal until tested on the consuming product. It does not establish that motion improves search comprehension.

Opinionated Guidance

Prefer one explanatory event over a sequence of unrelated effects. Evaluate high-frequency interactions with realistic repetition; a first-use recording can hide accumulated cost.

Platform-Specific Guidance

Choose implementation APIs only after the behavior contract. Native gestures, browser navigation, scroll timelines, and animation libraries have different cancellation and lifetime behavior. Platform adaptation starts at Platform Guides.

Unsupported Absolutes

An immediate update is a valid outcome. A recipe name does not imply a spring, compositor execution, fixed duration, or proven usability improvement.

Verification Contract

For the selected row, verify normal completion, interruption, repeated input, the reduced-motion path, and a failed or empty result where relevant. Record the actual outcome separately from the expected outcome. Revisit this route when a task cannot find a suitable contract or two recipes imply conflicting ownership.

Source, License, And Attribution

Locally authored selection workflow based on this domain's existing vocabulary and review contracts. No external code or expressive examples are adapted.

IA Navigation

Parent: Motion. Next: Motion Brief.