Wassim SAMADandClaude Opus 4.8
f0206dc6eb
The snapping model (Shift = cycle mode, Alt = force/free, mode-driven reads via isGridSnapActive/isMagneticSnapActive/isAngleSnapActive, snapProfile-declared context) lived only in code and the plan; tools.md still preached the legacy "Shift = bypass snapping". Close the drift so the architecture review refuses tool changes that revert to the old pattern: - tools.md: replace the held-Shift-bypass manipulation policy with the unified mode-driven model + the single snap read path. - interaction-scope.md: new "Snapping mode & modifiers" section (contexts, read path, modifiers, the chip-needs-a-scope rule) + a Rules bullet + the known-legacy MEP movers (migrate-on-touch) incl. the dual-path constraint (a bespoke mover must not open a `moving` scope — it re-mounts the generic mover via useMovingNode). - review-architecture skill: add interaction-scope.md to the reads and a new "F. Interaction scope, snapping & modifiers" checklist — new shiftKey-bypass, ungated grid step, missing snapProfile, a new useEditor interaction flag, or a bespoke mover opening a moving scope are blockers; touching the legacy MEP movers forces migration. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
176 lines
11 KiB
Markdown
176 lines
11 KiB
Markdown
# Interaction Scope
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*The authoritative interaction state machine ("the spine") — one scope describes "what the user is currently doing".*
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Applies to: `packages/editor/src/lib/interaction/**`, `packages/editor/src/store/use-interaction-scope.ts`.
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Before this, "what is the user doing right now?" was re-derived from 7+ independent
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`useEditor` flags (`movingNode`, `placementDragMode`, `activeHandleDrag`,
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`curvingWall`, `curvingFence`, `editingHole`, `movingWallEndpoint`,
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`movingFenceEndpoint`). Every overlay and pick site re-derived its behaviour from
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a different subset, so the flags could drift into illegal combinations (moving +
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curving at once; a stale `movingNode` after a drag ended). The scope collapses
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them into one discriminated union, making those combinations unrepresentable: a
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scope is exactly one interaction at a time, and `idle` carries no payload.
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---
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## The model
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`InteractionScope` (`lib/interaction/scope.ts`) is a discriminated union on `kind`:
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| `kind` | Payload | What |
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|---|---|---|
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| `idle` | — | Nothing in flight. The only state where selection/hover picking is meaningful. |
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| `placing` | `nodeId`, `nodeType`, `view`, `pressDrag` | Placing a fresh node (catalog/preset/build tool). `pressDrag` = gizmo press-drag (commit on release) vs click-to-place. |
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| `moving` | `nodeId`, `nodeType`, `view` | Moving an existing node. |
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| `handle-drag` | `nodeId`, `handle` | Dragging a resize/translate/rotate handle of a selected node. |
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| `drafting` | `tool` | Click-to-click drafting of a polyline/polygon kind (wall/fence/slab/…). |
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| `reshaping` | `nodeId`, `reshape`, `holeIndex?` | Reshaping a selected node's geometry. `reshape` is `curve \| hole \| endpoint \| boundary`. |
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| `box-select` | — | Marquee selection drag. |
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| `painting` | — | Material paint application. |
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`reshaping` groups endpoint/curve/hole/boundary edits as sub-states of one scope
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(rather than four sibling kinds) — there is one node and one in-flight reshape,
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so "curving and hole-editing at once" stays unrepresentable. `view` is `'2d' | '3d'`.
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### Helpers
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- `isIdle(scope)` / `isActive(scope)` — `idle` vs anything else (`ActiveInteractionScope`).
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- `scopeNodeId(scope)` — the node a scope acts on, or `null`. `drafting`/`box-select`/`painting`/`idle` target no single existing node.
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- `selectionEnabled(scope)` — true only while `idle`. During any active interaction the pointer belongs to that interaction's body, not to selecting a different object; the picking choke point must not route a hover/click to selection while this is false.
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---
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## The store contract
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`useInteractionScope` (default export of `store/use-interaction-scope.ts`) is the
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single owner. Exactly one scope at a time; the only writable shape is
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`InteractionScope`, so there is no setter that can leave a half-state.
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| Method | Behaviour |
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|---|---|
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| `begin(scope: ActiveInteractionScope)` | Enter an interaction. If one is already active it is replaced (single owner, no producer races). |
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| `update(patch)` | Patch the current scope's payload. **Ignored when idle, and ignored when the patch's `kind` differs from the active kind** — payload updates must not change which interaction is running (use `begin` for that). |
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| `end()` | Return to idle atomically. Both commit and cancel call it; the write-vs-revert distinction lives in the interaction body, not here. |
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| `endIf(match)` | Return to idle only if the active scope satisfies `match`. |
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**Atomic-end invariant.** `end()` sets the scope back to `IDLE_SCOPE` in one
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write — no interaction payload can leak past the end of its interaction (no stale
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`nodeId`, no half-cleared flags). `endIf` exists because scope is currently
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driven from independent legacy flag clears (below): clearing one flag (e.g. a
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fence curve) must not stomp an unrelated active scope (e.g. a wall move), so the
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clear only ends the scope if it owns it.
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---
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## Hot-set: what is raycast-eligible during an interaction
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`lib/interaction/hot-set.ts` answers "which scene objects can the active
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interaction target?" It is never hand-authored per interaction — it falls out of
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the node's `asset.attachTo` plus whether a candidate exposes a top surface.
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`attachClassOf(attachTo)` collapses attachment to three `AttachClass` values:
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- `wall` — `attachTo` of `wall` or `wall-side`.
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- `ceiling` — `attachTo` of `ceiling`.
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- `surface` — everything else ("floor item" really means *surface-resting*: rests on the floor **or** any host's top surface).
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`isPickableForAttach(placed, candidate)` decides, for a node of attach class
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`placed`, whether a `HotSetCandidate` is a valid host/surface:
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- `wall` → only `wall` candidates.
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- `ceiling` → only `ceiling` candidates.
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- `surface` → the floor (`isFloorLike`), or any candidate that `exposesTop` (registry `capabilities.surfaces.top`) — but **never** a ceiling-mounted host. A floor lamp must not land on a ceiling fan; a ceiling fan's `attachClass` is `ceiling` and is excluded as a host top (Track E).
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`isCandidateInHotSet(scope, placedAttachClass, candidate)` lifts this to a whole scope:
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- `idle` → `true` (selection/phase filtering stays in the selection manager; the hot-set only narrows what an *active* interaction can target).
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- `placing` / `moving` → `isPickableForAttach`, or `true` when `placedAttachClass` is `null`.
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- every other active scope → `false`: nothing in the scene is a placement target, so the interaction body's own raycast owns the pointer.
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`HotSetCandidate` (`type`, `isFloorLike`, `exposesTop`, `attachClass`) is derived
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from the candidate node + its registry definition by the caller, keeping this
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module pure and unit-testable without the scene or registry.
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---
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## Overlay policy: the scope matrix
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`resolveOverlayPolicy(scope)` (`lib/interaction/overlay-policy.ts`) returns the
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"Sims-light" overlay behaviour: default-off, opt-in for the active action. During
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any non-idle scope, scene objects stay visible but non-pickable, and DOM/HUD
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overlays step back differentiated by how distracting they are.
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| Overlay | Idle | Any active scope |
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|---|---|---|
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| Zone labels | shown | hidden (not a primary editing concern) |
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| Context badges (hover name pills) | shown | faded + `pointer-events: none` |
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| Conflicting controls (other objects' handles, floating action menu) | shown | hidden |
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| Scene objects pickable | yes | no (the hot-set owns targeting; context preserved, can't grab the wrong thing) |
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| Active affordances (ghost, snap guides, dimension labels, the active handle) | shown | shown |
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| Contextual control HUD interactive | yes | yes (it *is* the active interaction's own controls — exempt from the pointer-events step-back) |
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The policy is binary (`IDLE_POLICY` vs `ACTIVE_POLICY`) keyed on `isActive`.
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---
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## Snapping mode & modifiers (the unified model)
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Snapping is a persistent, **per-context**, always-visible mode — not a held-Shift bypass.
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The active scope selects the *context*; the context's current mode selects the *behaviour*.
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There is no per-kind snapping switch.
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- **Contexts** (`lib/snapping-mode.ts`, `SNAP_PROFILES`): `wall` (grid/lines/angles/off, default grid),
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`item` (lines/grid/off, default lines), `polygon` (grid/lines/off, default grid). A kind opts in by
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declaring `NodeDefinition.snapProfile` (`'item' | 'structural'`); `snapContextOf(scope × profile)` maps
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it — `structural` while **setting direction** (drafting / endpoint drag) → `wall` (angle-bearing),
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`structural` otherwise (translate / curve) → `polygon` (no angle), `item` → `item`. No profile → no chip.
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- **Single read path.** Tools read `isGridSnapActive()` / `isMagneticSnapActive()` / `isAngleSnapActive()`
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(`store/use-editor`); the grid step is `useEditor.getState().gridSnapStep` gated on `isGridSnapActive()`.
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These resolve the mode from the scope via `getActiveSnapContext()` → `snappingModeByContext[context]`.
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- **Modifiers.** Shift (tap) cycles the mode for the active context; Ctrl (tap) cycles the grid step;
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Alt (hold) is force / free (raw cursor + commit past invalid; for MEP runs, the vertical-riser carve-out).
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Shift is **not** a snap bypass and Alt is **not** a toggle.
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- **The chip is the scope's.** The contextual HUD shows the active context's mode and is the only place the
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mode is cycled — so a tool that wants its chip must run inside a scope whose `snapContextOf` resolves
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(a build tool, `drafting`, `placing`/`moving`, or `reshaping`).
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**Known-legacy (migrate on touch).** A few bespoke movers predate this model and still read
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`event.shiftKey` as a snap bypass with hardcoded steps: the MEP move/endpoint tools
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(`packages/nodes/src/{duct-segment,pipe-segment,liquid-line,lineset,duct-fitting}/{move-tool,selection}.tsx`),
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tracked in `plans/editor-placement-interaction-overhaul.md`. A PR that **touches** one must migrate it to
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the model above, not extend the legacy path. Note: opening a `moving` scope from a bespoke mover is **not**
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the migration — `useMovingNode()` reads the scope, so `tool-manager` re-mounts the generic
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`MoveRegistryNodeTool` alongside it (the dual-path FPS/teleport bug). Resolve the mode without a global
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`moving`/`reshaping` scope; see the plan's dual-path note.
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---
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## Migration status (strangler fig)
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The scope is the target source of truth, but the legacy `useEditor` flags still
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exist as a mirror and are being retired reader-by-reader. Today the scope is
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**driven from** the central `useEditor` setters — `setMovingNode`,
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`setActiveHandleDrag`, `setCurvingWall`/`setCurvingFence`, `setEditingHole`,
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`setMovingWallEndpoint`/`setMovingFenceEndpoint`, `setMode` (for painting) — and
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from the box-select tool. Each setter calls `begin`/`end` (and `endIf`, so an
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independent flag clear can't stomp an unrelated scope) to keep the scope in sync.
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**Contributors:**
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- Add a new interaction by calling `begin(...)` / `end()` on `useInteractionScope`, **not** by adding a new `useEditor` flag.
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- Read "what the user is doing" through the scope and its helpers (`isActive`, `scopeNodeId`, `selectionEnabled`), not by recombining flags. New readers should consume the scope so the legacy flag can be deleted once it has no readers.
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- Add a new attach behaviour by setting `attachTo` on the asset — the hot-set follows with zero per-kind wiring.
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---
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## Rules
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- **One owner, one scope.** Only `useInteractionScope` writes the scope, and only via `begin`/`update`/`end`/`endIf`. Never reconstruct interaction state from a private combination of flags.
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- **`end` is atomic and payload-free.** Never leave a `nodeId`/payload behind on idle; commit-vs-revert logic belongs in the interaction body before `end`.
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- **`update` cannot change `kind`.** Switching interactions is a `begin`, not a patch.
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- **Hot-set and overlay policy are pure derivations of the scope** (and, for the hot-set, the candidate metadata). Don't branch overlay/picking behaviour on legacy flags — branch on the scope.
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- **Don't add new `useEditor` interaction flags.** New interactions go through the scope.
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- **Snapping is mode-driven.** Read snap state through `isGridSnapActive` / `isMagneticSnapActive` / `isAngleSnapActive` (gate any grid step on the first); never bypass snapping via `event.shiftKey` / `modifiers.shiftKey`, and never hardcode an ungated grid step. Snappable kinds declare `snapProfile`. Shift cycles the mode; Alt is force/free.
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