houseplan-card/docs/ISOMETRIC.md

Isometric (2.5D) View internals

Issue #89 started a presentation-only volumetric View experiment; the normative Stage 1 contract is docs/specs/089-isometric-view-stage1.md, the fixed rendering decisions are in docs/adr/089-isometric-stage1-renderer.md. Since Stage 6 (#649) the 2.5D View is a public mode, see Stage 6.

Activation

One installation-wide setting, settings.volumetric_view: boolean, switched in General settings › Display › Show the plan in 2.5D (third item after «Show live presence on the plan»). It is stored only when true; missing or false means Flat, which is also the rollback. The rule is one for the card, the sidebar page and the kiosk: the View is 2.5D when the setting is on and Flat otherwise. Editors and houseplan-space-card are always Flat.

Saving the setting switches the View at once, without a reload, and the view centre is carried over through the logical plan (#583 §6.3). The lazy iso-scene-render graph is loaded only while the setting is on. The fingerprint fallback (#89) is unchanged: a failed scene falls back to Flat for that key.

On a cold dashboard load, the first visible successful frame is already 2.5D: the existing neutral House Plan loading surface remains above the plan until both the lazy graph and the paper-dependent floor classification are ready. This is the same in the ordinary card and kiosk mode. A real lazy-load failure releases that surface and uses the existing safe Flat fallback; it does not change the saved setting. Flat View and every editor do not wait for the 2.5D runtime. Paper colour is resolved after the DOM commit (white for a drawn plan, the theme card background under an image plan) and the resulting light-floor set is reused until the paper, resolved room fills or room membership changes (#654).

There is no toggle on the card and no alpha entry: iso is gone from LABS_FLAGS, the header projection-toggle and the phone-menu item projection (#616) are removed, and the former per-device, per-space choice houseplan_card_view_v1 is no longer read (owner decision: not migrated). The hp_alpha switch itself remains as a mechanism without experiments.

Coordinate systems

• Plan points are the existing 1000-unit logical floor coordinates.
• Scene points are coordinates in the effective SVG viewBox.
• HTML devices, vacuum pucks, room labels/cards and lock markers stay screen-facing. Their anchors use the same projectPlanPoint() snapshot as the SVG floor.
• clientToScenePoint() maps a client point to the current scene; floor hit testing then uses unprojectFloorPoint().

The current Stage 4 presentation uses a fixed orthographic affine camera:

rotDeg=0, tiltDeg=20, xyScale=1, zScale=1, origin=[500,500]
wallHeight=84 scale-aware visual units

There is no perspective, free rotation or user tilt. Switching projections preserves scalar zoom and converts the view centre through logical floor space. projectedFrame() includes both floor corners and wall-top corners so fit/home cannot clip the volume.

Room fit (#152) projects every final floor vertex at floor and floor-edge depth and every selected-room boundary-wall vertex at floor and wall-top height before building the AABB. It never projects a plan-space bounding rectangle, so a concave room does not gain fictitious corners. The resulting camera still uses the shared View controller; changing projection cancels the room-focus intent.

Geometry and composition

src/iso-projection.ts owns pure projection math. src/iso-walls.ts consumes the canonical wallBodiesGeometry() MultiPolygon after openings and extra physical bodies have been resolved. It normalizes outer/hole winding, builds one evenodd top path and at most one visible side per ring edge, then uses a stable depth/order tie-break. Complexity is O(E) in canonical ring edges.

For connected drafts and partitions those extras already contain computed bounded junction patches. Isometric wall tops/sides therefore use the same seamless L/T footprint as flat full/static cards; raw per-record rectangles are reserved for editor identity and never projected as competing wall faces.

The content fingerprint includes rooms, wall geometry/thickness, open cuts, openings, partitions, drafts, columns, scale/grid inputs, camera, wall height and algorithm version. It deliberately excludes _cfgEpoch, HA state, hover and show_borders. The per-card LRU is capped at eight scenes. Pan, zoom and HA-only updates reuse it.

Composition remains SVG-first:

1. the existing floor SVG and all its current live layers;
2. explicit visible wall sides and wall top;
3. screen-facing HTML overlays.

The floor keeps the same nodes and order for paper/backdrop, room fills/hover, Glow/spill, sun, decor/furniture, flat stair symbols, opening symbols and vacuum path/outline. Stage 1 does not add a second light source/layer. Markers and room cards intentionally remain above walls without geometric occlusion.

Failure boundary

Projection/topology failures latch flat fallback for the current space|fingerprint. One diagnostic is emitted without config, entity ids or URL data. The saved iso preference is retained; an explicit iso request retries the fingerprint, and changed geometry receives a new fingerprint. Flat rendering is the rollback path and does not depend on the iso cache.

Deliberate Stage 1 limits

• door, window and gate keep their current floor-plane symbol and live state;
• no vertical leaf/window panels, sill model or new window light;
• no floor-edge extrusion, shadows, photorealistic materials or marker occlusion;
• no volumetric editor and no volumetric houseplan-space-card;
• no YAML/config option or public settings surface.

Golden references are accepted only from the complete reviewed Linux artifact. The full large-house-isometric-v1 performance comparison is also canonical on the exact Linux CI SHA.

Stage 2 composition (#122)

Historical: written while 2.5D was a hidden hp_alpha experiment. Since #649 it is public; activation is described in Activation.

Stage 2 evolves the same hidden iso experiment; it does not add a flag, setting or public activation path. The accepted implementation contract is docs/specs/122-isometric-stage2.md and the fixed composition decisions are in docs/adr/122-isometric-stage2-composition.md. Its historical per-feature lifetime was superseded by the single indefinite hp_alpha gate in #448; the Stage 2 rendering contract itself is unchanged.

One structural scene, live opening leaves

The per-card LRU remains capped at eight entries. Its Stage 2 value contains:

• canonical wall top/sides and the physical-wall contact path;
• a room/exterior floor footprint and its low visible outer faces;
• immutable opening jamb/axis bases, including type, flips and selected wall face;
• the shared projected frame, including wall/opening tops and the low floor edge.

The key includes rooms, masonry/opening geometry, flips, scale/camera, wall and edge heights and algorithm revision. It excludes HA state, theme, hover, day/night and filter capability. openingAmount() is applied only after an LRU hit by projectIsoOpening(), so a contact update projects O(O) leaves without repeating a wall or floor boolean operation.

floorFootprintGeometry() deliberately accepts no independent physical-body input. The slab is the union of room floors and derived exterior masonry: internal room boundaries and nested holes make no decorative step, detached room components keep separate outside edges, while partitions and columns do not enlarge it.

Layer order and materials

All geometry roots use one scene viewBox. The existing floor/live nodes are grouped under the Stage 1 affine matrix; HTML anchors still use projectPlanPoint().

stage background
→ shared ambient shadow + low exterior floor edge
→ existing floor SVG (paper/image, room fills/hover, decor, Glow, sun)
→ canonical wall sides/top + inert vertical opening panels
→ existing HTML devices, labels/cards, locks and vacuum overlays

Wall top and side use two shared matte gradients. One shared filter supplies only the soft exterior ambient shadow of the complete building footprint; internal wall-contact and opening-leaf shadows are deliberately absent. Definition count is constant per card, never per face or opening. Forced colours use solid Canvas/CanvasText faces and omit decoration. A runtime without the required filter paint keeps solid structure, floor edge and vertical panels but emits no ambient shadow; this does not enter the structural fallback latch.

Vertical openings and display settings

src/iso-openings.ts mirrors the existing opening-symbol transform algebra: door has one jamb-hinged leaf, gate has two leaves with the established 0–10° exterior-face turn, and window has two light neutral casements. A saved passage keeps the same full-height masonry cut but has zero leaves/panels. Heights are fixed presentation ratios of ISO_WALL_HEIGHT; there is no schema field. The saved opening axis and Flat symbol remain on their canonical centreline. Derived 2.5D door/gate leaves pivot on the selected physical host face so their prisms do not start inside masonry; windows remain centred across the reveal. flip_v selects/determines the physical face and opening direction without changing saved coordinates. Jamb/cut depth remains physical and independent of the Flat symbol. Panels are pointer- and ARIA-inert. Existing lock badges/cards and HA actions remain the only interactive opening surface.

• borders visible: vertical panels replace the floor-plane symbols;
• hide_openings: true: panels disappear, while masonry cuts, Glow/sun and contact/lock meaning remain;
• show_borders: false: Stage 2 roots are absent and the established floor symbols and Stage 1 projected frame return (subject to hide_openings), avoiding floating panels or an invisible Stage 2 bound that reframes them;
• Flat, editors and houseplan-space-card retain their old symbols and DOM.

Stage 2 adds no window beam, Glow source, sun renderer, material config, network request or HA service path. Structural topology/projection exceptions still use the Stage 1 latched Flat fallback. The known independent exact-SHA view-toggle performance debt remains tracked in #124; #122 neither weakens its budget nor treats fallback as benchmark success.

Stage 4 visual handoff (#570)

Historical: written while 2.5D was a hidden hp_alpha experiment. Since #649 it is public; activation is described in Activation.

Stage 4 refines the same hidden iso presentation behind hp_alpha; it adds no public switch, configuration field or experiment id. Stage 3 history remains in docs/specs/160-isometric-stage3.md and docs/adr/160-isometric-stage3-overlays.md; the current acceptance contract is the reviewed specification in issue #570 plus its revision-3 designer handoff.

Camera and low screen-facing overlays

The camera is orthographic rotDeg=0, tiltDeg=20, with the same [500,500] pivot and scale-aware 84-unit wall height. Floor SVG, wall/opening projection, inverse hit mapping, invisible collision footprints and fit bounds share that one affine authority.

Device markers, room labels/cards and opening-lock badges keep their canonical floor anchors but render on a low plane four visual units above the floor. Devices and lock badges in the same room whose canonical reference-fit bounds (expanded by 12 CSS px) connect form one rigid cluster. Every member receives the same scene-space displacement, so pairwise vectors, rows and intervals are the affine projection of the Flat layout rather than a per-marker fan toward a room safe point. Room labels never enter a cluster and stay below interactive roots.

The reference-fit view, not the current live view, converts CSS safety values into scene units. Wheel/button zoom, pinch and pan therefore transform an already resolved scene and cannot invalidate placement. Structural changes — stage/camera, walls, rooms, marker membership or canonical anchors — rebuild it deterministically; viewport movement and HA-only state do not. One common vector clears the exact wall silhouettes and already placed clusters within an absolute 48 CSS-pixel reference-fit budget, using stable size/required-shift/ kind-id order and boundary candidates instead of scanning the displacement disk. The correction is runtime-only and is never written to configuration.

If no completely legal common vector exists, the nearest deterministic result keeps the cluster rigid and prioritises room ownership, then wall clearance, then overlap with an earlier cluster. It never splits or shrinks a cluster; residual overlap is an explicit degraded diagnostic. This supersedes the old single-marker fallback while retaining the 48 px cap. The two full isometric profiles keep the ordinary 150/60/75 ms resize/pan/state noise allowances (#585, #651). Fit probes reserve the maximum correction but do not execute live collision search. There is no painted plate, long tether, ground dot or per-marker shadow. The original screen-facing HTML root remains the only hit, focus, tooltip and action target, and selection/hover cannot invalidate the placement cache. Vacuum, Glow/spill, SUN, room fills/hover, arbitrary decor, furniture/backdrop, stairs and every persisted coordinate remain on z=0.

Room names remain screen-facing and lose stroke, text shadow, drop shadow and halo. Iso uses #303936 on a light presentation and #f2f0e8 on a dark one; contrast comes from colour and the bounded position correction, never an outline.

Openings, occlusion and materials

Door leaves turn by 50° × openingAmount, paired window leaves by 65° × openingAmount, and gates retain their established 0–10° behaviour. The same canonical flips/host face that drive the floor symbol determine hinges and direction; missing, unknown or unavailable state keeps the existing static-plan fallback. Opening geometry stays inert and lock actions stay on the existing guarded lock badge/card.

For wall height H, the fixed window frame spans 0.38H..1.00H, its sash 0.40H..0.98H, and clear glass 0.45H..0.93H; frame/sash rails are 0.05H. Frames and sill are neutral, glass side is #c9e4f3 and its top face is #e3f2fa. Fixed and live faces remain in buildIsoWallDepthQueue(). The slots belonging to one opening are resolved by physical camera depth, so raised glass covers the rear sill and rotating door/gate prism faces retain their physical order without reordering unrelated walls or openings. Door/gate faces use fill differences instead of strokes; window frame/glass borders remain.

The constant material/filter set remains theme-aware and bounded. Only the building ambient shadow remains; wall-contact and leaf shadows are omitted. Forced colours or missing filter support remove texture and the ambient shadow, not geometry, ownership or actions. show_borders:false is the exact no-volume branch: the floor keeps the real 0°/20° affine matrix and interactive overlays return to their floor anchors. hide_openings removes vertical decoration but preserves cuts, Glow/SUN and lock semantics.

The eight-entry structural LRU fingerprints the 0°/20°/84 profile, opening policy revision 3 and structural algorithm 5. It excludes HA state, live opening amount, hover/selection, theme, SUN and filter capability. The lazy iso-scene-render graph is still not requested with alpha off; topology, projection or module mismatch still enters the established fingerprint-latched Flat fallback. Linux exact-SHA goldens and performance profiles remain the canonical release evidence.

Stage 6: public mode, tiles, sun and materials (#649)

The visual language and the numbers come from the designer lab (sketch 07, attachments 09–13 of #649); the lab's code, coordinates and ids are not carried over. Lab units are converted into two bases:

• D — the base marker core diameter of the space (--device-base-size) already × ISO_ICON_SCALE = 1.12; the lab disc is 80 units.
• H — the 2.5D wall height (gridVisualUnits(ISO_WALL_HEIGHT, cellCm)); the lab wall is 218.8 units.

Everything below applies only to .stage.projection-iso.mode-view; Flat is byte-for-byte unchanged. Side-by-side acceptance frames: docs/design/649-25d-stage6/ACCEPTANCE.md.

Raised tiles (src/iso-tiles.ts, src/styles/iso-tiles.styles.ts)

• Every marker body (core, value pill, lock core) is a rounded rectangle with radius min(0.275 D, 0.3·h); the ring is not drawn (virtual markers too).
• A solid edge 0.1 D straight down, the body colour through brightness(.7) saturate(.85) (brightness(.82) saturate(.8) on a light floor); bodies with luma < 70 → #5b5e5a, white and dark bodies in the dark theme → #4a4a4a. The colours are evaluated once in TypeScript (isoEdgeColor) and emitted as a generated state table.
• Marker and lock are 1.12 × Flat; layout and collisions (iso-scene-render) use the same factor. The whole marker is lifted 0.075 D.
• One floor-shadow layer .iso-tile-shadows inside .devlayer, rendered after the markers in DOM order but with z-index: -1 (.devlayer is a stacking context), so no shadow ever lands on a neighbour's tile. Each marker and lock has an inert twin (data-shadow-of, aria-hidden, no pointer events) painted only as its inset, blurred box-shadow. Offset, blur and opacity follow the theme × floor table of the ТЗ (isoTileShadow).
• Light or dark floor is decided per room: the room fill at its opacity over the plan paper, luma > 0.55 is light (isoLightFloorRooms). A marker belongs to the room of its overlay owner or, without walls, to the room under it.
• A raised room label keeps its 44 × 44 px touch floor in an invisible ::before, like door locks; the label box itself is sized by its text, so the metrics row keeps the Flat distance from the name at every zoom (#665).
• Hover / focus-visible / selected / alert frames hug tile and edge (bbox + 0.075 D per side, + edge height) and float with the tile: #0C82F0, #0C82F0, #F0A00C, #F0410C, priority Alert > Focus > Selected > Hover. The body is not repainted on hover.
• forced-colors: active or no filter support: no edge and no shadow; size, tiles and frames stay.

Soft sun wash (src/iso-sun.ts)

In 2.5D the Flat wedges of sun_rays are replaced by a soft wash; the gates are the Flat ones (sun_rays, north_deg, sun.sun, elevation ≥ 3°, fade, no light in editors or at night) and so are the windows (windowLit()). Details: docs/SUN.md § 2.5D.

Walls, openings and labels (src/iso-materials.ts)

• The top face is the user's fill_colors.wall_fill.c, opaque (the Flat opacity does not apply to the prism), gradient to c × 0.93; the side face is c × 0.77 → × 0.68 @0.58 → × 0.60. The stage carries them as --iso-top-hi/lo and --iso-side-hi/mid/lo.
• The theme never repaints walls, openings, the floor edge, the texture or room labels: the theme-dark and prefers-color-scheme: dark rules for .iso-* are gone. Room labels use the Flat label colour. The building ambient shadow on the card background may follow the theme.
• Furniture keeps its Flat line width: stroke px = width × the plan screen scale in both views (the former iso constant 1 made it thicker).