Spatial Design

Spatial Design (visionOS)

The design rules that make a visionOS app comfortable instead of exhausting — distilled from Apple's spatial-design sessions (WWDC23–26). Widget-specific rules live in visionos/widgets; custom immersive-environment production and budgets live in immersive-environments.md.

When This Skill Activates

• Designing or reviewing a visionOS app, window, volume, or immersive space
• "Users say it's tiring / uncomfortable / hard to hit controls"
• Porting an iPad app and deciding what should become spatial
• Adding hover effects, custom gestures, environments, or spatial audio
• Choosing a video experience format (spatial, 180°, 360°, wide-FOV, Apple Immersive)

The prime directive: find the key moment

Don't window a 2D app. Identify the one thing only possible on visionOS — the "key moment" — and build around it. Immersion has three approaches, and full immersion is not mandatory: full environments · integration with real surroundings (scene sensing) · meaningful audio.

Layout & ergonomics

• Wide beats tall — layouts match the human field of view; turning the head left/right is easier than up/down. Center = primary content; edges = secondary, infrequent actions.
• Default placement sits along the natural line of sight, a bit further than arm's reach; extended reading goes farther out, centered and slightly below eye line.
• Design in points, not meters — dynamic scale keeps windows legible at any distance (they scale up as they move away). Never fixed scale for UI; keep custom UI facing the viewer.
• Depth is hierarchy, used sparingly — "prefer subtle depth" (a modal pushes its parent back). Keep text flat; 3D text is hard to read at an angle.
• Glass, never solid window backgrounds — solid colors block the world, don't adapt to lighting, and "can feel constricting." Elements on glass use vibrancy + white text/symbols; system colors over custom (they're calibrated for legibility). Brand color goes in backgrounds or whole buttons, not glyphs.
• Typography runs heavier than iOS: body = medium (vs regular), titles = bold (vs semibold), slightly increased tracking. Avoid small/lightweight custom fonts.
• Component specs: vertical tab bar fixed left, ≤6 items, expands on gaze · ornaments overlap the window's bottom edge by 20pt, borderless buttons inside · sheets appear centered at the parent's Z while the parent dims and pushes back · nested corners concentric (outer radius = inner + padding).
• SwiftUI spatial layout: stacks default to .back depth alignment — switch to .front when content should read toward the viewer; rotation3DLayout (not rotation3DEffect) when rotation must affect layout; SpatialContainer/spatialOverlay for shared 3D space; scaledToFit3D() for models.

Input: eyes target, hands confirm

• Every interactive element gets ≥60pt of total target area (≈2.5°, ~4.4cm at 1m) — the element can be smaller if surrounding spacing makes up the difference. Standard buttons: 44pt + ≥8pt clearance; stacked buttons ≥16pt apart; list rows 4pt padding so hover effects don't overlap.
• Keep interactive content at one depth — frequent focus-depth changes cause eye strain.
• Eye-target shapes: circles, pills, rounded rectangles; no sharp edges or thick outlines; center text/glyphs with generous padding.
• Every interactive element needs a hover effect — and only interactive elements get one (never read-only data). Hover runs out-of-process: gaze stays private until a gesture.
• Hover rules (WWDC24/25): keep it subtle (a 5% scale is the reference); short delays prevent flicker (reveal effects: ~0.8s in / 0.2s out); effects start from a visible element — no invisible hotspots; high-traffic controls (toolbars, table cells) use ONLY the standard highlight; keep an anchoring element static; respect Reduce Motion (swap for cross-fade).
• Standard gesture language first (pinch = tap, pinch-drag = scroll, two-hand zoom/rotate). Custom gestures must be explainable, repeatable without fatigue, distinct from system gestures, and false-positive-tested; map them to real-world actions.
• Prefer interaction at a distance (eyes target, hands rest in lap) for long sessions; direct touch is for up-close manipulation — compensate for missing tactility (raise buttons, brighten as the finger approaches, snap state + spatial sound on contact).
• Look-to-scroll only in reading/browsing surfaces, never scan-and-pick lists; auto-hiding controls should persist while looked at.