Spatial interface contract

Choose the least immersive presentation that serves the task. Shared-space interoperability and physical comfort are defaults; immersion is an explicit, reversible choice.

Presentation choice

• Window: familiar information and controls; resize and distance tolerant.
• Volume: bounded 3D content that benefits from inspection from multiple sides.
• Full space: environment-scale or high-immersion work whose value justifies isolation, orientation risk, and a deliberate transition.

Required doctrine

• Keep primary controls within a comfortable visual and reach field. Avoid repeated head/neck movement, extreme depth changes, and peripheral targets.
• Maintain stable reference frames. Do not move the world or horizon to create spectacle; provide non-motion alternatives for locomotion and transitions.
• Give gaze targets sufficient spacing and visible focus feedback without exposing or inferring private gaze history.
• Use depth to express hierarchy or spatial meaning, not decoration. Prevent occlusion, z-fighting, accidental input, and unreadable content over variable surroundings.
• Put persistent contextual actions in predictable ornaments or controls, without surrounding the person with chrome.
• Preserve passthrough awareness and safe boundaries unless the person knowingly enters immersion. Make entry, exit, and recovery obvious.
• Provide a 2D or non-spatial fallback for every core task.

Test matrix

Review seated and standing, different heights and reach, cluttered and bright surroundings, low vision, reduced motion, one-handed interaction, interruption, shared-space competition, recentering, tracking loss, and full-space exit.

Source: Apple HIG Spatial layout, observed 2026-07-13.