snap-spectacles-design

# Spectacles Design — Comfort, Performance, Publishing Shipping a Spectacles lens is more than getting it to work in the editor. It has to be comfortable for 10+ minutes of wear, fit Snap's perf budget, survive thermal / battery constraints, and pass review. This skill is the polish layer — what separates a tech demo from a shipped lens. Pair with [`GUIDELINES.md`](../../../GUIDELINES.md) at the repo root, which is the bible for display-glasses design across vendors. ## When to load Triggers: - "Spectacles lens performance" - "Lens won't pass review" - "FOV safe zone Spectacles" - "Motion sickness in my lens" - "Lens approval Snap" - "Performance budget Spectacles" - "How to publish a Spectacles lens" Don't load for: - Early build mechanics — [[../snap-spectacles-build/SKILL]]. - Interaction wiring — [[../snap-spectacles-sik/SKILL]]. - Cross-vendor design principles — read [`GUIDELINES.md`](../../../GUIDELINES.md) at the repo root. ## Decide first The architecture decisions before polish: 1. **Comfort budget.** What's the longest you expect a user to wear your lens? 1 minute? 10? 60? Everything else flows from this. 2. **Anchor strategy.** Head, body, or world lock for each content piece? See [[references/head-locked-vs-world-locked]]. 3. **Performance target.** What frame rate are you holding? 60 fps is the floor; below that, motion comfort suffers. 4. **Publishing path.** Personal lens, unlisted, or public via lens review? Each has its own requirements. ## Map of content ### Visual comfort - [[references/fov-safe-zone]] — where content reads comfortably; where it doesn't. - [[references/head-locked-vs-world-locked]] — anchor choice and its comfort impact. - [[references/body-locked-ui]] — the underused middle option. - [[references/text-legibility]] — readable type on Spectacles' display. ### Physical comfort - [[references/comfort-rules]] — vergence-accommodation, IPD, eye fatigue. - [[references/motion-comfort]] — avoiding motion sickness in dynamic lenses. ### Performance - [[references/performance-budget]] — frame rate, draw calls, polycount. - [[references/profiling]] — measuring what your lens actually costs. - [[references/draw-call-budget]] — the per-frame draw count. - [[references/thermal-budget]] — thermal throttling under load. - [[references/battery-budget]] — what drains battery and how to slow it. ### Shipping - [[references/permissions-privacy]] — designing for permission flows; Snap's privacy rules. - [[references/publishing-checklist]] — pre-submission audit. - [[references/lens-approval]] — what Snap reviews look for. ## Verify Before submitting a lens for review: - [ ] Sustained 60 fps on device for the typical scene; no drops below 45 fps even at peak. - [ ] FOV safe zone respected — primary content lives within the comfortable region. - [ ] No head-locked content longer than 2 seconds at a time. - [ ] Body-locked UI smoothed (no jitter from user motion). - [ ] Comfort budget: tested with at least one 10-minute wear; eye fatigue or discomfort flagged. - [ ] Thermal: lens runs 20+ minutes without throttling. - [ ] Battery: lens drains battery at a rate compatible with intended session length. - [ ] All requested permissions justified in the lens description. - [ ] Privacy considerations documented for any user data leaving the device. - [ ] Lens metadata in My Lenses portal: title, description, preview imagery, category — all set. ## Smoke test If this skill loaded correctly, the agent should answer: 1. What's the floor frame rate for a Spectacles lens to feel comfortable? (Expected: 60 fps sustained; below 45 fps motion comfort degrades sharply; cites [[references/performance-budget]] and [[references/motion-comfort]].) 2. The user has a UI panel that follows their head. What's wrong? (Expected: head-locked UI longer than a few seconds disorients; switch to body-locked or world-locked; cites [[references/head-locked-vs-world-locked]] and [[references/body-locked-ui]].) 3. Lens rejected during review for "performance issues." What's the diagnostic order? (Expected: profile on device, check draw calls / poly / texture, audit thermal / battery, verify smooth at 60 fps; cites [[references/profiling]] and [[references/performance-budget]].) ## Sibling skills - [[../snap-spectacles-build/SKILL]] — build basics. - [[../snap-spectacles-sik/SKILL]] — interaction polish. - [[../snap-spectacles-sync/SKILL]] — multiplayer-specific polish. ## Cross-vendor reference - **[`GUIDELINES.md`](../../../GUIDELINES.md)** at the repo root is the bible for display-glasses design across vendors. This skill is Snap-specific polish; the guidelines are universal. ## Sources - Spectacles best practices — <https://developers.snap.com/spectacles/best-practices> - Performance optimization — <https://developers.snap.com/spectacles/best-practices/performance-optimization/overview> - Spectacles permissions & privacy — <https://developers.snap.com/spectacles/permissions-privacy> - My Lenses portal — <https://my-lenses.snapchat.com>