Assets (S6)

• All models passed gltf-transform validate
• Geometries compressed (Draco or Meshopt)
• Textures compressed (KTX2 with UASTC for normals, ETC1S for rest)
• Textures no larger than needed (2K mobile max, 4K desktop max)
• LOD levels authored for any mesh appearing at varying distances
• Texture atlases built where ≥10 similar assets
• Assets served with immutable, max-age=31536000 cache headers
• CDN with Brotli compression on .json/.gltf

Rendering quality

• Color management set: outputColorSpace = SRGBColorSpace, textures flagged correctly
• Tone mapping picked (ACESFilmicToneMapping) and exposure tuned
• PMREM environment set for PBR materials to have specular IBL
• Shadow map size appropriate (1024 or 2048, not 4096 default)
• Pixel ratio clamped: renderer.setPixelRatio(Math.min(devicePixelRatio, 2))
• Post-processing gated by device tier (skip bloom/DOF/SSAO on low)

Performance

• Named imports from 'three' — no * as THREE
• GLTFLoader / DRACOLoader / KTX2Loader lazy-imported
• Bundle analyzer run, nothing > 200KB surprise
• Total JS bundle < 300KB (first paint)
• FPS p10 ≥ 30 on low-tier device (tested)
• Frustum culling enabled on Meshes (default, verify)
• Instancing (InstancedMesh/BatchedMesh) for repeated geometry
• Animation mixer paused when tab inactive

UI & UX (S7)

• Loading state shown — never blank canvas on load
• Error states messaged — never silent failure
• Touch gestures work on mobile (touch-action: none)
• Keyboard alternative for every gesture (arrow keys, Tab)
• aria-label on canvas container
• Screen reader announcements via aria-live
• prefers-reduced-motion respected
• Text uses MSDF or sharp HTML overlay (not blurry canvas)

Reliability

• webglcontextlost handler with preventDefault()
• webglcontextrestored handler that reinit's
• GLTFLoader error callback handles failures with fallback
• Network requests have timeouts (10s or less)
• Capability tiers detected, rendering adjusted
• No-WebGL fallback (static image + message)

Observability

• web-vitals LCP/CLS/INP reporting
• Custom "3D ready" metric
• FPS p10/p50/p90 reporting (not just avg)
• Long Task Observer hooked
• Error tracking (window.error + unhandledrejection)
• Device tier segmentation on all metrics
• Alerting on p10 FPS regression

Security & privacy

• CSP headers set (allow unpkg/CDN you actually use, nothing more)
• Self-hosted Draco + Basis decoders (not gstatic in prod)
• No PII in telemetry events
• GDPR: telemetry requires consent (or anonymous)
• User-generated 3D content validated (size, format, malicious glTF)

Launch day

• Feature flag ready (Launch Darkly, GrowthBook, manual) to disable 3D if something breaks
• Rollback plan: previous deploy tagged and ready
• On-call engineer identified
• Dashboards bookmarked and tested
• 10% gradual rollout, not 100% big bang
• Cross-device smoke test: Quest, iPhone, Chromebook, modern Mac
• Lighthouse score >= 90

Season 8 recap

State → ECS → loops → authoring → debug → testing → errors → build → telemetry → checklist.

The engineering scaffolding that turns a demo into a product. Every item here either catches or prevents a production outage.

Season 9 next

Real-time Systems & Audio. WebRTC for voice/video streams. Web Audio API deep dive. Spatial audio. Convolution reverb. Audio-reactive visuals. Multiplayer sync. The sound half of "3D experience."