138 lines
4.3 KiB
Markdown
138 lines
4.3 KiB
Markdown
---
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id: wiki-2026-0508-시각-전정-충돌-visual-vestibular-confl
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title: 시각-전정 충돌(Visual-vestibular conflict)
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category: 10_Wiki/Topics
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status: verified
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canonical_id: self
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aliases: [VVC, visual-vestibular mismatch, sensory conflict]
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duplicate_of: none
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source_trust_level: A
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confidence_score: 0.95
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verification_status: applied
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tags: [vr, perception, sickness, vestibular]
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raw_sources: []
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last_reinforced: 2026-05-10
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github_commit: pending
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tech_stack:
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language: any
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framework: vr
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---
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# 시각-전정 충돌(Visual-vestibular conflict)
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## 매 한 줄
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> **"매 visual motion 과 vestibular system 의 input mismatch 가 sickness 를 유발한다"**. Reason & Brand 의 1975 sensory conflict theory — VR 에서 user 가 see motion but feel stationary (or vice versa) 시, 매 brain 이 conflict 를 poison signal 로 misinterpret. 매 modern VR 의 #1 design constraint.
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## 매 핵심
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### 매 메커니즘
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- **시각 cue**: optic flow 가 forward motion 을 indicate.
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- **전정 cue**: 머리 actual movement 가 zero (sitting still).
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- **Mismatch detection**: vestibular nuclei 가 conflict 를 detect.
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- **Evolutionary response**: poison hypothesis (Treisman 1977) — nausea, vomit reflex.
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### 매 영향 요소
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- **FOV**: wider FOV → 매 stronger optic flow → 매 worse VVC.
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- **Acceleration**: linear acceleration > constant velocity.
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- **Yaw rotation**: smooth turning 이 worst (snap turn 으로 mitigate).
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- **Latency**: motion-to-photon > 20ms 시 sickness 가속.
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### 매 응용 (mitigation)
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1. Teleportation locomotion (no continuous motion).
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2. Vignette / tunneling on movement.
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3. Snap turn (e.g., 30° increments).
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4. High refresh rate (90Hz+, 2026 standard 120Hz).
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5. Cockpit / static reference frame.
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## 💻 패턴
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### Vignette on locomotion (Three.js)
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```typescript
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import * as THREE from "three";
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const vignette = new THREE.ShaderMaterial({
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uniforms: { intensity: { value: 0 } },
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fragmentShader: `
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uniform float intensity;
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varying vec2 vUv;
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void main() {
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float d = distance(vUv, vec2(0.5));
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gl_FragColor = vec4(0., 0., 0., smoothstep(0.3, 0.7, d) * intensity);
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}`
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});
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function onLocomotion(speed: number) {
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vignette.uniforms.intensity.value = THREE.MathUtils.clamp(speed / 5, 0, 0.7);
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}
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```
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### Snap turn implementation
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```typescript
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const SNAP_DEGREES = 30;
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let lastSnap = 0;
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function onThumbstickX(x: number) {
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const now = performance.now();
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if (Math.abs(x) > 0.7 && now - lastSnap > 250) {
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camera.rotation.y -= Math.sign(x) * THREE.MathUtils.degToRad(SNAP_DEGREES);
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lastSnap = now;
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}
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}
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```
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### Teleport locomotion
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```typescript
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function teleport(target: THREE.Vector3) {
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fadeToBlack(100);
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setTimeout(() => {
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rig.position.copy(target);
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fadeFromBlack(100);
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}, 100);
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}
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```
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### Frame-rate enforcement
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```typescript
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// 90Hz minimum on Quest 3, 120Hz on Vision Pro
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const targetFPS = navigator.userAgent.includes("Vision") ? 120 : 90;
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renderer.setAnimationLoop((t, frame) => {
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// skip work if budget exceeded
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});
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```
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## 매 결정 기준
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| 상황 | Approach |
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|---|---|
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| Seated experience | continuous + vignette OK |
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| Standing / room scale | teleport + snap turn 권장 |
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| Racing / cockpit sim | static cockpit ref → 매 reduces VVC |
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| Audience first-time | always teleport default |
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| Pro user | option for smooth |
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**기본값**: teleport + snap turn 30° + vignette on continuous motion.
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## 🔗 Graph
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- 부모: [[VR Sickness]]
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- 변형: [[Vergence-Accommodation Conflicts]]
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- Adjacent: [[가상현실 멀미 (VR Sickness)]] · [[안구 운동 기능 (Oculomotor Functions)]]
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- 응용: [[가상현실(VR) 자전거 시뮬레이터]]
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## 🤖 LLM 활용
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**언제**: locomotion 설계 review · sickness 원인 분석 · UX option 추천.
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**언제 X**: actual user testing 의 substitute (subjective experience 측정 필수).
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## ❌ 안티패턴
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- **Smooth locomotion default**: 매 first-time user 의 30%+ 가 sick.
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- **No comfort options**: accessibility 실패.
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- **Frame drop tolerance**: 60Hz fallback → severe sickness.
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- **Forced rotation**: cinematic 의도 → 즉시 sick.
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## 🧪 검증 / 중복
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- Verified (Reason & Brand 1975 · Stanney VR Handbook · Meta VR Comfort guidelines).
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- 신뢰도 A.
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## 🕓 Changelog
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| 날짜 | 변경 |
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|---|---|
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| 2026-05-08 | Phase 1 |
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| 2026-05-10 | Manual cleanup — VVC mechanism + mitigation 코드 |
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