---
id: wiki-2026-0508-시각-전정-충돌-visual-vestibular-confl
title: 시각-전정 충돌(Visual-vestibular conflict)
category: 10_Wiki/Topics
status: verified
canonical_id: self
aliases: [VVC, visual-vestibular mismatch, sensory conflict]
duplicate_of: none
source_trust_level: A
confidence_score: 0.95
verification_status: applied
tags: [vr, perception, sickness, vestibular]
raw_sources: []
last_reinforced: 2026-05-10
github_commit: pending
tech_stack:
  language: any
  framework: vr
---

# 시각-전정 충돌(Visual-vestibular conflict)

## 매 한 줄
> **"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.

## 매 핵심

### 매 메커니즘
- **시각 cue**: optic flow 가 forward motion 을 indicate.
- **전정 cue**: 머리 actual movement 가 zero (sitting still).
- **Mismatch detection**: vestibular nuclei 가 conflict 를 detect.
- **Evolutionary response**: poison hypothesis (Treisman 1977) — nausea, vomit reflex.

### 매 영향 요소
- **FOV**: wider FOV → 매 stronger optic flow → 매 worse VVC.
- **Acceleration**: linear acceleration > constant velocity.
- **Yaw rotation**: smooth turning 이 worst (snap turn 으로 mitigate).
- **Latency**: motion-to-photon > 20ms 시 sickness 가속.

### 매 응용 (mitigation)
1. Teleportation locomotion (no continuous motion).
2. Vignette / tunneling on movement.
3. Snap turn (e.g., 30° increments).
4. High refresh rate (90Hz+, 2026 standard 120Hz).
5. Cockpit / static reference frame.

## 💻 패턴

### Vignette on locomotion (Three.js)
```typescript
import * as THREE from "three";

const vignette = new THREE.ShaderMaterial({
  uniforms: { intensity: { value: 0 } },
  fragmentShader: `
    uniform float intensity;
    varying vec2 vUv;
    void main() {
      float d = distance(vUv, vec2(0.5));
      gl_FragColor = vec4(0., 0., 0., smoothstep(0.3, 0.7, d) * intensity);
    }`
});

function onLocomotion(speed: number) {
  vignette.uniforms.intensity.value = THREE.MathUtils.clamp(speed / 5, 0, 0.7);
}
```

### Snap turn implementation
```typescript
const SNAP_DEGREES = 30;
let lastSnap = 0;
function onThumbstickX(x: number) {
  const now = performance.now();
  if (Math.abs(x) > 0.7 && now - lastSnap > 250) {
    camera.rotation.y -= Math.sign(x) * THREE.MathUtils.degToRad(SNAP_DEGREES);
    lastSnap = now;
  }
}
```

### Teleport locomotion
```typescript
function teleport(target: THREE.Vector3) {
  fadeToBlack(100);
  setTimeout(() => {
    rig.position.copy(target);
    fadeFromBlack(100);
  }, 100);
}
```

### Frame-rate enforcement
```typescript
// 90Hz minimum on Quest 3, 120Hz on Vision Pro
const targetFPS = navigator.userAgent.includes("Vision") ? 120 : 90;
renderer.setAnimationLoop((t, frame) => {
  // skip work if budget exceeded
});
```

## 매 결정 기준
| 상황 | Approach |
|---|---|
| Seated experience | continuous + vignette OK |
| Standing / room scale | teleport + snap turn 권장 |
| Racing / cockpit sim | static cockpit ref → 매 reduces VVC |
| Audience first-time | always teleport default |
| Pro user | option for smooth |

**기본값**: teleport + snap turn 30° + vignette on continuous motion.

## 🔗 Graph
- 부모: [[VR Sickness]]
- 변형: [[Vergence-Accommodation Conflicts]]
- Adjacent: [[가상현실 멀미 (VR Sickness)]] · [[안구 운동 기능 (Oculomotor Functions)]]
- 응용: [[가상현실(VR) 자전거 시뮬레이터]]

## 🤖 LLM 활용
**언제**: locomotion 설계 review · sickness 원인 분석 · UX option 추천.
**언제 X**: actual user testing 의 substitute (subjective experience 측정 필수).

## ❌ 안티패턴
- **Smooth locomotion default**: 매 first-time user 의 30%+ 가 sick.
- **No comfort options**: accessibility 실패.
- **Frame drop tolerance**: 60Hz fallback → severe sickness.
- **Forced rotation**: cinematic 의도 → 즉시 sick.

## 🧪 검증 / 중복
- Verified (Reason & Brand 1975 · Stanney VR Handbook · Meta VR Comfort guidelines).
- 신뢰도 A.

## 🕓 Changelog
| 날짜 | 변경 |
|---|---|
| 2026-05-08 | Phase 1 |
| 2026-05-10 | Manual cleanup — VVC mechanism + mitigation 코드 |
