2nd/10_Wiki/Topics/Architecture/VR_Sickness.md

---
id: wiki-2026-0508-vr-sickness
title: VR Sickness
category: 10_Wiki/Topics
status: verified
canonical_id: self
aliases: [Cybersickness, VR Motion Sickness, Simulator Sickness]
duplicate_of: none
source_trust_level: A
confidence_score: 0.9
verification_status: applied
tags: [vr, ux, perception, comfort]
raw_sources: []
last_reinforced: 2026-05-10
github_commit: pending
tech_stack:
  language: csharp
  framework: unity-xr
---

# VR Sickness

## 매 한 줄
> **"매 vestibular system 매 시각-전정 mismatch 매 만들면 매 nausea 의 발생"**. 매 1990s simulator sickness 연구의 매 VR 확장 — 매 2026 매 Quest 3, Vision Pro, Pico 4 Ultra 매 90Hz+ / foveated rendering 으로 매 줄어들고 있지만 매 design choice (locomotion, FOV) 가 매 dominant factor.

## 매 핵심

### 매 원인 (Sensory Conflict Theory)
- **Visual-vestibular mismatch**: 눈은 movement 보지만 inner ear 는 stationary 신호 — 매 brain 의 "독 상태" 추정.
- **Latency**: motion-to-photon > 20ms 매 sickness 급증.
- **Low frame rate**: < 90Hz, 특히 dropped frame, 매 trigger.
- **FOV manipulation**: peripheral vision movement 매 강한 vection.
- **IPD mismatch**: 매 잘못된 inter-pupillary distance 매 eye strain → nausea.
- **Acceleration in virtual locomotion**: 매 constant velocity OK, 매 acceleration 의 매 worst.

### 매 완화 기법
- **Teleport locomotion**: 매 smooth move 보다 매 sickness ~80% 감소.
- **Tunneling / vignette**: peripheral 의 dark mask, vection 줄임.
- **Snap turn**: smooth turn 대신 30~45° 매 step rotation.
- **Static reference frame**: cockpit, helmet rim 등 매 fixed visual anchor.
- **High refresh + reprojection**: 90Hz 이상 + ATW/ASW.
- **Foveated rendering**: 매 GPU budget 매 free up → frame stability.

### 매 응용
1. Beat Saber: stationary play, 매 sickness rare.
2. Half-Life Alyx: teleport + smooth 양쪽 옵션, comfort slider.
3. Microsoft Flight Sim VR: cockpit anchor, 매 long-session OK.
4. No Man's Sky VR: smooth locomotion default — 매 highest sickness reports.

## 💻 패턴

### Comfort vignette (Unity URP)
```csharp
// 매 movement speed 매 따라 매 peripheral mask 매 강도 조절
using UnityEngine;
using UnityEngine.Rendering.Universal;

public class ComfortVignette : MonoBehaviour {
    [SerializeField] Vignette vignette;
    [SerializeField] CharacterController player;
    [SerializeField] float maxIntensity = 0.6f;

    void Update() {
        float speed = player.velocity.magnitude;
        float t = Mathf.Clamp01(speed / 4f); // 4 m/s 매 full vignette
        vignette.intensity.value = t * maxIntensity;
    }
}
```

### Snap turn input
```csharp
public class SnapTurn : MonoBehaviour {
    [SerializeField] Transform xrRig;
    [SerializeField] float snapDegrees = 30f;
    [SerializeField] float deadzone = 0.7f;
    bool armed = true;

    void Update() {
        float x = OVRInput.Get(OVRInput.Axis2D.SecondaryThumbstick).x;
        if (Mathf.Abs(x) < deadzone) { armed = true; return; }
        if (!armed) return;
        xrRig.Rotate(0, Mathf.Sign(x) * snapDegrees, 0);
        armed = false;
    }
}
```

### Teleport locomotion (XR Interaction Toolkit)
```csharp
// 매 XRI 의 매 TeleportationProvider + arc raycaster 사용
using UnityEngine;
using UnityEngine.XR.Interaction.Toolkit.Locomotion.Teleportation;

public class TeleportTrigger : MonoBehaviour {
    [SerializeField] TeleportationProvider provider;
    public void RequestTeleport(Vector3 destination) {
        var req = new TeleportRequest {
            destinationPosition = destination,
            matchOrientation = MatchOrientation.WorldSpaceUp,
        };
        provider.QueueTeleportRequest(req);
    }
}
```

### Frame timing budget check
```csharp
// 매 frame budget 위반 매 detect — Quest 3 매 11.1ms@90Hz, 8.3ms@120Hz
void LateUpdate() {
    float budget = 1f / Application.targetFrameRate;
    if (Time.unscaledDeltaTime > budget * 1.2f) {
        Debug.LogWarning($"Frame overran: {Time.unscaledDeltaTime*1000f:F1}ms");
    }
}
```

### IPD calibration
```csharp
// OpenXR 매 user IPD 매 read — 매 잘못 설정 매 nausea 의 hidden cause
using UnityEngine.XR;

float GetIpdMeters() {
    var head = InputDevices.GetDeviceAtXRNode(XRNode.Head);
    head.TryGetFeatureValue(CommonUsages.eyesData, out var eyes);
    var l = eyes.leftEye.position;
    var r = eyes.rightEye.position;
    return Vector3.Distance(l, r);
}
```

### Dynamic foveated rendering toggle (Quest 3)
```csharp
// Quest 3 매 eye-tracked foveation — frame stability 의 강력한 도구
OVRManager.eyeTrackedFoveatedRenderingEnabled = true;
OVRManager.foveatedRenderingLevel = OVRManager.FoveatedRenderingLevel.HighTop;
```

## 매 결정 기준
| 상황 | Approach |
|---|---|
| Casual / first-time user | Teleport + snap turn default |
| Action / FPS | Smooth + vignette + snap turn option |
| Sim (flight, racing) | Cockpit anchor, smooth, 90Hz+ guaranteed |
| Standing-only experience | 거의 sickness-free — Beat Saber model |
| Seated narrative | Static camera + cuts, no virtual locomotion |

**기본값**: Comfort menu 의 매 모든 option 매 expose — user 가 choose.

## 🔗 Graph
- 변형: [[Cybersickness]] · [[Simulator Sickness]]

## 🤖 LLM 활용
**언제**: VR comfort design review, locomotion option 추천, frame budget 분석.
**언제 X**: AR / pass-through 만 (vestibular conflict 적음), non-immersive VR / 360 video.

## ❌ 안티패턴
- **Forced smooth locomotion**: comfort option 의 X — 매 user churn.
- **Cinematic camera shake**: VR 매 절대 X — 매 immediate nausea.
- **Acceleration / deceleration smooth curve**: linear 보다 매 더 sick.
- **Stuttering / dropped frames**: 60Hz 의 매 X — 매 90Hz minimum.
- **High-altitude vertigo without snap**: 매 some users 매 panic + sickness.
- **No comfort settings menu**: 2026 매 standard expectation.

## 🧪 검증 / 중복
- Verified (Oculus Best Practices 2025, Apple Vision Pro HIG, IEEE VR 2025 cybersickness papers).
- 신뢰도 A.

## 🕓 Changelog
| 날짜 | 변경 |
|---|---|
| 2026-05-08 | Phase 1 |
| 2026-05-10 | Manual cleanup — sensory conflict theory, mitigation patterns, Unity XR code |