diff --git a/Assets/External/OptiTrack Unity Plugin/OptiTrack/Scripts/OptitrackStreamingClient.cs b/Assets/External/OptiTrack Unity Plugin/OptiTrack/Scripts/OptitrackStreamingClient.cs
index 0283712c7..ce86a1d0b 100644
--- a/Assets/External/OptiTrack Unity Plugin/OptiTrack/Scripts/OptitrackStreamingClient.cs	
+++ b/Assets/External/OptiTrack Unity Plugin/OptiTrack/Scripts/OptitrackStreamingClient.cs	
@@ -331,6 +331,10 @@ public class OptitrackStreamingClient : MonoBehaviour
     //[Tooltip("Timecode Provider")]
     //public bool TimecodeProvider = false;
 
+    [Header("Mirror Mode")]
+    [Tooltip("모든 스켈레톤 본과 리지드바디의 좌우를 거울 반전합니다.")]
+    public bool MirrorMode = false;
+
 
     #region Private fields
     //private UInt16 ServerCommandPort = NatNetConstants.DefaultCommandPort;
@@ -361,6 +365,9 @@ public class OptitrackStreamingClient : MonoBehaviour
     /// <summary>Maps from a streamed skeleton's ID to its most recent available pose data.</summary>
     private Dictionary<Int32, OptitrackSkeletonState> m_latestSkeletonStates = new Dictionary<Int32, OptitrackSkeletonState>();
 
+    /// <summary>MirrorMode용: 스켈레톤 ID → (boneId → mirrorBoneId) 매핑 캐시.</summary>
+    private Dictionary<Int32, Dictionary<Int32, Int32>> m_mirrorBoneIdMaps = new Dictionary<Int32, Dictionary<Int32, Int32>>();
+
     /// <summary>Maps from a streamed trained markerset's ID to its most recent available pose data.</summary>
     private Dictionary<Int32, OptitrackTMarkersetState> m_latestTMarkersetStates = new Dictionary<Int32, OptitrackTMarkersetState>(); // trained markerset added
 
@@ -868,8 +875,20 @@ public class OptitrackStreamingClient : MonoBehaviour
 
             rbState = new OptitrackRigidBodyState();
             RigidBodyDataToState( rbData, OptitrackHiResTimer.Now(), rbState );
+        }
 
-            
+        if ( MirrorMode && rbState != null )
+        {
+            rbState = new OptitrackRigidBodyState
+            {
+                DeliveryTimestamp = rbState.DeliveryTimestamp,
+                IsTracked = rbState.IsTracked,
+                Pose = new OptitrackPose
+                {
+                    Position    = MirrorPosition( rbState.Pose.Position ),
+                    Orientation = MirrorOrientation( rbState.Pose.Orientation ),
+                }
+            };
         }
 
         return rbState;
@@ -914,15 +933,80 @@ public class OptitrackStreamingClient : MonoBehaviour
             deliveryTimestamp = state.DeliveryTimestamp;
             posOut.Clear();
             oriOut.Clear();
-            foreach ( var kvp in state.BonePoses )
+
+            if ( MirrorMode )
             {
-                posOut[kvp.Key] = kvp.Value.Position;
-                oriOut[kvp.Key] = kvp.Value.Orientation;
+                Dictionary<Int32, Int32> mirrorMap = GetOrBuildMirrorBoneIdMap( skeletonId );
+                foreach ( var kvp in state.BonePoses )
+                {
+                    Int32 targetId = mirrorMap != null && mirrorMap.TryGetValue( kvp.Key, out Int32 mid ) ? mid : kvp.Key;
+                    posOut[targetId] = MirrorPosition( kvp.Value.Position );
+                    oriOut[targetId] = MirrorOrientation( kvp.Value.Orientation );
+                }
+            }
+            else
+            {
+                foreach ( var kvp in state.BonePoses )
+                {
+                    posOut[kvp.Key] = kvp.Value.Position;
+                    oriOut[kvp.Key] = kvp.Value.Orientation;
+                }
             }
             return true;
         }
     }
 
+    /// <summary>
+    /// 본 이름의 L/R 접두사를 반전한 이름을 반환. 대칭 본이면 null.
+    /// 예: "LUArm" → "RUArm", "RShin" → "LShin", "Hip" → null
+    /// </summary>
+    private static string GetMirrorBoneName( string name )
+    {
+        if ( string.IsNullOrEmpty( name ) || name.Length < 2 ) return null;
+        if ( name[0] == 'L' && char.IsUpper( name[1] ) ) return "R" + name.Substring( 1 );
+        if ( name[0] == 'R' && char.IsUpper( name[1] ) ) return "L" + name.Substring( 1 );
+        return null;
+    }
+
+    /// <summary>
+    /// 스켈레톤 정의를 기반으로 boneId → mirrorBoneId 매핑을 빌드하고 캐시에 저장.
+    /// m_frameDataUpdateLock 내에서 호출해야 함.
+    /// </summary>
+    private Dictionary<Int32, Int32> GetOrBuildMirrorBoneIdMap( Int32 skeletonId )
+    {
+        if ( m_mirrorBoneIdMaps.TryGetValue( skeletonId, out var cached ) )
+            return cached;
+
+        OptitrackSkeletonDefinition skelDef = GetSkeletonDefinitionById( skeletonId );
+        if ( skelDef == null ) return null;
+
+        // 이름 → ID 룩업 테이블
+        var nameToId = new Dictionary<string, Int32>( skelDef.Bones.Count );
+        foreach ( var bone in skelDef.Bones )
+            nameToId[bone.Name] = bone.Id;
+
+        var map = new Dictionary<Int32, Int32>( skelDef.Bones.Count );
+        foreach ( var bone in skelDef.Bones )
+        {
+            string mirrorName = GetMirrorBoneName( bone.Name );
+            if ( mirrorName != null && nameToId.TryGetValue( mirrorName, out Int32 mirrorId ) )
+                map[bone.Id] = mirrorId;
+            else
+                map[bone.Id] = bone.Id; // 대칭 본은 자기 자신에 매핑
+        }
+
+        m_mirrorBoneIdMaps[skeletonId] = map;
+        return map;
+    }
+
+    /// <summary>YZ 평면 기준 회전 미러: X, Z 성분 부호 반전.</summary>
+    private static Quaternion MirrorOrientation( Quaternion q )
+        => new Quaternion( -q.x, q.y, -q.z, q.w );
+
+    /// <summary>YZ 평면 기준 위치 미러: X 성분 부호 반전.</summary>
+    private static Vector3 MirrorPosition( Vector3 pos )
+        => new Vector3( -pos.x, pos.y, pos.z );
+
 
     /// <summary>Get the most recently received state for the specified trained markerset.</summary>
     /// <param name="tmarkersetId">
@@ -1113,6 +1197,7 @@ public class OptitrackStreamingClient : MonoBehaviour
         m_rigidBodyDefinitions.Clear();
         m_skeletonDefinitions.Clear();
         m_tmarkersetDefinitions.Clear();
+        m_mirrorBoneIdMaps.Clear(); // 스켈레톤 정의 변경 시 mirror map 캐시 무효화
 
         // ----------------------------------
         // - Translate Rigid Body Definitions