diff --git a/src/DotRecast.Core/Numerics/RcVec3f.cs b/src/DotRecast.Core/Numerics/RcVec3f.cs
index 4543f14..683b69d 100644
--- a/src/DotRecast.Core/Numerics/RcVec3f.cs
+++ b/src/DotRecast.Core/Numerics/RcVec3f.cs
@@ -122,28 +122,6 @@ namespace DotRecast.Core.Numerics
         }
 
 
-
-
-        /// Derives the dot product of two vectors on the xz-plane. (@p u . @p v)
-        /// @param[in] u A vector [(x, y, z)]
-        /// @param[in] v A vector [(x, y, z)]
-        /// @return The dot product on the xz-plane.
-        ///
-        /// The vectors are projected onto the xz-plane, so the y-values are
-        /// ignored.
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public readonly float Dot2D(RcVec3f v)
-        {
-            return X * v.X + Z * v.Z;
-        }
-
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public readonly float Dot2D(float[] v, int vi)
-        {
-            return X * v[vi] + Z * v[vi + 2];
-        }
-
-
         public override bool Equals(object obj)
         {
             if (!(obj is RcVec3f))
diff --git a/src/DotRecast.Core/Numerics/RcVecExtensions.cs b/src/DotRecast.Core/Numerics/RcVecExtensions.cs
index d2e5dd7..b17786c 100644
--- a/src/DotRecast.Core/Numerics/RcVecExtensions.cs
+++ b/src/DotRecast.Core/Numerics/RcVecExtensions.cs
@@ -28,11 +28,32 @@ namespace DotRecast.Core.Numerics
                 default: throw new IndexOutOfRangeException("vector3f index out of range");
             }
         }
-        
+
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static RcVec3f Scale(this RcVec3f v, float scale)
         {
             return v * scale;
         }
+
+        /// Derives the dot product of two vectors on the xz-plane. (@p u . @p v)
+        /// @param[in] u A vector [(x, y, z)]
+        /// @param[in] v A vector [(x, y, z)]
+        /// @return The dot product on the xz-plane.
+        ///
+        /// The vectors are projected onto the xz-plane, so the y-values are
+        /// ignored.
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static float Dot2D(this RcVec3f @this, RcVec3f v)
+        {
+            return @this.X * v.X +
+                   @this.Z * v.Z;
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static float Dot2D(this RcVec3f @this, float[] v, int vi)
+        {
+            return @this.X * v[vi] +
+                   @this.Z * v[vi + 2];
+        }
     }
 }
\ No newline at end of file