diff --git a/Intersection/IntrLine3dPlane.cs b/Intersection/IntrLine3dPlane.cs
index 72ec498d6dabc0f6e37fdd28be1a38a6dbbbf188..72262185adbbafb4ba4a993b98ea81fdec7732ce 100644
--- a/Intersection/IntrLine3dPlane.cs
+++ b/Intersection/IntrLine3dPlane.cs
@@ -8,6 +8,8 @@
 */
 
 
+using Unity.Mathematics;
+
 namespace Oroxylum
 {
     /// <summary>
@@ -16,6 +18,6 @@ namespace Oroxylum
     public struct IntrLine3dPlane 
     {
 
-        
+
     }
 }
diff --git a/Math/Line2d.cs b/Math/Line2d.cs
index 5dcd0fbaaf4036031ca449dde53a3b499be4647a..3781f885ed6ba8468e5ae8e680b5f0326509dd9a 100644
--- a/Math/Line2d.cs
+++ b/Math/Line2d.cs
@@ -34,6 +34,12 @@ namespace Oroxylum
 
         public double Project(float2 p) { return (p - Origin).Dot(Direction); }
 
+        public float2 ClosestPoint(float2 p)
+        {
+            float t = (p - Origin).Dot(Direction);
+            return Origin + t * Direction;
+        }
+
         public double DistanceSquared(float2 p)
         {
             float t = (p - Origin).Dot(Direction);
diff --git a/Math/Line3d.cs b/Math/Line3d.cs
new file mode 100644
index 0000000000000000000000000000000000000000..dae02c2f16cea8a3389c66b02789cea8fb5f4189
--- /dev/null
+++ b/Math/Line3d.cs
@@ -0,0 +1,49 @@
+/*
+ *Copyright(C) 2020 by  Cyf All rights reserved.
+ *Unity版本：2021.3.11f1c2 
+ *作者:程一峰  
+ *创建日期: 2022-11-10 
+ *模块说明：木蝴蝶数学库：数据格式
+ *版本: 1.0
+*/
+
+using Unity.Mathematics;
+
+namespace Oroxylum
+{
+    /// <summary>
+    /// 3d 直线
+    /// </summary>
+    public struct Line3d
+    {
+        public float3 Origin;
+        public float3 Direction;
+
+        public Line3d(float3 origin, float3 direction)
+        {
+            this.Origin = origin;
+            this.Direction = direction;
+        }
+
+        public static Line3d FromPoints(float3 p0, float3 p1)
+        {
+            return new Line3d(p0, math.normalize(p1 - p0));
+        }
+
+        public float Project(float3 p) { return (p - Origin).Dot(Direction); }
+
+        public float3 ClosestPoint(float3 p)
+        {
+            float t = (p - Origin).Dot(Direction);
+            return Origin + t * Direction;
+        }
+
+        public float DistanceSquared(float3 p)
+        {
+            float t = (p - Origin).Dot(Direction);
+            float3 proj = Origin + t * Direction;
+            return (proj - p).LengthSquared();
+        }
+
+    }
+}
\ No newline at end of file
diff --git a/Math/Plane.cs.meta b/Math/Line3d.cs.meta
similarity index 83%
rename from Math/Plane.cs.meta
rename to Math/Line3d.cs.meta
index 16d29febc9f941dc917d6bc1a5dd859d4e679314..cb8962d08d6efecbfb14af7f30c1095c8a0c43d9 100644
--- a/Math/Plane.cs.meta
+++ b/Math/Line3d.cs.meta
@@ -1,5 +1,5 @@
 fileFormatVersion: 2
-guid: 4ea5947ca82e2104da89c84439ced2f7
+guid: 43c47208483b92d40b735849b69bfff2
 MonoImporter:
   externalObjects: {}
   serializedVersion: 2
diff --git a/Math/Plane.cs b/Math/Plane.cs
deleted file mode 100644
index b33f4187a20c17f8a175353c448d6aee372853c8..0000000000000000000000000000000000000000
--- a/Math/Plane.cs
+++ /dev/null
@@ -1,21 +0,0 @@
-/*
- *Copyright(C) 2020 by  Cyf All rights reserved.
- *Unity版本：2021.3.11f1c2 
- *作者:程一峰  
- *创建日期: 2022-11-10 
- *模块说明：木蝴蝶数学库：数据格式
- *版本: 1.0
-*/
-
-
-namespace Oroxylum
-{
-    /// <summary>
-    /// 平面
-    /// </summary>
-    public struct Plane
-    {
-
-
-    }
-}
\ No newline at end of file
diff --git a/OMath.cs b/OMath.cs
index 6ceda00e2962a3bcff35e996741106d825343536..3c9ba300491aec070550d51f55cdeceeec342f57 100644
--- a/OMath.cs
+++ b/OMath.cs
@@ -154,6 +154,8 @@ namespace Oroxylum
 
         public static float LengthSquared(this float2 a) { return math.lengthsq(a); }
 
+        public static float LengthSquared(this float3 a) { return math.lengthsq(a); }
+
         public static float DotPerp(this float2 a, float2 b) { return (a.x * b.y) - (a.y * b.x); }
 
         /// <summary>