Question Lidar Ray Tracing Problem

Hi forum,

I am doing a Lidar Simulation on Unity currently and I'm facing a problem, which made me feel really confused.
In Lidar simulation, the Lidar rotates and dispatches rays, my goal is to generate a point cloud after scanning, here I use red balls to represent points.

The Problem is why the rays I visualized do not stop at hit points but go through objects?
Do I need to add a shader to every scanned object to achieve the goal?

I used Debug.DrawRay to show ray directions (blue) in scene, and I also checked the colliders of surrounding objects, but it did not help. In C# script I added all objects in scene to RayTracingAccelerationStructure and set pool for balls, which represents the hit points in order to visualize the point cloud.

Here are the screenshots of my project, it shows that rays go through objects:



Also I upload the c# scripts and shader here in attachment.

The .raytrace file can't be uploaded so I post it here in text (hlsl code, not csharp):

Code (CSharp):

1. // LiDARRayTracingShader.raytrace
2.  
3. #pragma raytracing
4.  
5.  
6.  
7. // Accelerated structure declaration
8. RaytracingAccelerationStructure _AccelerationStructure : register(t0);
9.  
10. // Input and output structure
11. struct RayGenInput
12. {
13.     float3 RayOrigin : ORIGIN;
14.     float3 RayDirection : DIRECTION;
15. };
16.  
17. struct RayGenOutput
18. {
19.     float3 HitPoint : SV_Position;
20. };
21.  
22. struct Attributes
23. {
24.     float2 barycentrics;
25. };
26.  
27. struct RayPayload
28. {
29.     float HitDistance;
30.     float3 HitColor;
31.     float3 color;
32.     float t;
33. };
34.  
35. // global variable
36. float _MaxDistance;
37. int _NumberOfRays;
38. float3 _RayOrigin;
39. float3 _BackgroundColor = float3(0.5, 0.5, 0.5);
40. RWStructuredBuffer<float3> _HitPoints;
41.  
42.  
43. // Ray generation shader
44. [shader("raygeneration")]
45. void RaygenLiDAR()
46. {
47.     uint2 launchIndex = DispatchRaysIndex().xy;
48.  
49.     // Calculate ray direction
50.     float angle = 2.0f * 3.14159265359f * (launchIndex.x / (float)_NumberOfRays);
51.     float3 direction = float3(cos(angle), 0, sin(angle));
52.  
53.     // Initialising the light payload
54.     RayPayload payload;
55.     payload.HitDistance = -1; // An initial value of -1 indicates a miss
56.     payload.HitColor = _BackgroundColor; // Initial colour is the background colour
57.  
58.     // send out rays
59.     RayDesc ray = { _RayOrigin, 0, direction, _MaxDistance }; // Use the default ray starting point
60.     TraceRay(_AccelerationStructure, RAY_FLAG_CULL_BACK_FACING_TRIANGLES, 0xFF, 0, 1, 0, ray, payload);
61.  
62.     // Processing results based on payload
63.     if (payload.HitDistance > 0)
64.     {
65.         float3 hitPoint = float3(0,0,0) + direction * payload.HitDistance;
66.         _HitPoints[launchIndex.x] = hitPoint;
67.     }
68.     else
69.     {
70.         _HitPoints[launchIndex.x] = float3(0, -1000, 0); // Use an invalid value to indicate no hit
71.     }
72. }
73.  
74. // Miss shader
75. [shader("miss")]
76. void MissShader(inout RayPayload payload)
77. {
78.     // when the ray does not hit any object（
79.     payload.HitDistance = -1;
80.     payload.HitColor = _BackgroundColor;
81.    
82. }
83.  
84.  
85. // Closest hit shader
86. [shader("closesthit")]
87. void ClosestHit(inout RayPayload payload, Attributes attrib)
88. {
89.     payload.color = float3(1, 0, 0); // red
90.     payload.HitDistance = payload.t; // Store the intersection distance
91.    
92. }

Thank you for reading this and any advice would be useful for me!