Detect all collision points with Raycast

Questions & Answers
1

I want to cast a ray and collect all the points where it collided with objects.
But for some reason when I cast the ray, I get only 1 hit point per gameobject. The point where ray exits the gameobject is ignored. Why?

 RaycastHit[] hits;
    hits = Physics.RaycastAll(ray, MaxLength);
    for(int i = 0; i < hits.Length; i++)
    {
        RaycastHit hit = hits*;*

GameObject goHitall = hit.transform.gameObject;
Debug.Log(“hit go (all):” + goHitall.name + " depth:" + hit.distance);
}
Ouputs:
hit go (all):Cube depth:7.706799
hit go (all):Cylinder depth:10.10429
Here I would expect to get 2 points for each gameobject.
Situation:
[71865-raycast-1colonly.png|71865]*
What can I do about this? Thank you
*

2

What you could try is calling an additional RaycastAll in the opposite direction, and reversing the resulting array. This will give you 2 arrays with indexes corresponding to the same object.

Demo

Disclaimer: I’ve offset the rays by 0.25 and -0.25 on the Y-axis so it’s easier to visualize. Please note that even those the console output shows incorrect/rounded figures of 0.3 and -0.3, this is [just the behavior of the Unity Editor][1].

  • The green ray move left to right, and is considered the forward “enter” direction.
  • The red ray moves right to left, and is considered the reverse “exit” direction.
  • Edit: I have added small arrows and ray hit points using Photoshop for clarity.

[72025-screen-shot-2016-06-12-at-94024-pm.png*_|72025]

using UnityEngine;
using System.Collections;

public class RaycastExample : MonoBehaviour
{
	bool logged;

    void Update()
    {
        // Raycast Origins
        Vector3 enterRayOrigin = new Vector3(-6, 0.25f, 0);
        Vector3 exitRayOrigin = new Vector3(6, -0.25f, 0);

        // Show rays in scene view
        Debug.DrawRay(enterRayOrigin, Vector3.right * 12f, Color.green);
        Debug.DrawRay(exitRayOrigin, Vector3.left * 12f, Color.red);

        // Actually cast rays
        RaycastHit[] enterHits = Physics.RaycastAll(enterRayOrigin, Vector3.right, 12f);
        RaycastHit[] exitHits = Physics.RaycastAll(exitRayOrigin, Vector3.left, 12f);

        // Reverse the second raycast so indexes between the
        // two will correspond to the same object.
        System.Array.Reverse(exitHits);

        // For demonstration, log out the hits one time.
        if (!logged)
        {
            for (int i = 0; i < enterHits.Length; i++)
            {
                RaycastHit enter = enterHits*;*

RaycastHit exit = exitHits*;*

string enterName = enter.collider.gameObject.name;
string exitName = exit.collider.gameObject.name;

Debug.Log("Hit entering: " + enterName + " at: " + enter.point);
Debug.Log("Hit exiting: " + exitName + " at: " + exit.point);
}
logged = true;
}
}
}
_[1]: http://answers.unity3d.com/questions/958686/raycast-hit-point-rounding-itself.html*_
_