Bullet hole random rotation and size

Questions & Answers
1

Hi!
I’m new to the Unity and I’m learning how to make a basic FPS. Right now, I’m stuck at making bullet holes have random rotation along the normal.

My code:

public float Cooldown = 0.1f;
float CooldownRemaining = 0;
public float Range = 100.0f;
public float BulletHoleOffset = 1.0f;

public GameObject debrisPrefab;
public GameObject BulletHole;

// Use this for initialization
void Start () {
    
}

// Update is called once per frame
void Update () {
    CooldownRemaining -= Time.deltaTime;
    if (Input.GetMouseButton(0) && CooldownRemaining <= 0)
    {
        CooldownRemaining = Cooldown;
        Ray ray = new Ray(Camera.main.transform.position + Camera.main.transform.forward, Camera.main.transform.forward);
        RaycastHit hit;

        if(Physics.Raycast(ray, out hit, Range))
        {
            Vector3 hitPoint = hit.point;

            if (debrisPrefab != null)
            {
                //Particle effect
                Instantiate(debrisPrefab, hitPoint, Quaternion.FromToRotation(Vector3.up, hit.normal));
                //Bullet Hole
                Instantiate(BulletHole, hitPoint + (hit.normal * BulletHoleOffset), Quaternion.FromToRotation(Vector3.forward, hit.normal));
            }
        }
    }	
}

I’m stuck at “Quaternion.FromToRotation(Vector3.forward, hit.normal));” since I don’t know where to “plug” random rotation along the normal.
I managed to get a random rotation along particular axis, but it didn’t look good since it didn’t align with the normal.

Similar to above. How to achive random hole size?

Thanks in advance!

2

Use Transform.Rotate, note that oyu can pass a parameter that tells the method to use local space (which is always the default value if you don’t pass the parameter). Rotate random degrees around the local y-axis and you are set :slight_smile:
For the random scale, just pass a Vector3 composed of random values to the bullet Transform’s localScale variable.

//Bullet Hole
GameObject bulletHole =  Instantiate(BulletHole, hitPoint + (hit.normal * BulletHoleOffset), Quaternion.FromToRotation(Vector3.forward, hit.normal));
float randomRot = Random.Range(0f, 360f);
bulletHole.transform.Rotate(bulletHole.transform.right * randomRot);
float randomScale = Random.Range(0.5f, 1.5f);
bulletHole.transform.localScale = new Vector3(randomScale ,randomScale ,randomScale);

EDIT: CORRECTED CODE & SOLUTION (See comments below);

public float Cooldown = 0.1f;
      float CooldownRemaining = 0;
      public float Range = 100.0f;
      public float BulletHoleOffset = 1.0f;
      public GameObject debrisPrefab;
      public GameObject BulletHole;
      // Use this for initialization
      void Start () {
          
      }
      
      // Update is called once per frame
      void Update () {
          CooldownRemaining -= Time.deltaTime;
          if (Input.GetMouseButton(0) && CooldownRemaining <= 0)
          {
              CooldownRemaining = Cooldown;
              Ray ray = new Ray(Camera.main.transform.position + Camera.main.transform.forward, Camera.main.transform.forward);
              RaycastHit hit;
              if(Physics.Raycast(ray, out hit, Range))
              {
                  Vector3 hitPoint = hit.point;
                  if (debrisPrefab != null)
                  {
                      //Particle effect
                      Instantiate(debrisPrefab, hitPoint, Quaternion.FromToRotation(Vector3.up, hit.normal));
                      //Bullet Hole
                      GameObject bulletHole =  Instantiate(BulletHole, hitPoint + (hit.normal * BulletHoleOffset), Quaternion.identity) as GameObject;
       bulletHole.transform.rotation = Quaternion.FromToRotation(bulletHole.transform.up, hit.normal) * bulletHole.transform.rotation;
  float randomRot = Random.Range(0f, 360f);
       bulletHole.transform.Rotate(0, randomRot, 0);
       float randomScale = Random.Range(0.5f, 1.5f);
       bulletHole.transform.localScale = new Vector3(randomScale ,randomScale ,randomScale);
                  }
              }
          }    
      }