Projectile Hit Detection with Bullet Drop

Hello,
I am making a paintball game and am struggling with the shooting mechanics. I need my projectiles to be influenced by the worlds gravity, as well as travel a distance over time (i.e. not reach their target instantaneously). Also, I would like them to look realistic while in flight. With a simple Raycast, the hit detection functions very well, but the ray reaches the object it hits instantly, and does not account for gravity. Furthermore, I tried to apply a line renderer over the raycast to mimic the look of a paintball, but that attempt was unsuccessful.

My next, and current, approach is to fire a ray from the center of the player’s screen/camera, get the point hit, and instantiate a paintball prefab (rigidbody) at the barrel of the players gun, with its rotation facing the point returned from the ray. I then add a force to the paintball in that direction. From there, in a separate script for the paintball, I cast a ray in the Update method (I have also tried FixedUpdate) at a short length in front of the paintball object, and detect hits based on these rays. The problem is, this solution does not detect hits consistently/accurately.

My best guess is that the issue has to do with the fact that the projectile is moving at a significant velocity. I know that colliders have a issues when objects are moving at high velocities so I thought that using a raycast would fix the issue, but that is not the case. I am wondering if anyone has ever implemented a similar mechanic, and if I am on the right track, or if I need to completely rework my approach? Any guidance in the right direction would help immensely. Thanks in advance for your time and help!

Gun Script:

RaycastHit hit;
// Create a vector at the center of the camera's viewport
Vector3 rayOrigin = fpsCam.ViewportToWorldPoint(new Vector3(0.5f, 0.5f, 0.0f));

gunAudio.Play();

if (Physics.Raycast(rayOrigin, fpsCam.transform.forward, out hit, range)) {
    GameObject bullet = Instantiate(paintball, paintballSpawn.position,
        Quaternion.LookRotation(hit.point - paintballSpawn.position)) as GameObject;
    bullet.GetComponent<Rigidbody>().AddForce(bullet.transform.forward * paintVelocity);
}

Paintball Script:

void Update() {
    RaycastHit hit;
    Vector3 rayOrigin = gameObject.transform.position;

    Debug.DrawRay(rayOrigin, transform.forward, Color.blue);

    if (Physics.Raycast(rayOrigin, transform.forward, out hit, range)) {
        Debug.Log(hit.transform.tag);

        // Logic based on type of object hit

        Destroy(gameObject);
    }
}

Instead of using a raycast for bullet detection, I would recommend using an actual paintball prefab. Then, whenever the paintball gun is fired, have it spawn it at the tip and give it a velocity in the direction it is facing. Make sure to add a rigidbody and a trigger box collider to the paintball prefab, and give it a specific tag that you can then deal damage with a simple OnTriggerEnter. This allows for the gravity affect you want as well as the realistic bullet traveling.

If you have any more questions let me know! If this helped or solved your problem, please accept my answer. :slight_smile: