This is a top-down view but in 3D coordinates, I would like to instantiate and fire a bullet from the player's gun. This script is on a spawner object at the end of the barrel.

void Fire () {

        float speed = 80;

        GameObject projectile = Instantiate (bullet, transform.position, transform.rotation) as GameObject;

        projectile.GetComponent<Rigidbody>().AddForce(transform.forward * speed);
        coolDown += Time.time;

I also tried this but in this case the bullet always moves in a fixed direction (North) :

projectile.GetComponent<Rigidbody>().velocity = Vector3.forward * speed;

Bullet is an empty object and the actual bullet is it's child ( did that to overcome a rotation issue ), the problem is nomatter how high I turn up the speed the bullet travels very very slow. Both the parent and the bullet have Rigidbody.


1 Answer 1


Force = Mass * Acceleration, so in order to accelerate an object to 80 you'd have to apply a force of 80 * Mass for one second.

If you want to instantly accelerate the object to a set speed, you should pass ForceMode.VelocityChange into AddForce. That will instantly change the object's velocity to what you want.

projectile.GetComponent<Rigidbody>().AddForce(transform.forward * speed, ForceMode.VelocityChange);

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