Object.Instantiate

static function Instantiate (original : Object, position : Vector3, rotation : Quaternion) : Object

Description

Clones the object original and returns the clone.

Clones the object original, places it at position and sets the rotation to rotation, then returns the cloned object. This is essentially the same as using duplicate command (cmd-d) in Unity and then moving the object to the given location. If a game object, component or script instance is passed, Instantiate will clone the entire game object hierarchy, with all children cloned as well. All game objects are activated.
See Also: In depth Prefab Instantiate discussion

// Instantiates 10 copies of prefab each 2 units apart from each other
var prefab : Transform;
for (var i=0;i<10;i++) {
Instantiate (prefab, Vector3(i * 2.0, 0, 0), Quaternion.identity);
}

Instantiate is most commonly used to instantiate projectiles, AI Enemies, particle explosions or wrecked object replacements.

// Insantiate a rigidbody then set the velocity
var projectile : Rigidbody;
function Update () {
// Ctrl was pressed, launch a projectile
if (Input.GetButtonDown("Fire1")) {
// Instantiate the projectile at the position and rotation of this transform
var clone : Rigidbody;
clone = Instantiate(projectile, transform.position, transform.rotation);

// Give the cloned object an initial velocity along the current
// object's Z axis
clone.velocity = transform.TransformDirection (Vector3.forward * 10);
}
}

Instantiate can also clone script instances directly. The entire game object hierarchy will be cloned and the cloned script instance will be returned.

// Instantiate a prefab with an attached Missile script
var projectile : Missile;
function Update () {
// Ctrl was pressed, launch a projectile
if (Input.GetButtonDown("Fire1")) {
// Instantiate the projectile at the position and rotation of this transform
var clone : Missile;
clone = Instantiate(projectile, transform.position, transform.rotation);

// Set the missiles timeout destructor to 5
clone.timeoutDestructor = 5;
}
}

After cloning an object you can also use GetComponent to set properties on a specific component attached to the cloned object.

static function Instantiate (original : Object) : Object

Description

Clones the object original and returns the clone.

This function preserves the position and rotation of the cloned object. This is essentially the same as using duplicate command (cmd-d) in Unity. If the object is a Component or a GameObject then entire game object including all components will be cloned. If the game object has a transform all children are cloned as well. All game objects are activated after cloning them.
See Also: In depth Prefab Instantiate discussion

// Instantiates prefab when any rigid body enters the trigger.
// It preserves the prefab's original position and rotation.
var prefab : Transform;
function OnTriggerEnter () {
Instantiate (prefab);
}

Note that the Instantiate can clone any type of Object including scripts.