IngotGenerator.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

// ref. https://review-of-my-life.blogspot.jp/2017/11/throw-objects-and-move-aroud-with-laser-in-vr.html
// generate ingot and throw
public class IngotGenerator : MonoBehaviour {
	public Transform positionTarget;
	private static string INGOT_PATH = "Prefabs/ingot";
	private GameObject ingotGenerated;

	void Update () {
		SteamVR_Controller.Device device = SteamVR_Controller.Input ((int)GetComponent<SteamVR_TrackedObject> ().index);
		if (device.GetPressDown (SteamVR_Controller.ButtonMask.Trigger)) {
			// instantiate ingot at attached object's Transform
			if (positionTarget) {
				ingotGenerated = Instantiate ((GameObject)Resources.Load (INGOT_PATH), positionTarget.position, gameObject.transform.rotation * Quaternion.Euler(90,90,0));
			} else {
				ingotGenerated = Instantiate ((GameObject)Resources.Load (INGOT_PATH), gameObject.transform.position, gameObject.transform.rotation * Quaternion.Euler(90,90,0));
			}

			// grab ingot
			addFixedJoint ().connectedBody = ingotGenerated.GetComponent<Rigidbody> ();
		} else if (device.GetPressUp (SteamVR_Controller.ButtonMask.Trigger)) {
			// release ingot
			FixedJoint joint = gameObject.GetComponent<FixedJoint> ();
			if (joint != null) {
				joint.connectedBody = null;
				Destroy (joint);
				Rigidbody rigidbody = ingotGenerated.GetComponent<Rigidbody> ();
				rigidbody.velocity = device.velocity;
				rigidbody.angularVelocity = device.angularVelocity;
			}
			if (ingotGenerated != null) {
				Destroy (ingotGenerated, 3.0f);
			}
			ingotGenerated = null;
		}
	}

	private FixedJoint addFixedJoint() {
		FixedJoint joint = gameObject.AddComponent<FixedJoint> ();
		joint.breakForce = 20000;
		joint.breakTorque = 20000;
		return joint;
	}
}