// Create a JointDrive, configure it and assign the JointDrive to
// the zDrive element of a configurable joint.

function Start() {
var joint : ConfigurableJoint = gameObject.AddComponent(ConfigurableJoint);
joint.targetPosition = Vector3(0,0,-10);

var drive : JointDrive = JointDrive();
drive.mode = JointDriveMode.Position;
drive.positionSpring = 20;

joint.zDrive = drive;
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
void Start() {
ConfigurableJoint joint = gameObject.AddComponent<ConfigurableJoint>();
joint.targetPosition = new Vector3(0, 0, -10);
JointDrive drive = new JointDrive();
drive.mode = JointDriveMode.Position;
drive.positionSpring = 20;
joint.zDrive = drive;
}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

def Start():
joint as ConfigurableJoint = gameObject.AddComponent[of ConfigurableJoint]()
joint.targetPosition = Vector3(0, 0, -10)
drive as JointDrive = JointDrive()
drive.mode = JointDriveMode.Position
drive.positionSpring = 20
joint.zDrive = drive