Develop Reference

Unity: How to limit the rotation of the z axis using Wheel Joint 2D?

I am creating a Jump and run game but you are driving with a car. I use the the Wheel Joint 2D collider and I am also able to jump. Here is my code for the movement:
void Update()
{
movement = Input.GetAxis("Horizontal");
if (Input.GetButtonDown("Jump") && IsGrounded())
{
carRb.velocity = new Vector2(carRb.velocity.x, jumpForce);
}
if (Input.GetButtonUp("Jump") && carRb.velocity.y > 0f)
{
carRb.velocity = new Vector2(carRb.velocity.x, carRb.velocity.y * 0.5f);
}
}
private void FixedUpdate()
{
backTire.AddTorque(-movement * speed * Time.fixedDeltaTime);
frontTire.AddTorque(-movement * speed * Time.fixedDeltaTime);
carRb.AddTorque(-movement * carTorque * Time.fixedDeltaTime);
}
It works just fine but when I am fast and jump I rotate completely around my own axis and I land on my head and can't move anymore. Therefore I want to limit the rotation of the z-axis to a certain degree so that it won't happen anymore. I looked up how to do it but it doesn't fit for my car-context. Do you have any idea?
I would be very grateful

You have multiple options to solve this:
Freeze the rotation axis on the rigibody (very limiting option)
Detect the faulty position as "upside-down + grounded" and respawn the vehicle after 2s
Forcefully rotate the vehicle back to normal rotation when it's grounded (not in air anymore, so you still allow flips in the air)
Limit the angle via script.
Last thing could be done like this:
Vector3 eulerRot = rb.rotation.eulerAngles; // read current rotation
eulerRot.z = Mathf.Clamp(eulerRot .y, minRotation, maxRotation); // clamp it only on z axis.
rb.rotation = Quaternion.Euler(eulerRot); // set clamped rotation

Unity 3D - Moving an Object around a circle circumference facing forward

I am using Unity3D to move the player around the circumference of a large circle facing inwards towards the centre at all times.
The following code works by using transform.forward
// Rotate the forward vector towards the target direction
Vector3 newDirection = Vector3.RotateTowards(transform.forward, targetDirection, singleStep, 0.0f);
and then I move the player sideways by using
characterController.Move(horizontalSpeed * transform.right * Time.deltaTime);
I have been stuck on how to get the player to move around the circumference but facing forward with the left of the player facing the centre of the circle.
My code is as follows
void Start()
{
characterController = GetComponent<CharacterController>();
}
void Update()
{
// Determine which direction to rotate towards
Vector3 targetDirection = GameObject.Find("Platforms").transform.position - transform.position;
// The step size is equal to speed times frame time.
float singleStep = 1 * Time.deltaTime;
// Rotate the forward vector towards the target direction by one step
Vector3 newDirection = Vector3.RotateTowards(transform.forward, targetDirection, singleStep, 0.0f);
// Draw a ray pointing at our target in
Debug.DrawRay(transform.position, newDirection*50, Color.red);
// Calculate a rotation a step closer to the target and applies rotation to this object
transform.rotation = Quaternion.LookRotation(newDirection);
CheckIfOnGround();
characterController.Move(velocity * Time.deltaTime);
}

Replace transform.forward to transform.left

How to rotate an object along all 3 axes with finger swipe?

I'm working on a simple AR Vuforia application. How can I implement the rotation of an object along all three axes with one finger swipe?
The code I'm currently using has one bug: the rotation of the object depends on its local axes. For example, if I look at the object from the front, everything works as it should, but if I look at the object from the back side, the finger swipe upwards makes it rotate downwards and vice versa.
Here is this script:
public float rotSpeed = 30f;
void OnMouseDrag()
{
float rotX = Input.GetAxis("Mouse X")*rotSpeed*Mathf.Deg2Rad;
float rotY = Input.GetAxis("Mouse Y")*rotSpeed*Mathf.Deg2Rad;
transform.Rotate(Vector3.up, -rotX);
transform.Rotate(Vector3.right, -rotY);
}
This is not what I need, how can I rotate the object according to the finger swipe direction regardless of the angle from which I look at it?
Update
A simple non-AR example, which may help you understand what I need is an iOS game "Space Frontier 2". After a successful launch of the rocket, it lands on the planet and you can rotate the planet with your finger swipe.
Here is the video demo: https://youtu.be/OiNPP1WNIAI

This works nice regardless of your object's rotation, and regardless of your camera position relative to the object:
public float rotSpeed = 30f;
void OnMouseDrag()
{
float rotX = Input.GetAxis("Mouse X") * rotSpeed;
float rotY = Input.GetAxis("Mouse Y") * rotSpeed;
Camera camera = Camera.main;
Vector3 right = Vector3.Cross(camera.transform.up, transform.position - camera.transform.position);
Vector3 up = Vector3.Cross(transform.position - camera.transform.position, right);
transform.rotation = Quaternion.AngleAxis(-rotX, up) * transform.rotation;
transform.rotation = Quaternion.AngleAxis(rotY, right) * transform.rotation;
}
Make sure your camera has the "MainCamera" tag, or assign the camera externally if necessary.

I do not have the exact code with me right now.
But if you did not update your point of view coordinates, this should be the expected result.
Consider a real ball with 2 colors, blue and red, separated vertically.
When you are in front of it, seeing only the blue side, stroking it up will make the blue side go up and the red side appear from the bottom.
Now move behind it, seeing only the red side, and stroke it up again.
The blue face will go down and appear from the bottom.
Unity applies physics to virtual objects the same way we interact with real objects.
So you need to consider your camera position with the object orientation when you apply movements to it.
You need to apply a transformation matrix to your movement based on your camera location related to the object origin orientation.
I hope this is clear enough to put you on tracks to fix it.

I think you have to somehow clamp the rotation to have the desired behaviour. I wrote a script recently to do just that. I did a little modification though.
public float rotSpeed = 30f;
float ClampAngle(float _angle, float _min, float _max)
{
if (_angle < 0f) _angle = 360 + _angle;
if (_angle > 180f) Mathf.Max(_angle, 360 + _min);
return Mathf.Min(_angle, _max);
}
USAGE:
void RotateGameObject()
{
float h = Input.GetTouch(0).deltaPosition.x * Time.deltaTime * rotSpeed*Mathf.Deg2Rad;
float v = Input.GetTouch(0).deltaPosition.y * Time.deltaTime * rotSpeed*Mathf.Deg2Rad;
Vector3 rot = transform.rotation.eulerAngles + new Vector3(-v, h, 0f);
//Change the y & z values to match your expected behaviour.
rot.x = ClampAngle(rot.x, -5f, 20f);
//Clamp rotation on the y-axis
rot.y = ClampAngle(rot.y, -20f, 20f);
transform.eulerAngles = rot;
}
See if that works and of course, try to play with the values.

Unity2D Enemy Patrol, weird sprite rotation

Needed help here, I've been following this tutorial about Enemy Patrolling, https://www.youtube.com/watch?v=KKU3ejp0Alg
The tutorial tell us to set 2 Empty Game Objects and the coordinates so the sprite will walk from one direction to another, the walking does working, however the rotation of the sprite became really weird, the 'Worm' sprite is suppose to move left and right now it change into facing upward
Please look at this image,
When moving from left to right
When moving from right to left
public Transform[] patrolPoints;
public float speed;
Transform currentPatrolPoint;
int currentPatrolIndex;
// Use this for initialization
void Start()
{
currentPatrolIndex = 0;
currentPatrolPoint = patrolPoints[currentPatrolIndex];
}
// Update is called once per frame
void Update()
{
transform.Translate(Vector3.up * Time.deltaTime * speed);
if (Vector3.Distance(transform.position, currentPatrolPoint.position) < .1f) {
if (currentPatrolIndex + 1 < patrolPoints.Length)
currentPatrolIndex++;
else
currentPatrolIndex = 0;
currentPatrolPoint = patrolPoints[currentPatrolIndex];
}
Vector3 patrolPointDir = currentPatrolPoint.position - transform.position;
float angle = Mathf.Atan2(patrolPointDir.y, patrolPointDir.x) * Mathf.Rad2Deg - 90f;
Quaternion q = Quaternion.AngleAxis(angle, Vector3.forward);
transform.rotation = Quaternion.RotateTowards(transform.rotation, q, 180f);
}
This is the code
Thank you

You can pass the optional parameter Space.World to your translation to move your object relative to world space instead of object space. That should prevent your object from rotating.
transform.Translate(Vector3.up * Time.deltaTime * speed, Space.World);
You can read more about it in the documentation.

You probably rotated the enemy sprite by 90 degrees. Try placing all your scripts into empty game object with no rotation, than place the enemy sprite as child of the empty game object and rotate as you need. This way your logic won't collide with your graphics.

Rotate GameObject on Z axis while moving forward

Currently I have the following code, and it works 100% for a 3D game, but I can't get it to work for a 2D game.
What it is supposed to do, is once the object gets to the waypoint, it is supposed to rotate towards the new waypoint. What is actually happening is that it is rotating around the x and y axis, and not the z axis. What can I do to make it only rotate on the z axis? The object is supposed to turn as it moves forward based on the turn speed. It shouldn't be an instant turn, unless the turnspeed is a high number. But anyways, again I ask how do I get this code to only roate on the z axis?
void Update () {
if(toWaypoint > -1){
Vector3 targetDir = wayPoints[toWaypoint].position - transform.position;
Vector3 newDir = Vector3.RotateTowards(transform.forward, targetDir, turnSpeed * Time.deltaTime, 0.0f);
transform.rotation = Quaternion.LookRotation(newDir);
}
if(!usePhysics && toWaypoint != -1){
transform.Translate(Vector3.forward * Time.deltaTime * speed);
next();
}
}

Look rotation is not dependable for 2D games as the forward axis is different. One workaround is to parent the sprite to an empty GameObject with the z axis (blue arrow) pointed in the direction that the sprite will be rotating.

Looks like you're using Unity3D, which leaves me wondering why you're messing around with the Z-axis in the first place if you're making a game in 2D editing mode. The Z-axis does literally nothing in that mode, unless you set your two axes to include it somehow. My suggestion to you is to switch to 2D editing if you haven't already, then use Vector2s instead of Vector3s.
Also, try using one of the other axes as your axis of rotation (transform.right or .up instead of .forward).

I found what I was looking for:
void Update () {
if(toWaypoint > -1){
Vector3 vectorToTarget = wayPoints[toWaypoint].position - transform.position;
float angle = Mathf.Atan2(vectorToTarget.y, vectorToTarget.x) * Mathf.Rad2Deg;
Quaternion q = Quaternion.AngleAxis(angle, Vector3.forward);
transform.rotation = Quaternion.Slerp(transform.rotation, q, Time.deltaTime * turnSpeed);
}
if(!usePhysics && toWaypoint != -1){
transform.Translate(Vector3.right * Time.deltaTime * speed);
next();
}
}