Develop Reference

Using MoveRotation in Unity 3D to turn player towards a certain angle

I've been told that Rigidbody.MoveRotation is the best way in Unity 3D to rotate the player between fixed positions while still detecting hits. However, while I can move smoothly from fixed position to position with:
if (Vector3.Distance(player.position, targetPos) > 0.0455f) //FIXES JITTER
{
var direction = targetPos - rb.transform.position;
rb.MovePosition(transform.position + direction.normalized * playerSpeed * Time.fixedDeltaTime);
}
I can't find out how to rotate smoothly between fixed positions. I can rotate to the angle I want instantly using Rigidbody.MoveRotation(Vector3 target);, but I can't seem to find a way to do the above as a rotation.
Note: Vector3.Distance is the only thing stopping jitter. Has anyone got any ideas?

First of all MoveRotation doesn't take a Vector3 but rather a Quaternion.
Then in general your jitter might come from overshooting - you might be moving further than the distance between your player and target actually is.
You can avoid that bit by using Vector3.MoveTowards which prevents any overshooting of the target position like e.g.
Rigidbody rb;
float playerSpeed;
Vector3 targetPos;
// in general ONLY g through the Rigidbody as soon as dealing wit Physics
// do NOT go through transform at all
var currentPosition = rb.position;
// This moves with linear speed towards the target WITHOUT overshooting
// Note: It is recommended to always use "Time.deltaTime". It is correct also during "FixedUpdate"
var newPosition = Vector3.MoveTowards(currentPosition, targetPos, playerSpeed * Time.deltaTime);
rb.MovePosition(newPosition);
// [optionally]
// Note: Vector3 == Vector3 uses approximation with a precision of 1e-5
if(rb.position == targetPos)
{
Debug.Log("Arrived at target!");
}
Then you can simply apply this same concept also to rotation by going through the equivalent Quaternion.RotateTowards basically just the same approach
Rigidbody rb;
float anglePerSecond;
Quaternion targetRotation;
var currentRotation = rb.rotation;
var newRotation = Quaternion.RotateTowards(currentRotation, targetRotation, anglePerSecond * Time.deltaTime);
rb.MoveRotation(newRotation);
// [optionally]
// tests whether dot product is close to 1
if(rb.rotation == targetRotation)
{
Debug.Log("Arrived at rotation!");
}

You can go one step further and use a tweeting library to tween between rotations.
DOTween
With that you can call it like this:
rigidbody.DoRotate(target, 1f) to rotate to target in 1 second.
Or even add callbacks.
rigidbody.DoRotate(target, 1f).OnComplete(//any method or lambda you want)
If at some point you want to cancel the tween yuou can save it on a variable and then call tween.Kill();

So, you want to animate the rotation value over time until it reaches a certain value.
Inside the Update method, you can use the Lerp method to keep rotating the object to a point, but you will never really reach this point if you use Lerp. It will keep rotating forever (always closer to the point).
You can use the following:
private bool rotating = true;
public void Update()
{
if (rotating)
{
Vector3 to = new Vector3(20, 20, 20);
if (Vector3.Distance(transform.eulerAngles, to) > 0.01f)
{
transform.eulerAngles = Vector3.Lerp(transform.rotation.eulerAngles, to, Time.deltaTime);
}
else
{
transform.eulerAngles = to;
rotating = false;
}
}
}
So, if the distance between the current object angle and the desired angle is greater than 0.01f, it jumps right to the desired position and stop executing the Lerp method.

Unity Simple Character Controller Script not working as expected

Im scratching my head over this one, really cant figure it out.
Im trying to implement the player movement from this example:
https://www.youtube.com/watch?v=LNidsMesxSE
Starts at minute 4:25 and ends at minute 5:20
This script tries translating all that to unity.So I started all the way over from scratch and just want to make a simple movement script.
You can plug this into any Unity version, throw the script onto and object with a CharacterController component, add a child object with a mesh that will tilt, the main object will rotate around its Y axis and move.
I do recommend using a simple T pose character or atleast a long capsule so you can better see what is happening than when you would be using a cube to test this.
The weird glitches im having is that the object randomly spasms out even though im always only adding extremely small rotations and movements every frame. And 95% of the time it doesnt happen, so I havent been able to pinpoint exactly what is causing this.
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class CharacterMove : MonoBehaviour
{
public float speed = 200f;
public float rotationSpeed = 180f;
public float tiltFactor = 8f;
public bool normalizeVelocity = false;
CharacterController cc;
Vector3 velocity;
Transform armatureBody;
void Start()
{
cc = GetComponent<CharacterController>();
armatureBody = transform.GetChild(0);
}
void Update()
{
velocity = new Vector3(Input.GetAxis("Horizontal"), 0,
Input.GetAxis("Vertical"));
}
void FixedUpdate()
{
if ((velocity != Vector3.zero))
{
var ccVelocity = cc.velocity; // CharacterController velocity. This might be the problem, but without it I cannot rotate the object towards the actual forward velocity.
Quaternion toRotation;
toRotation = Quaternion.LookRotation(ccVelocity, Vector3.up);
transform.rotation = Quaternion.RotateTowards(transform.rotation, toRotation, rotationSpeed * Time.deltaTime);
if (Input.GetKey(KeyCode.S)) print("new toRotation: " + toRotation);
armatureBody.localEulerAngles = new Vector3(velocity.z * tiltFactor, 0, -velocity.x * tiltFactor); // Tilt Body towards velocity This causes the weirdest and most consistest twitching bugs when the tilt is backwards so the object is moving backwards, maybe because im using LookRotation to look backwards?
}
velocity = Quaternion.Euler(0, transform.eulerAngles.y, 0) * velocity; // forward is always forward
cc.SimpleMove(velocity * Time.deltaTime * speed);
}
}
This script does 4 things,
get the velocity from player input.
rotate the main Object(this script) towards the velocity
add tilt towards the velocity, to the child armatureBody, this is a t Pose character in my case.
move the main Object this script is on.
Any help would be appreciated.
I tried removing the vector3 != Zero check, I tried normalizing the vectors, and I tried using a different Quaternion rotation method, but all with the same faulty results.

Check in Update() if Input.forward > threshold if so rotate to velocity. Dont rotate to velocity when only going sideways or backwards, so we can now strafe sideways and walk backwards when standing still or run and rotate to our velocity with the AD keys when running.
void Update()
{
velocity = new Vector3(Input.GetAxis("Horizontal"), 0,
Input.GetAxis("Vertical"));
if (velocity.z > 0.2f)
{
forwardVelocityThreshold = true;
}
else forwardVelocityThreshold = false;
}
Then in our FixedUpdate() we check for that bool and apply the rotateToVelocity if true.
Adjust the following if statement:
if (ccVelocity != Vector3.zero && forwardVelocityThreshold)
{
toRotation = Quaternion.LookRotation(ccVelocity, Vector3.up);
transform.rotation = Quaternion.RotateTowards(transform.rotation, toRotation, rotationSpeed * Time.fixedDeltaTime);
}
Now it works as intended, I also changed the deltaTime to FixedDeltaTime as suggested by Voidsay in the comments, although I have heard conflicting things about this. Some say FixedUpdate always uses fixedDeltaTime even if you are using deltaTime, other say no, always use fixedDeltaTime in FixedUpdate.

How can I rotate an object to face a target?

My bat stays still in the air.
How can i check that the player, that is moving right below on x axis, comes from the left or right side relative to the bat?
public class Bat : MonoBehaviour
{
Player player;
void Start()
{
player = FindObjectOfType<Player>();
}
void Update()
{
if (transform.InverseTransformPoint(player.transform.position).x >= 0)
transform.rotation = new Quaternion(transform.rotation.x, 0f, transform.rotation.z, 0f);
else
transform.rotation = new Quaternion(transform.rotation.x, -180f, transform.rotation.z, 0f);
}
}
As you may notice i try to flip the the Bat so it actually looks at the player.

First, don't use new Quaternion(...); unless you absolutely, 100% know quaternions inside and out. For instance, having the w component be 0 results in zero effective rotation. Also, quaternions use unitless figures and not degrees for their components. See here for a nice visualization of what different quaternion values might look like, under Quaternion).
Second, your logic is weird because if the bat has zero (identity) rotation, and the player is on the left of the bat, then your logic tries to* flip the bat 180 degrees, so that the player is now on the right side of the bat.
Then, the next frame assuming the bat and player are still in the same positions, the logic says oh the player is on the right side, set the rotation to zero (identity) rotation, which is of course what it was in the first place. So basically, you would have the bat rotate 180 degrees again so that the player is once again on the left side of the bat.
And so, you could get into a situation where every frame, the bat would flip a complete 180. Definitely not desired.
* I'm assuming if you had used Quaternion.Euler(transform.eulerAngles.x, 0f, transform.eulerAngles.z) etc.
Instead of concerning with any of that, use Vector3.Cross to find the forward the bat should point so its right faces the player's position. Then, use Quaternion.LookRotation to set the rotation of the bat to point in that forward direction:
void Update()
{
Vector3 batRightDir = player.transform.position - transform.position;
Vector3 batForwardDir = Vector3.Cross(batRightDir, Vector3.up);
if (batForwardDir.sqrMagnitude == Vector3.zero)
{
// player above or below bat. do nothing?
return;
}
transform.rotation = Quaternion.LookRotation(batForwardDir);
}
If you have the player on a different z as the bat, this will cause the bat to rotate around the y axis accordingly, which is what you would want from a 3d game, and could be a neat effect for a 2d game if you want that kind of effect.
If you want it to ignore the z position of the player, you could zero out the z component of batRightDir...
void Update()
{
Vector3 batRightDir = player.transform.position - transform.position;
batRightDir.z = 0; // ignore Z differences between bat and player
Vector3 batForwardDir = Vector3.Cross(batRightDir, Vector3.up);
if (batForwardDir.sqrMagnitude == Vector3.zero)
{
// player above or below bat. do nothing?
return;
}
transform.rotation = Quaternion.LookRotation(batForwardDir);
}
or it may be more intuitive to branch as you were previously:
void Update()
{
Vector3 batRightDir = player.transform.position - transform.position;
if (batRightDir.x > 0)
{
transform.rotation = Quaternion.identity;
}
else if (batRightDir.x < 0)
{
transform.rotation = Quaternion.LookRotation(Vector3.back);
}
else
{
// player above or below bat. do nothing?
}
}

You can get the access to his Rigidbody and than call it.
If Rigidbody.velocity.x > 0 he is moving to the right. If it's <0 it's moving to the left. All is related to X axis of course.

How to make LookAt align the transform.up vector instead of transform.forward?

The problem is that i cannot make a script that makes the enemy rotate so that "up" is pointing against the player, (with that i mean so that it will come to the player with transform.up) And i have not found any working solution yet, (from what i can tell)
I am trying to make a small 2D game, just for my friends to play. What i have tried is making the enemy look at the player and then set the "z" rotation to the same as the "x" rotation and after that reset the "x" and "y" rotation (so that "up" is pointing at the player). But the enemy just goes straight up.
using UnityEngine;
public class Enemy : MonoBehaviour
{
public Transform Player; // The Transform of the Player that you can controll
public float MoveSpeed = 4; // How fast the enemy should go
void FixedUpdate()
{
transform.LookAt(Player);
transform.rotation = Quaternion.Euler(transform.rotation.x, 0, transform.rotation.x);
transform.rotation = Quaternion.Euler(0, 0, transform.rotation.z);
transform.position += transform.up * MoveSpeed * Time.deltaTime;
}
}
So what i want to happen is that the Enemy will move to the Player but the rotation part is not working and it just goes straight up in the air instead of following the player. I might just be stupid and have missed something simple...

By using
transform.rotation = Quaternion.Euler(transform.rotation.x, 0, transform.rotation.x);
transform.rotation = Quaternion.Euler(0, 0, transform.rotation.z);
both times you overwrite the rotation with new values additionally mixing Euler (Vector3) with Quaternion fields ... transform.rotation.x is not the pure rotation around the X-axis you see in the Unity inspector.
It depends a bit on how exactly you want the enemy rotated in the end but you could simply use Transform.RotateAround like
transform.LookAt(Player);
transform.RotateAround(transform.position, transform.right, 90);
LookAt by default results in a rotation such that transform.forward is pointing at the target, transform.right remains pointing right(ish) and transform.up remains pointing up(ish). So all you have to do is rotating around that local X-axis transform.right exactly 90° so now transform.forward points down instead and transform.up points at the target.
which results in
If you than also want to change the other axis you can still additionally rotate it around the local transform.up axis as well e.g. to flip the forward vector "upwards":
transform.LookAt(Player);
transform.RotateAround(transform.position, transform.right, 90);
transform.RotateAround(transform.position, transform.up, 180);
Is there actually a special reason why you are doing that in FixedUpdate and not rather in Update? FixedUpdate should only be used for Physics related stuff.

Unity3D - Make character moving forward nicely on a seesaw in a 2.5D runner game

What I want to do is to make a kind of 2.5D runner game in Unity, which the character's all three rotation axises are frozen and the position on Z axis is also frozen. I don't know how to make the character moving forward nicely on the seesaw. (I create the seesaw by using HingeJoint.)
I create a struct to detect the CapsuleCollider status by using Physics.Raycast() function and that works fine.
private struct ColliderStatus
{
public bool headed; //colliding up
public bool footed; //colliding down
public bool onPlane; //colliding down && the obstacle colliding does not have slope angle
public bool lefted; //colliding left
public bool righted; //colliding right
public bool inAir; //not colliding anything
}
I've tried these ways:
Add force on Rigidbody to move forward
//To move character rigidbody move forward automatically in runner game
//when the speed is lower than the minimum speed and it's on plane or in air.
if (rigidbody.velocity.x < minForwardSpeed && (colliderStatus.onPlane || colliderStatus.inAir))
{
rigidbody.AddForce(20f * Vector3.right);
}
//Add gravity to player
Vector3 gravityForce = new Vector3(0f, -gravityOnPlayer, 0f);
rigidbody.AddForce(gravityForce);
It doesn't work well because the character continue going up when it's on the seesaw though the seesaw starts to tilt. And there will be a velocity loss when the character fall to ground from a higher plane or after jumping and what it looks like is that the character will stunned for a little moment on the landing point and then begin to accelerate.
Use transform.Translate() to move forward && change the way of adding gravity
//Use transform.Translate() to move forward
//I recognize that by this way, there will be no velocity loss
//when the character falling down to the ground at the landing point
//If I don't use this condition, my character will stuck on the
//right vertical wall
if (!colliderStatus.righted)
{
transform.Translate(new Vector2(minForwardSpeed, 0f) * Time.deltaTime);
}
I don't know why I can't write like this since it will cause the velocity doesn't react correctly:
//Use transform.Translate() to move forward
if (!colliderStatus.righted && rigidbody.velocity.x < minForwardSpeed)
{
transform.Translate(new Vector2(minForwardSpeed, 0f) * Time.deltaTime);
}
To change the way of adding gravity, I use a function SlopeAngleVector() to calculate the slope vector the character is running on.
private Vector3 SlopeAngleVector()
{
Vector3 nextStepPositon = new Vector3(transform.position.x + 0.01f, transform.position.y, 0f);
Ray nextPosRay = new Ray(nextStepPositon, Vector3.down);
Ray nowPosRay = new Ray(transform.position, Vector3.down);
RaycastHit nextPosHit;
RaycastHit nowPosHit;
Vector3 slopeAngle = Vector3.zero;
Physics.Raycast(nowPosRay, out nowPosHit, 5f, obstaclesLayerMask);
if (Physics.Raycast(nextPosRay, out nextPosHit, 5f, obstaclesLayerMask))
{
slopeAngle = new Vector3(nextPosHit.point.x - nowPosHit.point.x, nextPosHit.point.y - nowPosHit.point.y, 0f).normalized;
}
return slopeAngle;
}
Then I add the gravity by calculate the gravity projection on the slope vector:
private void AddGravity()
{
Vector3 gravityForce = new Vector3(0f, -gravityOnPlayer, 0f);
//my character could be collided by the long vertical wall(colliderStatus.righted)
//so I set the condition as "!colliderStatus.footed"
//otherwise, I would use "colliderStatus.inAir"
if (!colliderStatus.footed)
{
gravityForce = new Vector3(0f, -gravityOnPlayer, 0f);
}
else
{
gravityForce = Vector3.Project(Vector3.down * gravityOnPlayer, SlopeAngleVector());
}
rigidbody.AddForce(gravityForce);
}
Now my character can slide down from the seesaw but it will keep going backwards. And it cannot make it through when on the low slope angle seesaw.
How to make a good behavior script for the runner on seesaw?

I'd suggest looking at some of the Unity standard asset character controllers, I believe they take slopes into account for their character movement. It may give you some ideas.
I'd also recommend modifying the way your code calculates the angle of the slope. The raycast hit will give you back a surface normal, you should then be able to use the Vector3.Cross to figure out the angle of the slope.
It'll be something like: Vector3.Cross(normal, (vector that points away from screen)).
You may need to tweak it to get it working correctly but this can give you the slope angle in one raycast. It may also eliminate potential issues of your move to position being just below the see saw.
As a general tip, try not to mix transform and rigidbody stuff together, if you want to move the rigidbody, move the rigidbody directly, not indirectly through the transform.