I have a object that moves at a variable speed. It can reach from 0 speed units up to N speed units.
I'm lerping the camera angle to rotate and look at the object smoothly and nice, like this:
camera.eulerAngles = Vector3.Lerp(initialAngle, finalAngle, speed / N);
The problem is when the object collides and the velocity decrease instantaneously to 0, the lerp happens very abruptly.
How can I make it handle this situation? I'd like a fast interpolation in this case, but no instantaneous like I'm seeing.
You can clamp the speed delta per iteration:
private const float MAX_DELTA = 0.1F;
private float prevSpeed;
private void UpdateRotation() {
float currentSpeed = Mathf.Clamp(speed, prevSpeed - MAX_DELTA, prevSpeed + MAX_DELTA);
camera.eulerAngles = Vector3.Lerp(initialAngle, finalAngle, currentSpeed / N);
prevSpeed = currentSpeed;
}
Related
Good day,
I'd like to program a constantly moving ball (object3) being passed between two stationary objects (object1, object2), with the ability to set the max height Y of the pass trajectory dynamically.
What would you argue is the best way to program the ball physics for this concept?
I've looked at using addForce on a default sphere w/ a rigidbody. It seems like there should be an equation that expresses the trajectory of a pass of object3 from object1's x to object2's x... at a known, given speed, with a known, set mass, and a known gravity environment.
However, currently I have a Vector3.Lerp interpolating the ball between the two objects on each FixedUpdate() with t expressed as:
`(Mathf.Sin(speed * Time.time) + 1.0f) / 2.0f;`
It works and all, but with this approach, it seems there's no clear way to add height to the trajectory of the ball path. I've considered adding the height to the Y value in object2 until the ball is half way there, and then setting it back to the original Y position... but it just feels wrong! Thoughts?
Thanks!
Okey so if I understand you correctly currently you are doing
privte void FixedUpdate()
{
var factor = (Mathf.Sin(speed * Time.time) + 1.0f) / 2.0f;
object1.MovePosition(Vector3.Lerp(object2.position, object3.position, factor));
}
which moves the ball pingpong between object1 and object2 position but only planar.
Assuming for now the objects will only be moving within the XZ plane and never have different Y position in order to rather get a curve with height you could treat the separatly:
- Interpolate between both positions as before
- Separately calculate the Y position with sinus or any other mathematical curve function - for realistic physics probably rather a parabola actually
Could look somhow like
public class Example : MonoBehaviour
{
public Rigidbody object1;
public Transform object2;
public Transform object3;
// adjust in the Inspector
public float speed = 1;
public float Amplitude = 0;
// Just for debug
[Range(0, 1)] [SerializeField] private float linearFactor;
[SerializeField] private float yPosition;
private void FixedUpdate()
{
// This always returns a value between 0 and 1
// and linearly pingpongs forth and back
linearFactor = Mathf.PingPong(Time.time * speed, 1);
// * Mathf.PI => gives now a value 0 - PI
// so sinus returns correctly 0 - 1 (no need for +1 and /2 anymore)
// then simply multiply by the desired amplitude
var sinus = Mathf.Sin(linearFactor * Mathf.PI);
yPosition = sinus * Amplitude;
// As before interpolate between the positions
// later we will ignore/replace the Y component
var position = Vector3.Lerp(object2.position, object3.position, linearFactor);
object1.MovePosition(new Vector3(position.x, yPosition, position.z));
}
}
You could optionally also try and add some dumping in the Y direction in order to make the vertical movement more realistic (slow down when reaching the peak). I tried a bit using inverted SmoothStep like
// just for debug
[Range(0, 1)] [SerializeField] private float dampedSinusFactor;
[Range(0, 1)] [SerializeField] private float linearFactor;
[SerializeField] private float yPosition;
private void FixedUpdate()
{
// Use two different factros:
// - a linear one for movement in XZ
// - a smoothed one for movement in Y (in order to slow down when reaching the peak ;) )
linearFactor = Mathf.PingPong(Time.time * speed, 1);
dampedSinusFactor = InvertSmoothStep(linearFactor);
// * Mathf.PI => gives now a value 0 - PI
// so sinus returns correctly 0 - 1 ()
// then simply multiply by the desired amplitude
var sinus = Mathf.Sin(dampedSinusFactor * Mathf.PI);
yPosition = sinus * Amplitude;
// later we will ignore/replace the Y component
var position = Vector3.Lerp(object2.position, object3.position, linearFactor);
object1.position = new Vector3(position.x, yPosition, position.z);
}
// source: https://stackoverflow.com/a/34576808/7111561
private float InvertSmoothStep(float x)
{
return x + (x - (x * x * (3.0f - 2.0f * x)));
}
However for slow movements this looks a bit strange yet. But you can come up with any other maths curve that results in the expected behavior for x=[0,1] ;)
I've created a simple pendulum in Unity - GameObject with Rigidbody and Hinge Joint components. I've set both drag ang angular drag to 0. With starting position at 90 degrees I'd expect the pendulum to swing back and forth from 90 to -90 degrees. However, that's not the case - the amplitude decays very quickly, but for small angles the pendulum looks like it's never going to stop.
My question is: How should I configure hinge joints in order to achieve full control over physics and forces that resist motion? My goal is to have physics simulation as precise as it's possible, even at the cost of performance.
I've already tried to reduce time intervals for fixed step and increased solver iterations - none of these worked out.
Why do I need it? I'm planning to design a control system for multiple inverted pendulum on a cart. I have a mathematical model of my pendulum implemented in Matlab and I wanted to verify it using a simple model in Unity (because in that case I adjust all parameters, initial conditions etc. and the physics engine is calculating everything for me). If it turns out the physics engine that is backing Unity isn't reliable enough, what other software would you recommend me?
My understanding is that due to the way Unity's physics operates, there can be a loss of kinetic energy over time in this sort of pendulum motion if you only use a hinge joint. Basically, if you want an accurate pendulum simulation, you have to bypass the physics engine and implement it directly.
There is a very good post on the gamedev stackexchange originally posted by MLM about how to implement a more accurate pendulum simulation in Unity, which I have pasted below.
I thought this would be a relatively simple problem to solve but I spent a couple days trying to figure out how the heck to simulate pendulum movement. I didn't want to cheat and just change the x,y position based on sin(theta) and cos(theta) curves. Instead I wanted to deal with the two forces that are applied in real life, Gravity and Tension. The main piece I was missing was centripetal force.
The Pendulum (mathematics) wikipedia page has a great animation(below, on left) explaining the pendulum motion. You can see my result(on right) strikingly similar to that diagram
The "bob" is the swinging object and the "pivot" is the origin/root.
I also found this article and diagram(below) pretty helpful:
Theta equals the angle between the rope and the direction of gravity.
When the bob is on the left or right the tension equals:
The reason the tension force is greater as the bob approaches equilibrium point(middle) is because of centripetal force:
So the overrall tension formula looks like as the bob swings is:
There are two forces in the pendulum system:
Gravity
GravityForce = mass * gravity.magnitude
GravityDirection = gravity.normalized
Tension
TensionForce = (mass * gravity * Cos(theta)) + ((mass * velocityTangent^2)/ropeLength)
TensionDirection = ropeDirection = bob to pivot
Just apply gravity to your object like you would for a normal object and then apply the tension. When you apply the forces, just multiply the force by the direction and deltaTime.
Below is the Pendulum.cs script(also as a GitHub Gist). It works quite well but there is some rounding error drift if you leave it for a while (doesn't return to exactly same position).
The script works in 3D but of course a pendulum only swings in a 2D plane. It also works with gravity in any direction. So for example, if you invert the gravity the pendulum works upside down. Edit->Project Settings->Physics->Gravity
It is very important to have a consistent relatively small deltaTime when updating the pendulum so that you do not bounce around the curve. I am using the technique found in this article, FIX YOUR TIMESTEP! by Glenn Fiedler to accomplish this. Check the Update() function below to see how I implemented it.
Also as a GitHub Gist
using UnityEngine;
using System.Collections;
// Author: Eric Eastwood (ericeastwood.com)
//
// Description:
// Written for this gd.se question: http://gamedev.stackexchange.com/a/75748/16587
// Simulates/Emulates pendulum motion in code
// Works in any 3D direction and with any force/direciton of gravity
//
// Demonstration: https://i.imgur.com/vOQgFMe.gif
//
// Usage: https://i.imgur.com/BM52dbT.png
public class Pendulum : MonoBehaviour {
public GameObject Pivot;
public GameObject Bob;
public float mass = 1f;
float ropeLength = 2f;
Vector3 bobStartingPosition;
bool bobStartingPositionSet = false;
// You could define these in the `PendulumUpdate()` loop
// But we want them in the class scope so we can draw gizmos `OnDrawGizmos()`
private Vector3 gravityDirection;
private Vector3 tensionDirection;
private Vector3 tangentDirection;
private Vector3 pendulumSideDirection;
private float tensionForce = 0f;
private float gravityForce = 0f;
// Keep track of the current velocity
Vector3 currentVelocity = new Vector3();
// We use these to smooth between values in certain framerate situations in the `Update()` loop
Vector3 currentStatePosition;
Vector3 previousStatePosition;
// Use this for initialization
void Start () {
// Set the starting position for later use in the context menu reset methods
this.bobStartingPosition = this.Bob.transform.position;
this.bobStartingPositionSet = true;
this.PendulumInit();
}
float t = 0f;
float dt = 0.01f;
float currentTime = 0f;
float accumulator = 0f;
void Update()
{
/* */
// Fixed deltaTime rendering at any speed with smoothing
// Technique: http://gafferongames.com/game-physics/fix-your-timestep/
float frameTime = Time.time - currentTime;
this.currentTime = Time.time;
this.accumulator += frameTime;
while (this.accumulator >= this.dt)
{
this.previousStatePosition = this.currentStatePosition;
this.currentStatePosition = this.PendulumUpdate(this.currentStatePosition, this.dt);
//integrate(state, this.t, this.dt);
accumulator -= this.dt;
this.t += this.dt;
}
float alpha = this.accumulator/this.dt;
Vector3 newPosition = this.currentStatePosition*alpha + this.previousStatePosition*(1f-alpha);
this.Bob.transform.position = newPosition; //this.currentStatePosition;
/* */
//this.Bob.transform.position = this.PendulumUpdate(this.Bob.transform.position, Time.deltaTime);
}
// Use this to reset forces and go back to the starting position
[ContextMenu("Reset Pendulum Position")]
void ResetPendulumPosition()
{
if(this.bobStartingPositionSet)
this.MoveBob(this.bobStartingPosition);
else
this.PendulumInit();
}
// Use this to reset any built up forces
[ContextMenu("Reset Pendulum Forces")]
void ResetPendulumForces()
{
this.currentVelocity = Vector3.zero;
// Set the transition state
this.currentStatePosition = this.Bob.transform.position;
}
void PendulumInit()
{
// Get the initial rope length from how far away the bob is now
this.ropeLength = Vector3.Distance(Pivot.transform.position, Bob.transform.position);
this.ResetPendulumForces();
}
void MoveBob(Vector3 resetBobPosition)
{
// Put the bob back in the place we first saw it at in `Start()`
this.Bob.transform.position = resetBobPosition;
// Set the transition state
this.currentStatePosition = resetBobPosition;
}
Vector3 PendulumUpdate(Vector3 currentStatePosition, float deltaTime)
{
// Add gravity free fall
this.gravityForce = this.mass * Physics.gravity.magnitude;
this.gravityDirection = Physics.gravity.normalized;
this.currentVelocity += this.gravityDirection * this.gravityForce * deltaTime;
Vector3 pivot_p = this.Pivot.transform.position;
Vector3 bob_p = this.currentStatePosition;
Vector3 auxiliaryMovementDelta = this.currentVelocity * deltaTime;
float distanceAfterGravity = Vector3.Distance(pivot_p, bob_p + auxiliaryMovementDelta);
// If at the end of the rope
if(distanceAfterGravity > this.ropeLength || Mathf.Approximately(distanceAfterGravity, this.ropeLength))
{
this.tensionDirection = (pivot_p - bob_p).normalized;
this.pendulumSideDirection = (Quaternion.Euler(0f, 90f, 0f) * this.tensionDirection);
this.pendulumSideDirection.Scale(new Vector3(1f, 0f, 1f));
this.pendulumSideDirection.Normalize();
this.tangentDirection = (-1f * Vector3.Cross(this.tensionDirection, this.pendulumSideDirection)).normalized;
float inclinationAngle = Vector3.Angle(bob_p-pivot_p, this.gravityDirection);
this.tensionForce = this.mass * Physics.gravity.magnitude * Mathf.Cos(Mathf.Deg2Rad * inclinationAngle);
float centripetalForce = ((this.mass * Mathf.Pow(this.currentVelocity.magnitude, 2))/this.ropeLength);
this.tensionForce += centripetalForce;
this.currentVelocity += this.tensionDirection * this.tensionForce * deltaTime;
}
// Get the movement delta
Vector3 movementDelta = Vector3.zero;
movementDelta += this.currentVelocity * deltaTime;
//return currentStatePosition + movementDelta;
float distance = Vector3.Distance(pivot_p, currentStatePosition + movementDelta);
return this.GetPointOnLine(pivot_p, currentStatePosition + movementDelta, distance <= this.ropeLength ? distance : this.ropeLength);
}
Vector3 GetPointOnLine(Vector3 start, Vector3 end, float distanceFromStart)
{
return start + (distanceFromStart * Vector3.Normalize(end - start));
}
void OnDrawGizmos()
{
// purple
Gizmos.color = new Color(.5f, 0f, .5f);
Gizmos.DrawWireSphere(this.Pivot.transform.position, this.ropeLength);
Gizmos.DrawWireCube(this.bobStartingPosition, new Vector3(.5f, .5f, .5f));
// Blue: Auxilary
Gizmos.color = new Color(.3f, .3f, 1f); // blue
Vector3 auxVel = .3f * this.currentVelocity;
Gizmos.DrawRay(this.Bob.transform.position, auxVel);
Gizmos.DrawSphere(this.Bob.transform.position + auxVel, .2f);
// Yellow: Gravity
Gizmos.color = new Color(1f, 1f, .2f);
Vector3 gravity = .3f * this.gravityForce*this.gravityDirection;
Gizmos.DrawRay(this.Bob.transform.position, gravity);
Gizmos.DrawSphere(this.Bob.transform.position + gravity, .2f);
// Orange: Tension
Gizmos.color = new Color(1f, .5f, .2f); // Orange
Vector3 tension = .3f * this.tensionForce*this.tensionDirection;
Gizmos.DrawRay(this.Bob.transform.position, tension);
Gizmos.DrawSphere(this.Bob.transform.position + tension, .2f);
// Red: Resultant
Gizmos.color = new Color(1f, .3f, .3f); // red
Vector3 resultant = gravity + tension;
Gizmos.DrawRay(this.Bob.transform.position, resultant);
Gizmos.DrawSphere(this.Bob.transform.position + resultant, .2f);
/* * /
// Green: Pendulum side direction
Gizmos.color = new Color(.3f, 1f, .3f);
Gizmos.DrawRay(this.Bob.transform.position, 3f*this.pendulumSideDirection);
Gizmos.DrawSphere(this.Bob.transform.position + 3f*this.pendulumSideDirection, .2f);
/* */
/* * /
// Cyan: tangent direction
Gizmos.color = new Color(.2f, 1f, 1f); // cyan
Gizmos.DrawRay(this.Bob.transform.position, 3f*this.tangentDirection);
Gizmos.DrawSphere(this.Bob.transform.position + 3f*this.tangentDirection, .2f);
/* */
}
}
More glamour shots:
Set the maxAngularVelocity on your Rigidbody to Mathf.Infinity.
I know this topic is 9 months old, but I have been banging my head against a wall recently because of this issue. For some reason the Unity developers thought it was a good idea to limit the maximum rotational velocity of rigidbodies to 7 radians per second! That's just a little over one revolution per second, which is way too low for any application that requires physcal accuracy. And on top of that, the property isn't visible in the inspector, or the physics settings!
I hope this will help you (if you haven't figured it out on your own yet) and anyone else who might be fighting with this problem in the future, cheers!
tl;dr Moving my game from Processing to Unity. Code responsible for grappling by manually changing the player's velocity doesn't work even though it's basically copy/pasted.
Hi, I've been working on a project of mine over the summer on Processing, and last week I decided to translate it over to Unity.
What I'm having a problem with is the grapple/rope physics. It's supposed to essentially keep the player inside a circle (made by the endpoint of the rope and the length of the rope). When the player falls outside of this circle, the player's position is moved back to the edge of the circle and the player's velocity is set to tangent of the circle.
Decreasing the length of the rope while swinging is supposed to speed you up. (See Floating Point)
On Processing, it works perfectly just as described above, but when I basically copy/pasted the code into unity it loses momentum too quickly (always ends up stopping at the same angle on the other side the player started on). Here is the code for both (run on each physics frame):
(I've also made some images to describe the motion that both versions produce)
Processing
Code
(warning: bad and redundant)
physics update:
exists = (endPoint != null);
if(lgth<=0) lgth = 1;
if(exists) {
currentLength = phs.position.dist(endPoint);
if(currentLength > lgth) {
float angle = getAngle(endPoint, phs.position);
phs.addPosition(abs(currentLength - lgth), angle);
float angleBetween = getAngle(phs.position, endPoint);
PVector relativeVelocity = new PVector(phs.velocity.x + phs.position.x, phs.velocity.y + phs.position.y);
float displacement = angleBetween - 90;
Line l1 = lineFromTwoPoints(relativeVelocity, endPoint);
Line l2 = lineFromAngle(phs.position, displacement);
PVector pointToLerpTo = intersection(l1, l2);
if(pointToLerpTo!=null) {
phs.velocity.x = pointToLerpTo.x-phs.position.x;
phs.velocity.y = pointToLerpTo.y-phs.position.y;
}
else phs.velocity.mult(0);
}
}
when the player shortens the rope, speed increases:
if(exists) {
float newLgth = lgth-d;
float distance = getDistance(phs.position, endPoint);
if(distance > newLgth) {
float ratio = (distance-newLgth)/lgth;
phs.velocity.setMag(phs.velocity.mag()*(1+ratio));
}
lgth = newLgth;
}
Motion from Processing (good)
Player starts by moving downwards at left edge of rope circle. Doesn't lose speed and continues going around multiple times until gravity slows it down.
Unity
Code
both code blocks from above are handled in the same place here, under FixedUpdate() (problematic part seems to be the velocity section)
distance = Vector2.Distance(transform.position, endpoint);
if(connected && distance > length) {
//lerp position -> endpoint// keep gameObject within length of the rope
float posLerpAmount = (distance - length) / distance;
transform.position = Vector2.Lerp(transform.position, endpoint, posLerpAmount);
//'lerp' velocity -> endpoint// keep the velocity locked to the tangent of the circle around the endpoint
Vector2 relativeVelocity = GetComponent<Rigidbody2D>().velocity + (Vector2)transform.position;
Line l1 = Geometry.LineFromTwoPoints(relativeVelocity, endpoint);
Line l2 = Geometry.LineFromAngle(transform.position, Geometry.GetAngle(endpoint, transform.position) - 90);
if(!Geometry.AreParallel(l1, l2)) {
Vector2 pointToLerpTo = Geometry.Intersection(l1, l2) - (Vector2)transform.position;
GetComponent<Rigidbody2D>().velocity = pointToLerpTo;
}
else GetComponent<Rigidbody2D>().velocity = new Vector2(0, 0);
//increases the magnitude of the velocity based on how far the rope moved the object's position
float ratio = (distance - length) / length;
GetComponent<Rigidbody2D>().velocity *= 1 + ratio;
distance = length;
}
Motion from Unity (bad)
Player starts by moving downward at left edge of rope circle. Gains a little bit of speed from gravity, then will always stop 45 degrees on the other side where it started (regardless of starting speed), then slowly fall back down to the bottom of the circle.
If anyone needs me to explain the Geometry class (lines, intersections) then I can, but I think it's mostly self-explanatory. Otherwise, I think I explained this the best I could. Thanks in advance for any help.
(also, StackOverflow isn't letting me add the Unity2d tag so I guess I gotta settle for Unity3d)
I found out that Rigidbody2D.velocity.magnitude is not how far the object moves every physics update. This is what was causing the issue, because the Processing code was based off the velocity being added directly to the position every update.
To fix this, what I did was do the same geometry, but scale the velocity to the % of how much of the velocity was actually 'used' (it usually travels 2% of the actual velocity vector).
Here is the final code in Unity: (this time I'm showing the fill FixedUpdate(), with the irrelevant parts removed)
float lastMagnitude;
Vector2 lastPosition;
void FixedUpdate() {
float velocityMoved = Vector2.Distance(lastPosition, transform.position) / lastMagnitude;
Debug.Log(velocityMoved * 100 + "%"); //this is usually 2%
bool shortenedRope = false;
if(Input.GetButton("Shorten Rope")) {
shortenedRope = true;
length -= ropeShortenLength;
}
distance = Vector2.Distance(transform.position, endpoint);
if(connected && distance > length) {
//lerp position -> endpoint// keep gameObject within length of the rope
float posLerpAmount = (distance - length) / distance;
transform.position = Vector2.Lerp(transform.position, endpoint, posLerpAmount);
//'lerp' velocity -> endpoint// keep the velocity locked to the tangent of the circle around the endpoint
Vector2 adjustedVelocity = rigidbody.velocity * velocityMoved;
Vector2 relativeVelocity = adjustedVelocity + (Vector2)transform.position;
Line l1 = Geometry.LineFromTwoPoints(relativeVelocity, endpoint);
Line l2 = Geometry.LineFromAngle(transform.position, Geometry.GetAngle(endpoint, transform.position) - 90);
if(!Geometry.AreParallel(l1, l2)) {
Vector2 pointToLerpTo = Geometry.Intersection(l1, l2) - (Vector2)transform.position;
rigidbody.velocity = pointToLerpTo;
rigidbody.velocity /= velocityMoved;
}
else rigidbody.velocity = new Vector2(0, 0);
//'give back' the energy it lost from moving it's position
if(shortenedRope) {
float ratio = (distance - length) / length;
rigidbody.velocity *= 1 + ratio;
}
distance = length;
}
lastPosition = transform.position;
lastMagnitude = rigidbody.velocity.magnitude;
}
EDIT: Recently learned that it is better to use Time.deltaFixedTime instead of the variable I made velocityMoved, since Time.deltaFixedTime is already calculated.
I a new here and i try to start working with Unity Engine.
Could somebody explain me, how works Quaternion.Slerp? Because I want to rotate some object in different angles 90, 180 and 270. My code you can see below. Unfortunately when I add 180 degrees, object make crazy things and than put rotation to (0, 180, 180) for this game object. I would like to get (180,0,0)
public float speed = 0.1F;
private float rotation_x;
void Update()
{
if (Input.GetButtonDown("Fire1"))
{
rotation_x = transform.rotation.eulerAngles.x;
rotation_x += 180;
}
transform.rotation = Quaternion.Slerp(transform.rotation, Quaternion.Euler(rotation_x, transform.eulerAngles.y, transform.eulerAngles.z), Time.time * speed);
}
Most examples out there including Unity examples from their official website are using Lerp in the wrong way. They didn't even bother to describe how it works in the API documentation. They just starch it in the Update() function and call it a day.
Mathf.Lerp, Vector3.Lerp, and Quaternion.Slerp work by changing from one position/rotation to another with the t value(last parameter) being passed in.That t value is also know as time.
The min of the t value is 0f and the max is 1f.
I will explain this with Mathf.Lerp to make it easier to understand. The Lerp functions are all the-same for both Mathf.Lerp, Vector and Quaternion.
Remember that Lerp takes two values and returns values between them. If we have a value of 1 and 10 and we do Lerp on them:
float x = Mathf.Lerp(1f, 10f, 0f); will return 1.
float x = Mathf.Lerp(1f, 10f, 0.5f); will return 5.5
float x = Mathf.Lerp(1f, 10f, 1f); will return 10
As you can see, the t(0) returns the min of the number passed in, t(1) returns the max value passed in and t(0.5) will return mid point between the min and the max value. You are doing it wrong when you pass any t value that is < 0 or > 1. That code in you Update() function is doing just that. Time.time will increase every second and will be > 1 in a second, so you have problems with that.
It recommended to use Lerp in another function/Coroutine instead of the Updated function.
Note:
Using Lerp has a bad side of it when it comes to rotation. Lerp does not know how to rotate Object with the shortest path. So bear that in mind. For example, you have an Object with 0,0,90 position. Lets say you want to move the rotation from that to 0,0,120 Lerp can sometimes rotate left instead of right to reach that new position which means it take longer to reach that distance.
Let's say we want to make the rotation (0,0,90) from whatever the current rotation is. The code below will change the rotation to 0,0,90 in 3 seconds.
ROTATION OVER TIME:
void Start()
{
Quaternion rotation2 = Quaternion.Euler(new Vector3(0, 0, 90));
StartCoroutine(rotateObject(objectToRotate, rotation2, 3f));
}
bool rotating = false;
public GameObject objectToRotate;
IEnumerator rotateObject(GameObject gameObjectToMove, Quaternion newRot, float duration)
{
if (rotating)
{
yield break;
}
rotating = true;
Quaternion currentRot = gameObjectToMove.transform.rotation;
float counter = 0;
while (counter < duration)
{
counter += Time.deltaTime;
gameObjectToMove.transform.rotation = Quaternion.Lerp(currentRot, newRot, counter / duration);
yield return null;
}
rotating = false;
}
INCREMENTAL ANGULAR ROTATION OVER TIME:
And to just rotate the Object to 90 in z axis, the code below is a great example of that. Please understand there is a difference between moving Object to new rotational point and just rotating it.
void Start()
{
StartCoroutine(rotateObject(objectToRotate, new Vector3(0, 0, 90), 3f));
}
bool rotating = false;
public GameObject objectToRotate;
IEnumerator rotateObject(GameObject gameObjectToMove, Vector3 eulerAngles, float duration)
{
if (rotating)
{
yield break;
}
rotating = true;
Vector3 newRot = gameObjectToMove.transform.eulerAngles + eulerAngles;
Vector3 currentRot = gameObjectToMove.transform.eulerAngles;
float counter = 0;
while (counter < duration)
{
counter += Time.deltaTime;
gameObjectToMove.transform.eulerAngles = Vector3.Lerp(currentRot, newRot, counter / duration);
yield return null;
}
rotating = false;
}
All my examples are based on frame-rate of the device. You can use real-time by replacing Time.deltaTime with Time.delta but more calculation is required.
Before anything, you can't add 180 on euler angles like that, and that's mainly what is causing your problem. You'd better use quaternion directly instead, or work on the transform itself.
You can think of a quaternion as an orientation in space. In contrary to what have been said, I do recommend learning how to use them if you can. However, I don't recommend using euler angles at all... as they're suject to different writing conventions, and will fail sometimes. You can look at 'gimbal lock' if you want details about that.
Simply a slerp or lerp (standing for spherical linear interpolation, or linear interpolation respectively) is a way to interpolate (go from one orientation to another, by increasing t from 0 to 1, in a coroutine or anywhere else) between orientation A and B. The difference between the two is that the slerp is giving you the shortest path from A to B.
In the end, when t = 1, lerp(A,B,t) and slerp(A,B,t) will give you B.
In your case, if you want to instantly rotate an object in space to a specific orientation, I suggest you use Quaternion.AngleAxis which is the most forward way to describe mathematically a quaternion.
If you want to add a rotation, say 90° to you actual orientation (without animation between the two), you can do something like this :
transform.rotation *= Quaternion.AngleAxis(axis_of_rotation, angle)
or use transform.rotate (depending on the parameters, it can be a right multiply, or left : local, or world transform).
Programmers' answer is detailling how to animate your transform. But I do suggest you to investigate quaternion themselves, as it will give you global understanding of space transforms.
I have a sphere gameobject with 5 cubes placed on different points on the surface of the sphere. When a key is pressed, i would like the sphere to spin for a few seconds and then slowly stops on the first cube point on the cube and always keeping the same direction in rotation. The issue i am facing now is that, Quaternion.Slerp always takes the shortest path to the next cube which means sometimes the rotation direction is changed. Any ideas?
Thanks
You can easily handle the rotation as a Vector3 of Euler angles.
This way you can Linearly Interpolate the angles to the correct value. And you can use coterminal angles so that you're always interpolating to a higher value ( so no backwards rotations would occur ). After every rotational step you might want to normalize the angles to the 0, 360 range with this approach though.
Example Code :
using UnityEngine;
using System.Collections;
public class Rotation : MonoBehaviour {
public Transform firstPosition;
public Transform secondPosition;
public float rotationDuration = 3;
void Start () {
transform.rotation = firstPosition.rotation;
StartCoroutine(Rotate());
}
IEnumerator Rotate() {
var deltaTime = 0.0f;
var distance = firstPosition.rotation.eulerAngles - secondPosition.rotation.eulerAngles;
while(deltaTime < rotationDuration) {
var rotation = transform.rotation.eulerAngles;
rotation = firstPosition.rotation.eulerAngles + deltaTime/rotationDuration*distance;
transform.rotation = Quaternion.Euler(rotation);
deltaTime += Time.deltaTime;
yield return null;
}
transform.rotation = secondPosition.rotation;
}
}