Rotate/spin object 360 degrees over set time in coroutine

Hi there, I have been working on getting an object to rotate 360 degrees within a set time using a coroutine.

I am attempting to rotate the current Y transform 360 degrees, but seem to be encountering some issues that I thought were related to when the transform.eulerAngles.y goes over 360 and needs to be set back to 0, but it seems like that wasn't the root of my problems. As it is the object rotates many times around its y axis, rather than just a single time, and also doesn't finish where the y axis was when the rotation started. Any advice for how to approach this would be appreciated! Below is the code showing what I have attempted so far.

Code (CSharp):

1.     IEnumerator Rotate(float duration)
2.     {
3.         float i = 0;
4.         float yRotation;
5.         while (i < 1)
6.         {
7.             i += Time.deltaTime / duration;
8.             yRotation = Mathf.Lerp(transform.eulerAngles.y, transform.eulerAngles.y + 360, i);
9.             if (transform.eulerAngles.y > 360)
10.             {
11.                 transform.eulerAngles = new Vector3(transform.eulerAngles.x, transform.eulerAngles.y - 360, transform.eulerAngles.z);
12.             }
13.             transform.eulerAngles = new Vector3(transform.eulerAngles.x, yRotation, transform.eulerAngles.z);
14.             yield return null;
15.         }
16.     }

 

I think the problem is with the end value of your lerp. You increase transform.eulerAngles.y and add 360 to it, so the lerp will never reach its end. Try just 360 as the end value.

 

I agree with @Laperen
I would implement your coroutine as follow:

Code (CSharp):

1.     IEnumerator Rotate(float duration)
2.     {
3.         float startRotation = transform.eulerAngles.y;
4.         float endRotation = startRotation + 360.0f;
5.         float t = 0.0f;
6.         while ( t  < duration )
7.         {
8.             t += Time.deltaTime;
9.             float yRotation = Mathf.Lerp(startRotation, endRotation, t / duration) % 360.0f;
10.             transform.eulerAngles = new Vector3(transform.eulerAngles.x, yRotation, transform.eulerAngles.z);
11.             yield return null;
12.         }
13.     }

 

Thanks guys, I understand what I did wrong now!

 

@ericbegue's solution will work well, but make sure the set the transform value to the endRotation value following the while() loop, otherwise the final position won't precisely be where you want it (there would be a minor discrepancy based on the delta time that the final loop runs)

 

@rhysp
It's ok. In the last iteration, t will be greater than duration, therefore the last parameter of lerp will be more than one. That will make yRotation to have the same value as endRotation.

 

Read this anytime you're tempted to read a value from Euler angles and apply any logic to it. Euler angles are terrible - literally the only thing they're good for is letting a human type in rotation values.

Even if it works now, it's easy to imagine a tiny change in the future making this break, and giving you weird rotation bugs. Honestly, 95% of the rotation-related questions on this forum can be answered with a variation of "don't use Euler angles".

In this case, I would suggest using .AngleAxis and not use Euler angles at all. It might look like:

Code (csharp):

1. IEnumerator Rotate(float duration) {
2. Quaternion startRot = transform.rotation;
3.  float t = 0.0f;
4.         while ( t  < duration )
5.         {
6.             t += Time.deltaTime;
7.             transform.rotation = startRot * Quaternion.AngleAxis(t / duration * 360f, Vector3.right); //or transform.right if you want it to be locally based
8.             yield return null;
9.         }
10. transform.rotation = startRot;
11. }

 

Nice, thanks for posting this.
With some very slight changes, you could make a variation that accepts N degrees. and instead of setting transform rotation to the original rotation at the end you would just set it to the ending rotation.

 

This does not work, transform.eulerAngles changes everytime once you set it, because you use transform.eulerAngles.x,y values inside while, the resulting rotation is messed up.

The correct version should be;

Code (CSharp):

1.     IEnumerator Rotate(float duration)
2.     {
3.         Vector3 startRotation = transform.eulerAngles;
4.         float endRotation = startRotation.z + 360.0f;
5.         float t = 0.0f;
6.         while ( t  < duration )
7.         {
8.             t += Time.deltaTime;
9.             float yRotation = Mathf.Lerp(startRotation.z, endRotation, t / duration) % 360.0f;
10.             transform.eulerAngles = new Vector3(startRotation.x, yRotation, startRotation.z);
11.             yield return null;
12.         }
13.     }

 

I've tried the answers listed on this thread.
My issue is the coroutine doesn't end when t > duration but instead t keeps bouncing back to 0.
So the rotation never ends. Everytime t reaches more than 0 it loops back to 0 and i get an infinite rotation.

Any ideas?

 

Not without seeing your code no

 

If you're talking about the code above your comment, are you sure you just aren't starting another coroutine after the first one ends?

 

Well Mr Necro-Posting A Five-Year-Old Thread, it is probably best to start your own thread as forum rules dictate.

When you do, here is how to report your problem productively in the Unity3D forums:

http://plbm.com/?p=220

How to understand compiler and other errors and even fix them yourself:

https://forum.unity.com/threads/ass...3-syntax-error-expected.1039702/#post-6730855

If you post a code snippet, ALWAYS USE CODE TAGS:

How to use code tags: https://forum.unity.com/threads/using-code-tags-properly.143875/

Also, consider this:

You can also use this approach: To help gain more insight into your problem, I recommend liberally sprinkling Debug.Log() statements through your code to display information in realtime.

Doing this should help you answer these types of questions:

- is this code even running? which parts are running? how often does it run?
- what are the values of the variables involved? Are they initialized?

Knowing this information will help you reason about the behavior you are seeing.

If you are running a mobile device you can also see the console output. Google for how.