Use Virtual Camera In My Game Scene, but it always causes Scene changes, how to stop that?

Can you show me the inspector for the vcam that's doing this?

 

hmmm... looks like a precision issue. Can I see the inspector for the target group?

 

It's not a known issue. The CM scripts are ExecuteAlways and so they are running even in EditMode. If your group member positions are fluctuating then they will cause the vcam targeting the group to rotate slightly. Is your SummonPosition script ExecuteAlways?

 

Well, then I don't know why it's flickering like that. Can you create a small demo project where this happens and PM it to me?

 

Before you do that, maybe you could try with latest CM 2.6.0-preview release? Let me know if the issue is still present with that release.

 

Yes, I was wondering if there might be a connection. In fact his issue did get fixed; he sent me a test project in a private thread. It turns out that his problem is solved in CM 2.6.0-preview.3 (which isn't released yet).

If you'd like to wait for that release, that's fine. If you need a fix now and want to verify that it's the same issue, I could instruct you on how to patch CM 2.5.0 to test it out. Let me know.

 

You can patch CM 2.5.0 by first locating it in the package cache (an easy way to do that is to use the Unity inspector: select "Edit Script" on one of the Cinemachine behaviours and it will take you there).

Find CinemachineComposer.cs, and al line 217 add this line:

Code (CSharp):

1.                 rigOrientation = Quaternion.LookRotation(
2.                     rigOrientation * Vector3.forward, curState.ReferenceUp);
3.  

so that the new code looks like this:

Code (CSharp):

1.             if (deltaTime < 0 || !VirtualCamera.PreviousStateIsValid)
2.             {
3.                 // No damping, just snap to central bounds, skipping the soft zone
4.                 rigOrientation = Quaternion.LookRotation(
5.                     rigOrientation * Vector3.forward, curState.ReferenceUp);
6.                 Rect rect = mCache.mFovSoftGuideRect;
7.                 if (m_CenterOnActivate)
8.                     rect = new Rect(rect.center, Vector2.zero); // Force to center
9.                 RotateToScreenBounds(
10.                     ref curState, rect, curState.ReferenceLookAt,
11.                     ref rigOrientation, mCache.mFov, mCache.mFovH, -1);
12.             }
13.  

The caveat is that this patch is machine-specific, and will not be shared with other devs on your project unless they also make the patch.

If you try it, please let me know whether it fixes your issue.

 

Yes I did, but I was sleeping

At this point, the only thing I can think to do about this is for you to reproduce this issue in a small demo project that I can look at and debug.

 

Apparently, that is correct.

Thank you!

 

Yes, I can repro. Thanks for the upload! I'll look at it later today and try to figure out what's going on.

 

I looked at the scene, and found the issue. Unfortunately, I don't think it's the same issue as the one at the beginning of this thread.

In your test project, the scene is marked dirty if you click on the vcam to display the inspector. This is caused by the inspector wanting to show the game view composer guides. To do this it must repaint the game view, and since Unity 2019.1, the way to do this is to mark a game object dirty (even if it's not) and request a repaint. So the * marker on the scene is not telling the truth. You can prove this by saving the scene and then comparing it to the original. There is no difference.

So that really sucks. The good news is that there is another API call to repaint without dirtying the scene, so I will make a mod and this problem will disappear with the next CM release. Thank you very much for bringing this up!

In your original post, there is a difference in scene data, so it must be caused by something else. Can you make a repro project for that problem?

 

So yes, the procedural positioning code is doing dynamic transform calculations, and these are subject to tiny precision fluctuations - this is normal. When I run your scene, for example, I see the vcam's rotation fluctuating between 180 and -180. Invisible to the eye, but bitwise-different, so enough to trigger the "scene is dirty" logic.

The problem you are encountering is that you have enabled the "Save During Play" option of Cinemachine. This option is intended for camera designers to tweak vcam settings during play mode, and to have those changes carried back to the scene when play mode is stopped. Since Cinemachine can't detect which changes are wanted, and which changes are side-effects, it carries everything back - including changes to the transform. Those are the changes that are being saved in your case.

The solution is to simply disable that option:



You only have to disable it once - it is a global setting, and will be remembered. If and when you need this functionality to fine-tune your vcams during game play, you can turn it back on.

 

Without that option checked, I was not seeing the changed values in your new project when I exited play mode, or selected/deslected the vcam.

Save the scene once after exiting play mode. It should be stable after that.

 

Tell me the exact repro steps please, starting with "open the project in Unity x.x."

 

I am using Unity 2019.3.4f1, and CM 2.6.0-preview.3. Don't forget that CM 2.5.0 will show the little star on the scene, even if the content is unchanged - this has been fixed in 2.6.0-preview.3.