Rigidbody jitter / lag when applying damping on Transposer

Hello everyone! I do not suppose anyone can help me with this issue I'm having?

I have a system where a Rigidbody that floats can be controlled via the keyboard (for example, accelerating it and slowing it down). I use multiple scripts to define characteristics such as a simple aerodynamics script, a floating script, movement script, etc. The camera I set up uses Cinemachine and follows and looks at the transform of the floating Rigidbody. However, when I do some damping on the Transposer, at high speeds, the object seems to start jittering. It is especially noticeable while it is not detecting the ground and flying high.

I have tried multiple solutions but none of these seem to work. These were: making sure all Rigidbody modifications were done in FixedUpdate, using different update methods in the CinemachineBrain, messing around with other settings in the Transposer and Composer, creating an empty GameObject that would follow the Rigidbody and setting Cinemachine to follow the empty GameObject instead, simplifying the system as much as possible by making it use one script and the basic Rigidbody drag instead of the aerodynamics script, and I even re-created my project as simple as possible to see if the problem was still there, but it was!

I might add that the Rigidbody I currently use has "Interpolate" on and I read that there was once an issue with Rigidbodies using "Interpolate" in Cinemachine. When I turned "Interpolate" off, the Rigidbody only started to jitter more vigorously. Where should I start trying to fix this issue?

Thank you!
Regards,
Andracer108

P.S. Attached, there are also my settings for Cinemachine. The fields surrounded with the red square brackets are the ones which make the jitter visible if anything larger than 0 is inputted. If any more info is needed, such as code, feel free to ask.

 

Thanks for the reply! I have prepared a simplified scene with a simplified system (I had to modify some of the code, but the problem does still show itself a bit). I will have a total of 6 scripts that I believe are needed for testing. I also made a basic explanation on each of them. Keep in mind, that in this simple scene (since I used just some Unity primitive objects and not a fully-fledged model), the jitter isn't that apparent. But, if you press the accelerate key (W) for a while, you will notice small jittering. This "lag" was more prominently shown when using a 3D model. If needed, I can try to record a small video in the actual project. Also, apologies in advance if it is something from my code and not from Cinemachine itself.

Attached please find the packaged simple scene. If there is something wrong with the package, please do inform me as this is actually the first time I had to export a package and send it to someone for a debug or code review. Thanks again!

 

Sorry! My mistake! I meant Transposer and NOT Composer. The problems only appear if I add damping in the X, Y, Z axes of the Transposer. By the way, any updates? Not trying to rush you, just curious if you have started working on it and if the problem is actually from my side.

 

Well, that seems to be true and thank you for offering a solution. But I actually need "Interpolate" as the vehicle in my actual project just jitters all over the place without it. I'm trying to find a solution to this as I'm typing this but I still need "Interpolate" for a slow down effect and it is much more efficient to use "Interpolate" than increasing the FixedTimestep. Increasing the FixedTimestep would also make the physics update more than they are supposed to even during the slow down effect. Are you sure that there is no other solution to my problem than this?

UPDATE: I have discovered that what makes the jitter visible is actually the motion blur post-processing effects that I have applied in my actual project. I did the same in the simple project I sent you and it actually does jitter. It doesn't jitter constantly, but as you turn or accelerate, the jitter is visible. Again, I would like your help as just setting "Interpolate" off does not solve the problem. If you want, I can send you what jitter is going on in my actual project and in the simple scene as a video.

 

Could you explain from where the irregular animation can be coming from or ideas of what it could be? The only "animation" that I had in my actual project is by rotating the transform to make the vehicle look like it's banking (I disabled this and the problem was still there).

Any ideas on how I can ensure a steady framerate? I will probably disable damping for now but I will probably want it in the future. So I would appreciate it if you were to offer me some ideas. Or is it as simple as decreasing the amount of content?

And yes, I would be glad to share the package again as an attachment. I have also added the post-processing stuff and added the 3D model I am using in my actual project which you can use to test as well.

 

Despite following all of your advice there is still some jitter visible in my actual project. I have tried everything to fix this including applying your solutions (and if I were to be honest, I would have liked more work to be done as I actually need motion blur and interpolation and I will only look at these as possible temporary workarounds). I also loaded up an official and similar Unity project from the 2017 version which uses Cinemachine. The setup in that project is similar to mine (for example, having the vehicle as an empty object with its children defining the model, collision, sensors, etc) and all the essential settings (Time settings, Quality settings, etc.) are the same and even the Cinemachine setup is the same and it showcases no problems whatsoever. What more steps can I try to fix this problem? Nothing else actually modifies the object.

 

The thing is, I already did that before. If you look at my package, you would see I have a script called BasicDrive and this pretty much eliminates the use of all the other scripts. The only things that would be needed for that script to work is the Rigidbody component with the drag values already set. I had tried that in my actual project but the problem was still there. I even removed all the unnecessary scripts (such as one controlling a particle system for thrusters) to test it out but, again, the problem was still there. I also removed the unnecessary child objects as well, I think at one point.

Regarding interpolation, if you scroll up to one of my previous replies, I said that I needed interpolation for an effect that I need in my game. The effect is slow motion. To efficiently do slow motion (or at least from what I read), you need to use Rigidbody interpolation as slowing down the time scale without interpolation will cause the physics to seem like they have "less resolution" and you could see the physics system work frame by frame, if the time scale is slowed down enough. Increasing the Fixed Timestep helped to solve the problem but that is extremely inefficient as it would require the CPU to work faster to compute the forces acting on the object, apart from the fact that the results would be inaccurate as even though the time scale is slowed down, the physics will work at an increased rate.

 

@Gregoryl Thanks for the info! In fact, I already had updated Cinemachine to version 2.2.0 from the Package Manager. For some reason though, it doesn't seem to be able to find a 2.2.2 version (do you know where I can get that by any chance?). Despite that, I decided to test your theory anyway and, when I enabled LateUpdate in the Brain, the camera updated normally without jitter (with Interpolation on)!

So, the problem could have potentially been Unity's actual Interpolation? I'll check if there is jitter when I enable damping on 2018.2. I'll reply with a status update so I can inform you if the problem is fixed or not.

Also, thank you for the note regarding Transform and Interpolation. I'll keep it in mind when developing.

 

Are you saying that I should wait until a stable 2.2.2 release to see if my problem is fixed? You see, I upgraded to the 2018.2 beta and tested it out, but the problem is still there in my actual project... as described before, I added damping to the transposer (to be exact, I added 0.05 damping on the Z axis) with an interpolated Rigidbody on SmartUpdate and when the object reaches high speeds, it starts to jitter a bit. I tested it out on LateUpdate as well, but the jitter was still there with the damping on.

 

Hi again! Sorry for necro-ing the thread but, I have updated Cinemachine to 2.2.7 (I'm not sure if there were other public versions before this because the Package Manager didn't show me there were any updates until today) and the problem is still there. When I apply damping on my Transposer, the vehicle starts jittering. After I updated, I even closed and opened Unity again but the problem is still there. I'm not sure what to do next now...

 

In my whole project, when interpolation on my vehicle is off, the vehicle starts jittering in a different way. The jittering is more aggressive and looks like heavy lag. To fix this, I turned on interpolation. When I have damping on and interpolation on, the vehicle doesn't do an occasional glitch, it just jitters constantly in a more subtle way but you can still see it when you compare it without the damping.

If you want, I can try to upload the actual project that I'm working on currently with some trimmed out parts to make the upload faster.

 

Yes, as we speak I am trying to prepare a project with my current hover car system and testing other things out too. I will upload it here sometime this week as I'm currently busy with the project itself and with other things.

 

Sorry it's taking a while. Again, I'm not having much chance... I'll try to create and upload a new test project this weekend. However, I do have a theory. I think it may be the 3D model itself that is causing the issue. I will test this out soon.

 

Hi. Just wanted to give you an update. I have re-created my project from scratch in a beta build of Unity. (The one with the Improved Prefabs) and I can confirm that the problem is not from the model or the Unity project itself. It has to be either from my own code or Cinemachine.

Also, I'm sorry for the delay. I will create for you a project with a proper Unity build for you to look at. I just wanted to do this little experiment first. I'll try to create it this week. If I cannot, I will post an update here again telling you if I found something new.

 

Hi guys,

I've been following this thread as I've had the same problems. In my project I have a similar setup - an interpolated rigidbody and Cinemachine camera that I'd like to put some damping values on.

Appreciate that it's not a simple fix and that frame rate issues throw a spanner in the works, but thought I'd share a very simple sample project I built to demonstrate the issue. Just a falling rigidbody sphere with interpolation on, and a camera with some damping on the Y.

My first time uploading a project, so not sure if this is the best way but here goes! Scream if it doesn't work. Hope it's helpful, and fully understand that it may not be quickly resolvable.

Cheers,

Bob.

 

Hey Bob! Thanks for uploading the project. You showed me up! Just kidding. Honestly, I'm kind of relieved to see that someone else is also experiencing these issues. I will download your project and see if I have the same issues on it too. Meanwhile, my test project is almost done. I will also upload it when I have finished it as well.

 

If I understand correctly, it's not currently possible to get smooth damped motion when tracking an interpolated rigidbody with a varying framerate. Is that correct @Gregoryl?

We experienced this issue (or a similar one) with one of our previous games, and the solution we used was to always do camera damping calculations (actually it was more of a spring calculation) in FixedUpdate, and then manually add the rigidbody interpolation to the camera in LateUpdate. The rigidbody interpolation is just the difference between the current LateUpdate and the previous FixedUpdate, so it looked something like this in the LateUpdate part...

camPosition = dampedCamPositionFromLastFixedUpdate + (rigidbodyPositionLateUpdate - rigidbodyPositionFixedUpdate);

It's possible I've overlooked something here, but I think that would smooth out the damped motion because the damping calculations would always be done at a consistent framerate?

 

Alright, so I have created my project. It's a very simple project with only a hovering object on a floor. It also has only 1 script in it that makes the hovering object move (by pressing W key) and "hover". Once you press and hold W, you will quickly see the damping problem and the object starts jittering.

 

Fair enough. The spring calculation we used was non-linear too, so technically it still allows for some error, but the error range was reduced to the very small difference between the sub-fixed-update linear interpolated position, and the position had it been calculated non-linearly at the same sub-fixed-update step. Which was imperceptible. Also, judder would only be visible on the background if it occurred, rather than on the object being tracked.

Out of interest, what would a more robust fix look like? I can't think of a way to get smooth motion without running the calculation at a consistent framerate.

 

Thank you @Gregoryl! Would you mind explaining further on how to get Cinemachine 2.2.8? I want to test things as well.

 

I am suggesting that

If the damping happens on a fixed framestep (which it has to), but the rendered frame lands between those steps, then it needs to interpolate? Otherwise there will be judder? I don't see any other option (when tracking an interpolated target).

 

Thanks for taking a look Gregory.

That test level still shows jittering if you set the aim to do nothing or set lookahead time to 0. Do you mean it's displaying both transposer damping jitter and lookahead jitter?

 

Hey! Just tried out the 2.2.8-preview.6 version and can confirm it seems to have resolved the main issue with damping on the camera body. Good stuff!

 

Hey guys, I know this is kind of an old post, but how would you deal with a rigidbody&rootmotion(set on animated physics) combo. Cinemachine appears smooth but it slightly jitters from time to time. I had also tried the 2.2.8-preivew.6 version and I don't see a big difference.

 

My English is not very good...
I had this problem.

Use Cinemachine and access the field body, transpose x, y , z :

Using Cinemachine;
then put:

public CinemachineFramingTransposer _anyname;

and in the code you access Damping:

_anyname.m_XDamping = 0.5f;
or
_anyname.m_YDamping = 0.5f;
or
_anyname.m_ZDamping = 0.5f;