No active UnityEngine.XR.ARSubsystems.XRParticipantSubsystem is available

[AytoMaximo]

Hello!

I have an issue with AR CollaborationSession example. It worked fine on previous versions of ARFoundation/Unity, but now I can't get the ARParticipants' transforms (no prefab appears presenting the AR participant position).

The error message on the startup is:

No active UnityEngine.XR.ARSubsystems.XRParticipantSubsystem is available. Please ensure that a valid loader configuration exists in the XR project settings.

I don't know what kind of a setting I need to look for.

Also I'm having spam of this message:

[Technique] Error getting pose for participant anchor: CMMapNotAvailable

...and also having something like this:

2020-05-26 01:14:52.053698+0300 samples[9137:2247306] [GCKSession] Not in connected state, so giving up for participant [64A3896D] on channel [0].
2020-05-26 01:14:52.063293+0300 samples[9137:2247306] [GCKSession] Not in connected state, so giving up for participant [64A3896D] on channel [1].
2020-05-26 01:14:52.071056+0300 samples[9137:2247306] [GCKSession] Not in connected state, so giving up for participant [64A3896D] on channel [2].
2020-05-26 01:14:52.077876+0300 samples[9137:2247306] [GCKSession] Not in connected state, so giving up for participant [64A3896D] on channel [3].
2020-05-26 01:14:52.084187+0300 samples[9137:2247306] [GCKSession] Not in connected state, so giving up for participant [64A3896D] on channel [5].
2020-05-26 01:14:52.089913+0300 samples[9137:2247306] [GCKSession] Not in connected state, so giving up for participant [64A3896D] on channel [6].

However, the AR anchor works still fine.

Unity 2019.3.14f1, AR Foundation/ARKit 4.0 preview 3.

[tdmowrer]

As of 4.0.0-preview.3, ARFoundation now requires XR Management. See #484 (comment)

[AytoMaximo]

As of 4.0.0-preview.3, ARFoundation now requires XR Management. See #484 (comment)

I know about this, I have ARKit plugin activated, my AR is working. But I have an issue with XRParticipantSubsystem

[tdmowrer]

Looks like the ARKitLoader is indeed missing the XRParticipantSubsystem, so it never gets initialized. The fix will be in the next release. In the meantime, if you want to patch it locally, you can just add it to ARKitLoader.cs. You need a line like

CreateSubsystem<XRParticipantSubsystemDescriptor, XRParticipantSubsystem>(s_ParticipantSubsystemDescriptors, "ARKit-Participant");

in Initialize.

[AytoMaximo]

Looks like the ARKitLoader is indeed missing the XRParticipantSubsystem, so it never gets initialized. The fix will be in the next release. In the meantime, if you want to patch it locally, you can just add it to ARKitLoader.cs. You need a line like

CreateSubsystem<XRParticipantSubsystemDescriptor, XRParticipantSubsystem>(s_ParticipantSubsystemDescriptors, "ARKit-Participant");

in Initialize.

Thx, it's OK now!

[Daniellb12]

Hey Tim,

I'm currently running into these errors below which are preventing me from running scenes with my webcam. I've tried your hot fix above and it didn't work. Any help would be greatly appreciated.

[AdrianDot]

Hey Tom,

I'm currently running into these errors below which are preventing me from running scenes with my webcam. I've tried your hot fix above and it didn't work. Any help would be greatly appreciated.

I have the same four error-messages in my project and it works fine. Maybe the webcam isn't working for another reason? :)

[Daniellb12]

Hey Tim,
I'm currently running into these errors below which are preventing me from running scenes with my webcam. I've tried your hot fix above and it didn't work. Any help would be greatly appreciated.

I have the same four error-messages in my project and it works fine. Maybe the webcam isn't working for another reason? :)

What's your current Unity version? I've had 16 people try from unity version 2019.4.13f1, unity version 2020.110f1, 2020.21f1, across mac, windows, and Ubuntu.

Any help would be greatly appreciated. It works fine when pushed to device, just isn't able to access webcam for all 16 of those users.

[AdrianDot]

ARFoundation is only meant to be build on smartphones with either ARCore or ARKit. It's not working for pc webcams. Try Vuforia for your purpose :)

See: [https://stackoverflow.com/questions/61633914/how-to-use-pc-webcam-for-ar-foundation-in-unity]

[Daniellb12]

Interesting, because in early 2020 it was able to access my webcam without issue. Good to know for future reference, thanks Adrian.

[tdmowrer]

Unity has never provided webcam support for AR Foundation, but it is possible for someone outside of Unity to implement support. Perhaps you had another plugin in your project that implemented webcam support for AR Foundation?

[Daniellb12]

Maybe, haha I'll have to access my old archived files to see if I still have the old project file. Thanks for clearing up the confusion. That said, is there anyway to clear those warnings? Also, sorry for calling you Tom, for some reason I read Tom instead of Tim. My apologies.

[tdmowrer]

There's a button to clear messages in the console, but there is no way to suppress the message if that is what you mean.

[Daniellb12]

Yeah I meant suppressing the warning's or if there might be a hot fix to just get rid of them besides clearing my console since that singular line of code above didn't work. Besides that you two have answered my questions. Thanks guys.

[tdmowrer]

To clarify: the warnings are telling you that AR isn't going to work because the current platform is not supported by any of the packages you currently have installed. It does not impact any other functionality, so other than unwanted log messages, there is nothing to "fix". Are you suggesting a change to this behavior?

[boffipaolo]

Hi all, I am having the same issue as the ones previously written. I tried the hotfix but it didn't work for me, I am still having a black screen on my phone while I try to build the AR application.
I have the following warnings:

[nory233]

I have the same warnings any help please?

[gteodoro1]

Did anyone manage to fix it? when i run the application it immediatly closes when i grant acces to camera, i don't know if those warnings are the reason.

[tdmowrer]

Did anyone manage to fix it? when i run the application it immediatly closes when i grant acces to camera, i don't know if those warnings are the reason.

That's probably unrelated. App closing unexpectedly could be a crash. Have you checked logcat?

[gteodoro1]

I am using samsung dex, and i can't find any option to check the logcat, i tried some applications on the phone but they don't show the needed information, any recommendation would help.
I checked the logcat, this is the log :

Managed to fix it with the following :Build Settings > Player Settings
Scripting set to IL2CPP
Target Architecture check ARM64

[tdmowrer]

Managed to fix it with the following :Build Settings > Player Settings
Scripting set to IL2CPP
Target Architecture check ARM64

ARCore does not officially support 32 bit on 64 bit devices, and a crash is expected in this case. From https://developers.google.com/ar/64bit:

32-bit-only ARCore-enabled apps that aren't updated will fail to create an ARCore session and might crash when attempting to start an augmented reality (AR) session on affected 64-bit devices.