Vive Streaming keeps toggling MR with passthrough off

[Detto_UL]

Hi,

I currently have an issue with using MR/ passthrough with the Vive Hub/Streaming app. I'm currently developing a PCVR app with Unity using Vive OpenXR plugin and an XR Elite. When I toggle the "MR with passthrough" setting on, I can perfectly see the passthrough through SteamVR default room windows.

However, I soon as I launch my app in Unity's play mode, the toggle disables itself, and of course, I can't see the real world in my headset.

I knew it was working before my holidays, and between that, there was the Vive Hub 2.0.0.a update, I suspect it comes from that, but as I didn't find a way to downgrade or see logs, I'm not a 100% sure.

I tried with a new clean project and got the same issue.

So if anyone encountered this problem or has something to add, thanks !

[KyleC]

Hi,

In the lastest version of VIVE Hub, the setting "MR with passthrough" is hardly related to the OpenXR passthrough feature.

I assume you just enabled the OpenXR passthrough feature in VIVE OpenXR plugin but not implemented it yet.

To resolve this situation, I will suggest to refer to the turorial below to implement the OpenXR passthrough feature to control the passthrough start/ stop.

https://developer.vive.com/resources/openxr/unity/tutorials/passthrough/

This is a better to manipulate the passthrough functionality.

 

As to the "MR with passthrough" setting, we target to bundle it to non-OpenXR App in the future. So the OpenXR App won't be affected by this setting.

 

 

 

[Detto_UL]

Hi Kyle,

thanks for the clarification !

When I first added the passthrough, the API given in your link gave me errors (I don't remember what exactly, sorry), but seems to work now.

So, seems the method I used was from a different system and is now obsolete.

I just have a follow-up question about the CompositionLayerPassthroughAPI.CreatePlanarPassthrough(LayerType.Underlay); call in the tutorial, which actually starts the passthrough.

When I don't call it in the start at the beginning of the application, in my case, when I load the passthrough scene, the application continues as normal in the editor/on the PC, but in the headset, it's still stuck in the Streaming Hub Loading App "XXX" part indefinitly.

Is there a recommended time to start the passthrough ? It's not blocking, but it's a little ugly to start the passthrough in the back when it's not currently needed.

[Detto_UL]

I can also add that I have the same issue in the Passthrough_Planar scene the samples from Vive OpenXR plugin. As soon as I create the passthrough, the application freezes in the headset and goes to loading app mode, and when I destroy it, it goes back to normal.

 

[KyleC]

Hi Detto_UL,

We have tested again with our latest VIVE OpenXR plugin (2.4.1) and VIVE Hub Beta (2.0.0a), and the sample in VIVE OpenXR plugin work normally. (The example shows a cube and some instructions to press controller button to enable/disable the passthrough)

Could you help to check your environment again to see if the SW are all up-to-date:

- VIVE Hub: Beta 2.0.0a

- VIVE Streaming client: Setting -> About -> VIVE Streaming

- VIVE OpenXR plugin: 2.4.1

 

And register the VIVE OpenXR again in Settings->Advanced to the bottom.

[Detto_UL]

VIVE Hub is 2.0.0.a, Vive Streaming PC is 1.15.11c and Vive Streaming Headset is 1.0.21.14e, VIVE OpenXR Plugin is 2.4.1.

Here's a record of the issue in case it's a bit clearer for you. I've record the headset screen using Vive's recorder.

You can see that the app is fine, but I soon as I press the right trigger, the app is freezed, with the "Waiting for..." panel and I'm back in the default environnement. The passthrough we see is probably just the usual out-of-playspace passthrough (notice that the sample scene controllers are not moving).

When I press the left trigger to destroy the passthrough, everything goes back to normal.

Don't hesitate if you need logs or something else.

[KyleC]

Hi Detto_UL,

Thanks for the detailed information. It seems that your passthrough is working well, but the performance wasn't that good while enabling it.

May I know what is your GPU/ CPU? We guess because it consumes a lot of PC resource while enabling passthrough, so the loading at that moment is high which causes SteamVR stop rendering.

I'll suggest you could try to change the streaming graphic mode to Performance. (Settings->VIVE Streaming->Graphics->Streaming graphics preferences)

And it would be helpful if you can provide the log as well. (Settings->About->Report issue)

 

[Detto_UL]

Hi Kyle,

As I said in a previous post, starting the passthrough immediately at the start of the app works fine without any performance issue. I tested it again in the sample scene by slightly modifying the code.

As I have an Intel i7-14700 CPU and a RTX 4070 GPU as well, it's a 100% NOT a performance issue. I also tested with USB and Wi-Fi connection to Vive Streaming in case in was a transmission issue, but no difference either.

The logs are a bit heavy to submit on the forum, but I sended the report, with trace number 20240905082726.