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(OpenXR for Mobile / Unreal 5.1) ClearAlpha stopped working in passthrough


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I have used the example "ClearAlpha" material to mask out things when using passthrough. For example use it for transparent walls to hide everything that is behind it.

I updated my firmware to the latest (1.3.999.352) and now the clearAlpha material "leaks" the object behind the masking object. 

Any ideas what material function should be used to "poke a hole" on scene when in passthrough mode?

- using the latest OpenXR for mobile plugin
- using UE 5.1.1
- Vive XR Elite with 1.3.999.352

"ClearAlpha" material is used on the top most vertical cube in this picture, it was used to be full passthrough, now the face is "ghosting" light.



Edited by vanheinonen
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Hello, I am from the plugin development team, also the one who made the ClearAlpha and ClearColor materials for the Underlay Passthrough feature.

Am I understanding your goal correctly by saying that you are trying to use the passthrough image to occlude virtual objects, by using the materials we provided for "poking a hole"? In that case, using the "ClearAlpha" material alone will not be enough to achieve what you want.

In addition to what you have already done, You will have to duplicate the object and apply the "ClearColor" material to it, as different materials are needed for writing the necessary RGBA values for a complete passthrough.

Hope this helps.

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Dear Aidan Leung, you are a lifesaver!

I feel happy and stupid at the same time, but now it works!

I have implemented a "poke a hole" for Varjo XR3 and Meta Quest Pro headset, all with slightly different ways of doing this in Unreal Engine.

Thanks a lot!


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