Transparent objects render wrong in VR with Stereo Instancing

If you turn on Stereo Instancing in 4.11, and you turn Anti Aliasing OFF or set it to FXAA, all your transparent objects that are instanced by default (Instanced static mesh actors or Hierarchical Instance Static Mesh Actors) are rendered wrong in your left eye.

For example transparent foliage will look wrong.
The translation of the instanced objects seems to be off for your left eye.

Here is a repro case:

  • Start a new Default scene (Not an empty one)
  • Enable Stereo Instanced rendering in the project settings.
  • Add a piece of terrain.
  • Add a piece of foliage that includes transparency.
  • Add a post process volume
  • Set the volume to unbound
  • Disable or set the AA Setting to FXAA (Under Misc)
  • Preview the map in VR

Now you can observe that the left eye doesn’t render the foliage as it should.

We’re also experiencing this issue. Thanks for the clear repro steps Perfect_Storm!

@Epic can you confirm you can repro this on your side as well?

Hello,

What device(s) are you seeing this issue on specifically?

Im experiencing the issue on the oculus headset.
Using the latest 1.3.2 software.

We see this on PC (Windows in this case) with Oculus Rift retail hardware (SDK 1.3) - Unreal Engine version 4.11.2

We see this on PC (Windows in this case) with Oculus Rift retail hardware (SDK 1.3) - Unreal Engine version 4.11.2

It is a real show stopper for us using instanced stereo rendering (hoping for a hotfix!!!)

[EDIT] Apparently this is fixed in CL 2960162. I’m going to integrate that in our engine to verify if it solves our issues.

[UPDATE] It is fixed when we integrated the mentioned changelist.

Hello everyone,

This looks like an known issue (UE-30099). This issue has been fixed internally, and the fix will be released in a later version.

As VanguardGames stated, you can find the fix in CL 2960162 if you’d like to integrate it yourself.

Have a great day