Water Plugin Causing Crash In 5.4.4

Development Platform & Builds XR Development
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Please Note! In the uploaded VR Template project (TempAgain.Uproject), there is a secondary level called ‘WaterMap’. If you attempt to load into this level, the crash will occur as there is a water body already placed in the scene from when instanced stereo was disabled and the level was saved with it in.

You do not need to press ‘Play’ in order for this issue to present itself. Simply adding a water body into the scene will cause the crash.

Disabling two settings, ‘Instanced Stereo’ and ‘Forward Shading’ off is the only way to be able to view the water in VR, however having them switched off causes a drop in FPS for the VR platform.

There is a thread in the Unreal Forums which details additional versions of unreal in which the issue can be replicated - https://forums.unrealengine.com/t/water-plugin-crashes-the-engine-5-4-1/1884479/24

The latest update mentions that in 5.6 this method no longer crashes however water is rendered incorrectly when the settings are enabled or not displayed at all in VR when these settings are disabled.

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Steps to Reproduce

  1. Launch Unreal Engine 5.4.4 and create a VR Template. Please note, you don’t need to have starter content ticked.
  2. Once the engine has been loaded into the VR Template map, navigate to Edit->Plugins, in the search bar, type ‘Water’. Enable the water plugin by pressing the tick to the left of it.
    1. Please note, you do not need to enable the ‘Water Extras’ plugin. [Image Removed]
  3. Next, Navigate to Edit->Project Settings. In the search bar type ‘Instanced Stereo’ and tick to enable.[Image Removed]
  4. Once both the plugin and this setting is enabled, restart the editor.
  5. Once loaded back up, navigate to Quick Add button and type ‘Water’ in the search. Select one of the following and place it in the level

  • Water Body Lake

  • Water Body Ocean

  • Water Body River

    6\. As soon as you click to place one of those actors down, the engine will crash.
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Hi there,

Thank you for reaching out and providing detailed reproduction steps for the crash you’re encountering with the Water Body plugin. We’ve reviewed the behavior and wanted to provide both some immediate workarounds and some details on issues present in later versions of the engine, should you choose to upgrade.

To work around the immediate crash in editor, you can set the following console variable in your project’s defaultEngine.ini:

r.Water.WaterInfo.RenderMethod=0

This will set the water info render method back to the legacy rendering method, which still works in 5.4, even with forward shading and instanced stereo enabled.

However, please note that this workaround only addresses the editor crash. Unfortunately, a separate known issue exists with the water body plugin and the default OpenXR backend. This causes a crash when playing using a VR headset in unreal engine 5.4. To address this second crash, you have two options:

Fix Option 1 – Source Engine + Patch

This issue is addressed in the following git commit: 781eb1e8 (Fix crash in water rendering when running with ISR on an OpenXR device (UE-207585))

If you’re using asource version of UE 5.4, or are willing to switch to source, you can cherry-pick the above commit to eliminate the crash.

Fix Option 2 – MetaXR Plugin (No Source Build Required)

As an alternative workaround, that does not require modifying the engine source:

  1. Install and enable the MetaXR plugin from Meta.
  2. Set the MetaXR->XR API to Oculus OVRPlugin + OpenXR backend in project settings (This is the default)

This avoids the OpenXR crash entirely for Meta headsets. However, please note that this approach will only work on Meta devices and is not a general solution for all PCVR platforms.

If you’re planning to upgrade to a later engine version, be aware of the following regressions in water rendering:

UE 5.6+

Water Body tile culling / flicking issue in VR. Water tiles flicker in and out of visibility when rendering with instanced stereo.

Requires instanced stereo rendering to be enabled (does not require forward shading to be enabled)

Must be either playing in VR or running with Emulated Stereo

UE 5.5+

Missing, patchy and incorrectly located water in VR. Water is missing or appears in wrong places due to incorrectly rendered WaterInfoTexture.

Does NOT require forward shading or instanced stereo to be enabled

Occurs only when playing in VR with a real VR headset (tested with Meta Quest 2 via link cable)

Does not occur when using emulated stereo (To test stereo rendering without a headset attached)

Workaround:

With forward shading DISABLED; setting r.Water.WaterInfo.RenderMethod=1 seems to resolve the issue. However, setting this console variable, with forward shading ENABLED, results in a crash.

UE 5.5 - 5.6 (Not present in latest ue5-main branch)

Missing, patchy and incorrectly located water in Editor. Water is missing or appears in wrong places due to incorrectly rendered WaterInfoTexture.

Workaround:

Disable forward shading.

Let us know if you have any further questions. We’ll also be submitting the two water body XR rendering issues affecting ue5-main for internal tracking, since these issues don’t appear to be known yet.

Best regards,

Thomas

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Hi there,

Here are the two bug tracking links for the issues present in ue5-main.

https://issues.unrealengine.com/issue/UE-296373

https://issues.unrealengine.com/issue/UE-296375

Going forward these will provide the most up-to-date information regarding these reports. If you find any additional behaviour or information you would like to report, please feel free to get back in touch.

Thanks again,

Thomas

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HI Thomas, thank you very much for getting back to us, its appreciated. We shall review the above methods you have mentioned and look into which one works for us!

Also, thanks for creating the tracking links, those will be very helpful!

Many Thanks