Resolve the issue of significant lag after VR preview

MioSleet
Tue, 29 Apr 2025 09:56:34 +0000
Blueprint

(Translated by DeepSeek)
Hello, everyone!

I’m extremely excited to share with you how I solved the problem of extreme lag after VR preview.

My hardware configuration is i9-13900KF + RTX 4080 + HTC Vive Pro 2 headset.

This issue seems to occur because, after the VR renders an image, for some reasons, when exiting the preview, the last rendered frame is used as the texture map for a material in the scene.

The resolution of this material is quite high. On my computer, the default monocular resolution exceeds 4000×4000. Although rendering such a texture map doesn’t usually cause lag, but it DOES lag after VR preview

The cause of this problem is rather peculiar and worthy of further investigation.

So, how can we tackle the problem of the excessively high resolution? And where can we adjust the rendering resolution?
You can find the setting in SteamVR → Three horizontal lines → Settings → Video → Monocular Resolution.
Adjust this value to the lowest. It seems that this setting doesn’t affect the clarity during development.

Then, close the UE Editor and restart it. Open the VR preview.
You’ll be amazed to find that the stuttering has disappeared!

This solution seems to reduce the resolution of the last frame from the previous preview rendered in the scene. This significantly reduces the video memory usage, making the editing process in the UE Editor run smoothly again.

(Chinese Origin Text)
大家好！
我非常激动地向各位介绍我如何解决了VR预览后的极端卡顿的问题。
我的硬件是13900KF+RTX4080+Vive Pro 2.
这个问题看上去是因为VR渲染出画面之后，因为某些原因，在退出预览后，会导致最后渲染出的帧作为场景中的一个材质的贴图使用。
这个材质分辨率相当大，在我的电脑中单眼分辨率默认为超过4000*4000。虽然正常情况下渲染这样一个贴图不会卡顿，但是在VR场景中出现了这个问题。
这个问题的原因有点奇怪，这个值得后续研究。

那么，如何解决这个分辨率过大的问题？这个渲染分辨率在哪里调整？
在SteamVR->三条横线->设置->视频->单眼分辨率
调整这个的值到最低，似乎这个值并不影响开发时的清晰度。
然后，关闭UE Editor并重新启动，打开VR预览。
然后你就能惊讶的发现卡顿没有了！
这个解决办法似乎可以将场景中渲染的上次预览的最后一帧的画面分辨率也降低，这极大程度降低了显存的占用，使得UE Editor的编辑流畅度变得正常了

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