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3D widget cause framerate keep dropping in VR 4.19.2

System Environment:Win10 Hardware:CPU:i7-8700, 16GRAM, GTX1070, HTC VIVE/HTC VIVE Pro Engine Version:Version 4.19.2 Binary Step to reproduce:

1.Creat a VRTemplate via 4.19.2 Binary

2.Creat a new 3D widget called UI_Test. There is a Text and an image on the widget.

3.Open the MotionControllerPawn, create a widget component as the child of the Camera component. The widget component’s widget class is set as UI_Test and duplicate the component eight times. So when you play the widgets are always in front of the camera..

4.Run it in VR mode. Open the Fraps and execute the Stat FPS so that we can read the framerate

5.After waiting about two hours(headset not moving at all) the framerate will jump to 78 about 10~30sec a time. (From 90 to 79 and very quickly back to 90, should use the Fraps, because the framerate change too fast, we can’t see the change clearly by command stat fps) And you can feel it if you are wearing the headset.

6.We use the profiler to catch the data on the issue is working, and get a analysis. We found the value of GameThread is very high on each framerate jump down.

7.We keep it running for 12 hours. After that the framerate drop down to 50FPS. Very badly. You can see the steamVR controller bump out inside the HMD with the framerate changing.

8.Open the project, remove the 3D widget component.

9.Restart the UE4 and project, doing the same thing as above step. After 12 hours, the framerate didn’t change at all. It keep 90FPS.

10.We’ve tried this on 4.15.3 and 4.18.3. The framerate is very stable. Only 4.19.2 have this problem.

Summary: We‘ve put the 3D widget in the map and the result is the same. This issue still last even if you travel to another map. Unless you close the entire game.


  1. This issue can be reproduced in 4.20 preview.

  2. This issue can be reproduced on another computer (i7-8700k GTX1080 HTCVivePro)

  3. The picture in the widget is from the engine content.

  4. The framerate will drop faster if you are using multiple 3D widget. Please help us solve this issue since our game is using a lot of plugins which only supports 4.19.2.

  5. The project and the profiler stat as 3DWidgetBug.zip.

  6. Project and profiler data link: https://drive.google.com/open?id=1eRoWqzWFeXoVSQYIOISgeWnXmHB7mm_5 link text

Product Version: UE 4.19
3dwidgetbug.zip (1.9 MB)
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asked Jul 24 '18 at 12:49 PM in Bug Reports

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avatar image Jeff A ♦♦ STAFF Jul 25 '18 at 09:17 PM


We've recently made a switch to a new bug reporting method using a more structured form. Please visit the link below for more details and report the issue using the new Bug Submission Form. Feel free to continue to use this thread for community discussion around the issue.



avatar image jacky_chen Jul 26 '18 at 08:16 AM

OK thanks!

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answered Aug 06 '18 at 02:50 AM

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