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Light Propagation Volume enabled causes "Assertion failed: IsInRenderingThread()" crash in Development build


Enabling LPV by adding "r.LightPropagationVolume = 1" to either the engine's ConsoleVariables.ini or a project's DefaultEngine.ini causes Development builds to crash when run.

Note: There are 0 error(s) and 0 warning(s) reported when building.

Note: Only Development builds crash. Shipping builds appear to run fine. The game runs fine in editor.


1) Launch 4.17

2) Create a new blank project with no starter content

3) Go to File --> Save Current As and click Save to save the default map as "NewMap" in the Content folder

4) Go to Edit --> Project Settings --> Maps and Modes and set NewMap to be the default Editor Startup Map and Game Default Map

5) Close the window and exit the editor

6) Do one of the following:

Add "r.LightPropagationVolume = 1" to the engine's ConsoleVariables.ini file and save it


Add the following to the project's DefaultEngine.ini file in the project's Config folder and save it


r.LightPropagationVolume = 1

7) Restart the editor and re-open the project

8) Check that File --> Package Project --> Build Configuration is set to Development

9) Package a build by going to File --> Package Project --> Windows --> Windows (64-bit)

10) Select a folder location and click Select Folder

11) The build will complete with 0 errors and 0 warnings

12) Run the build from the selected location in Windows and it will crash with the following error:

The Game has crashed and will close

Assertion Failed: IsInRenderingThread() [File:D:\Build\++UE4+Release-4.17+Compile\Sync\Engine\Source\Runtime\Renderer\Private\PostProcess\SceneRenderTarget.cpp][Line: 2070]

Product Version: UE 4.17
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asked Aug 21 '17 at 07:59 AM in Bug Reports

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avatar image Rudy Q ♦♦ STAFF Aug 23 '17 at 08:01 PM

Hello afelius,

Thank you for the information above, however I was unable to reproduce this issue on our end. Could you provide a sample project so that I could take a closer look?

avatar image Pittnee Aug 24 '17 at 07:24 AM

Sure thing. What is the preferred method? If you send me a PM, I can provide a link to a test case.

Also, FYI, I've reverted my actual project back to 4.16 so this is no longer relevant. I started getting a lot of crashes upon compile and play in editor.

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I was able to reproduce this issue on our end with the information provided. I have written up a report and I have submitted it to the developers for further consideration. I have provided a link to the public tracker. Please feel free to use the link provided for future updates.

Link: https://issues.unrealengine.com/issue/UE-49205

Make it a great day

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answered Sep 01 '17 at 05:30 PM

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Rudy Q ♦♦ STAFF
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