Search in
Sort by:

Question Status:

Search help

  • Simple searches use one or more words. Separate the words with spaces (cat dog) to search cat,dog or both. Separate the words with plus signs (cat +dog) to search for items that may contain cat but must contain dog.
  • You can further refine your search on the search results page, where you can search by keywords, author, topic. These can be combined with each other. Examples
    • cat dog --matches anything with cat,dog or both
    • cat +dog --searches for cat +dog where dog is a mandatory term
    • cat -dog -- searches for cat excluding any result containing dog
    • [cats] —will restrict your search to results with topic named "cats"
    • [cats] [dogs] —will restrict your search to results with both topics, "cats", and "dogs"

Office Holiday

Epic Games' offices will be on holiday from June 22nd to July 7th. During this period support will be limited. Our offices will reopen on Monday, July 8th. 

Crash because of NaN, dynamic shadows related?

First info, I'm on 4.8.2.

For some reason that I have not been able to accurately pinpoint, I have a crash that happens seemingly at random: it's not always after the same amount of time, not at the same place, not at the same part of the game flow. It's seems to be occuring within the rendering thread and is basically complaining about a NaN matrix.

I would like to have at least a hint of what is going on, as far as I know, I don't see any artifact or glitch in the scene as simply replacing the NaN matrix for the Identity matrix seems to correctly "bypass" the issue. Nevertheless, I would like to understand what is going on, and if you have any idea what can cause this or how to proceed to get a better idea of what is going on, please let me know!

Some of the logs seem to be pointing at an emitter from a particle system, but before recently, I did not have any issue with said particle system. I am currently thinking it could be a mixture of dynamic shadows and some types of emitters that do not play well together...but that's just a guess...

Here is a part of the crash error log, attached is the complete log. Please note that the logs are not always the same, sometimes it gives different but similar output. link text

Thanks in advance for the help!


 LogUnrealMath:Error: FMatrix::InverseFast(), trying to invert a NIL matrix, this results in NaNs! Use Inverse() instead.
 LogOutputDevice: === Handled error: ===
 Ensure condition failed: false [File:c:\users\mdube\perforce\prodperforce\jotunn\engine_4.8_base\engine\source\runtime\core\public\math\UnrealMatrix.h] [Line: 266]
 FMatrix::InverseFast(), trying to invert a NIL matrix, this results in NaNs! Use Inverse() instead.
 UE4Editor-Core.dll!FWindowsPlatformStackWalk::StackWalkAndDump() {0x00007ffab34eb036} + 0 bytes 

Product Version: UE 4.8
errornan.txt (19.1 kB)
more ▼

asked Nov 06 '15 at 03:15 PM in Bug Reports

avatar image

2.1k 70 37 259

avatar image Doug E ♦♦ STAFF Nov 09 '15 at 07:08 PM

Hey Michaël-

There is not really enough information for me to investigate/reproduce the crash on my end. You mentioned that the crash happens after a set amount of time, does that mean that after pressing PIE the crash is guaranteed after a little bit without input? Would it be possible for you to send me a copy of the project where the crash is occurring? You can do so by uploading the project and sending me a link to download it from. If you would rather do this privately you can send me a private message on the forums with the link rather than posting here.


Doug Wilson

avatar image MickD777 Nov 10 '15 at 02:55 PM

It's not really possible for me to get the whole project to you, I'll try to isolate the issue in a single map and send it your way when I have some time. Like I said, the crash is pretty random, I really dont know what could be happening and don't know the specifics of how to reproduce, I was just hoping for some "oh I saw that before it's because of X" but I guess that cannot be that easy :P

Thanks anyway, and i'll update this issue as soon as possible...

(comments are locked)
10|2000 characters needed characters left
Viewable by all users

1 answer: sort voted first

Hey Michaël-

Were you able to find any additional information about the crash? For now I am marking this post as resolved for tracking purposes however you can reopen this by adding a comment. If you do encounter this crash again, please provide the callstack and the log files from the crash for more information.


Doug Wilson

more ▼

answered Nov 16 '15 at 09:26 PM

(comments are locked)
10|2000 characters needed characters left
Viewable by all users
Your answer
toggle preview:

Up to 5 attachments (including images) can be used with a maximum of 5.2 MB each and 5.2 MB total.

Follow this question

Once you sign in you will be able to subscribe for any updates here

Answers to this question