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"

PhysX Crash During Destructible Mesh Creation

Hey guys,

Currently working on a project that involves building a lot of structures from hierarchical instanced static mesh components. We want these buildings to be destructible, so I've attached a component to the player character that, on tick, does an OverlapMultiByObjectType, gathers all the HISMCs in a radius around them, and replaces them with destructible mesh components.

After a certain number of conversions, the engine crashes. The number of conversions required varies based on settings (see below callstack for details).

The engine is crashing with this callstack:

 Access violation - code c0000005 (first/second chance not available)
 UE4Editor_Engine!TGraphTask<FPhysXTask>::ExecuteTask() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\core\public\async\taskgraphinterfaces.h:779]
 UE4Editor_Core!FTaskThread::ProcessTasks() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\core\private\async\taskgraph.cpp:539]
 UE4Editor_Core!FTaskThread::ProcessTasksUntilQuit() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\core\private\async\taskgraph.cpp:340]
 UE4Editor_Core!FTaskThread::Run() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\core\private\async\taskgraph.cpp:690]
 UE4Editor_Core!FRunnableThreadWin::Run() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\core\private\windows\windowsrunnablethread.cpp:74]

I'm having serious trouble tracking this one down, and it's getting very frustrating. I have discovered two things:

1) Disabling "Form Extended Structures" on the destructible mesh significantly reduces the frequency of crashes (with it enabled, it crashes within the first 5-10 HISMC conversions. With it disabled, it can take from 13000 - 20000 conversions to do it). Note that having "Form Extended Structures" enabled also significantly reduces the project's performance/FPS, so perhaps physics processing time has a connection.

2) Enabling the async scene slightly reduces crash frequency (instead of 5-10 conversions, about 150 - 200).

3) Commenting out the destructible mesh spawning code, but leaving the HISMC removal code in, causes the crash to stop occuring. The other way around, however, does not. So it's connected to the destructible mesh spawning, not the HISMC removal.

I could really use some help on this. I can't have a crash like this lingering around in my project, and it's starting to feel impossible to debug on my own. Spent about 8-10 hours on it so far, fiddling with everything I could think of.

Thanks in advance!

Product Version: UE 4.10
more ▼

asked Jan 29 '16 at 11:01 PM in Bug Reports

avatar image

6 1 4 6

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

1 answer: sort voted first

Hi Beowulfe,

Thanks for the details! This is a known crash that we have reported as UE-22078. It appears to be a PhysX crash when spawning Instanced Static Meshes at runtime. A fix has been created in our internal dev branches but it's not ready to integrate into the main branch quite yet. The developers are still hoping to get it fixed for 4.11. I'll update the post with your notes and let you know if I see any update on it. Thanks again!

more ▼

answered Jan 31 '16 at 05:39 PM

avatar image Beowulfe Feb 01 '16 at 03:48 PM

Great, thanks, keep me updated. Really hoping this makes it into 4.11, as it's a key component to our project.

Just to double check one thing - You mentioned it was a crash caused by spawning ISMs at runtime. As far as I can tell, with my crash, I can spawn and remove any number of ISMs without any issues. It's when I start spawning destructible mesh components in their place that the issue occurs.

I can see that still being related, but I wanted to double check there wasn't a second underlying issue at play.

avatar image Ben Halliday STAFF Feb 01 '16 at 04:31 PM

The devs believe it's a crash in destruction, something about a null entry in a deleted pair that isn't supposed to be null, so it may have more to do with replacing the ISMs with Destructible Meshes than simply spawning ISMs or Destructibles. Regardless, it's going to be difficult to be sure until this fix is integrated. If you're building from source, I can find the GitHub commit once it's released so you can try it, otherwise I'll figure out which Preview build it would make it to and let you know.

avatar image Beowulfe Feb 01 '16 at 04:50 PM

I'm not currently building from source, but I do have the GitHub engine files downloaded, so I can give it a shot once the commit goes live. If you get a chance to pass me the commit info once it up, that'd be great. I'll keep my eye on the 4.11 preview changes as well. Thanks. :)

avatar image RayJohannessen Apr 01 '16 at 08:31 PM

Hey, curious if this has this been resolved in the 4.11 patch...

avatar image Sean L ♦♦ STAFF Apr 06 '16 at 06:50 PM


This issue has been reported fixed in 4.11. If you are still seeing the issue occur in 4.11, please let us know.

Have a great day

avatar image RayJohannessen Apr 07 '16 at 04:48 PM

Awesome, thanks Sean!

(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