Build in 4.11 crashes the editor instantly every time (maybe HLOD related)

If i click the build button in unreal engine 4.11 it crashes the editor. Instantly… with the whole send a report a bug message and all that… I tried twice so far… both times instant crash. Sucks. Was looking forward to kicking off a light build to try out this new light build stuff you guys mention is twice as fast… but so far no luck. I am using HLOD for this build which i have never attempted before.

“Assertion failed: SubActorMesh->HLODTreeIndex == 0 [File:\BuildFarm\buildmachine_++UE4+Release-4.11\Engine\Source\Editor\UnrealEd\Private\StaticLightingSystem\StaticLightingSystem.cpp] [Line: 779]
ERROR: HLODTreeIndex != 0 for ‘/Game/Maps/BathHouseResort_HLOD/Section_GuestRooms.Section_GuestRooms:PersistentLevel.FogSphere95.StaticMeshComponent0’ while processing LOD actor ‘LODActor_39’”

After a quick test building without HLOD had no problems with building. So HLOD it would seem is the cause of the crashing. I tested by duplicating the directory for all the levels that stream with an exact copy of all of them. One using HLOD the other not. The one not using HLOD built just fine. So why would HLOD cause crashes for a build?

Hello -

I am attempting to reproduce the crash internally, but it would be helpful if you could reproduce the crash and submit via the crash reporter and post your machine ID here.

Thank You

Eric Ketchum

i clicked send and close upon replicating the crash. How do i find my machine id?

The Machine ID, i believe is stored somewhere in the registry. Its easier to reproduce the crash and the Machine ID will appear in the crash reporter window.

Eric

MachineId:D3EBC2484103BE1B45B3F590087F686A
EpicAccountId:25a93c40348648ad81705a463b6d9b35

I’ve tried for a little bit here to see if I can get the crash on my end in 4.11, but I’m not getting the same results.

I setup a basic level with ~1000 actors and generated the HLODs then built lighting without issue. I then used streaming levels to see if that would reproduce the issue, but still no luck.

Looking at the crash call stack it’s possibly linked to the asset FogSphere95. Can you tell me anything about this asset, like it’s relative size and is this just a replacement for the skysphere or are there multiples of these around the level?

Also, when I did this test, I used just a basic HLOD default settings with a single HLOD. Are you using multiple HLOD levels, and if so, what are the settings you’ve setup thus far.

One last test to rule out this asset FogSphere95. If you go into the details panel and uncheck the option for Enable Auto LODGeneration for this asset and build lighting, do you still get the crash?

Thank you!

Hey Tim, Fogsphere is a static mesh with a material for fading in and out… basically its fake volumetric fog around light sources… I think I may have gotten this from infiltrator demo or something like that since i didnt make it myself… There are many of these through out different “maps/sections”.

As for HLOD settings… I left everything on default. I never touched them. I have had problems with HLODs in the past unreal engine versions, but i dont remember what hte problems were. I dont think they were crashes but i could be wrong. I simply left HLODs disabled since i could never make these things work correctly in my experience.

I will try that enable auto lodgeneration setting later when I get home. Though I cannot see how it would just be 1 fogsphere that is the issue… they are literally duplicates of each other and theres like 30 of these things in the scene.

One map does have foliage in there if that matters for anything.

Hey Tim,

So I double checked HLOD levels… yea its all default without multiple.

I also tried to uncheck enable auto LODGeneration for that one fog sphere… did not work.

Still crashes. In fact the crash message still mentions that FogSphere95 even though LOD generation is unchecked.

I tried deleting the fog sphere… and it crashed immediately after hitting build again… it just replaced that mesh in the error message with another random one… “Japan_Temple_gate_a_wall47” is the new one… so nothing to do with the specific mesh it would seem.

Thanks for the notes. I’ll have a look and see if I can get anywhere with that and get back to you.

That does seem odd it’s not specific with the mesh since it directly called it out.

Well, after a good bit of time I was able to finally get the crash in 4.11 P4 with the same call-stack, except it pointing to a different mesh in mine. I only used a default level with ~3300 spheres set. I was even able to reproduce your steps of disabling the HLODs and it would build fine. So I got a “win” there.

I then opened the same project in 4.12 and regenerated the HLODs and built lighting without issue. I tried this several different ways and couldn’t reproduce the crash. It’s possible this has been resolved since there are still a lot of active changes and fixes going into HLODs to make them better.

Thats interesting. So when does 4.12 come out ? lol

It’s not for a few more months. We’re mostly on quarterly releases at this point. I don’t have a specific date that I can make public at the moment though. :confused:

Oh well… i’ve never been able to make HLOD work proper anyway so I wasnt planning on relying on that for optimizing.

Putting the answer here for the moment.

After having tried reproducing this in 4.11 Preview builds I was able to reproduce the crash. Testing this same crash in our internal build of 4.12 the crash appears to no longer be happening. It is likely this has been fixed internally and will be resolved when 4.12 comes out in a few months.

Should this crash still persist after 4.12’s release or during the preview builds, this post can be reopened for investigation.

Yeah, sorry about the inconvenience. I think I had suggested this as a possibility to you at one point. Hopefully with all the testing and development being done for Paragon with it it will be stellar when it’s done. I did see a ticket in the other day to add functionality for LOD support so that it uses the static meshes already set LODs from Simplygon or ones that are manually created.

Yea you did. Thanks for all the help. I’ll give it a try again when we hit 4.12 Oh and the LOD support will be so ■■■■ awesome. Any idea if thats coming in 4.12 or 4.11?

Definitely won’t be 4.11. 4.12 possibly, but I only saw it as a feature request with that as a target release. That can always get pushed out though.