[4.8p2] Crash on Building Lightmass

Hi,

I’m running into an issue building the lighting for my level in 4.8 where it used to work perfectly in 4.7. I’m using the latest source release of 4.8 preview 2. I’ve attached the complete log but here is the relevant stack right at the end before it crashes:

[2015.05.14-23.36.45:905][981]LogMaterial: Missing cached shader map for material FLightmassMaterialRenderer MaterialInstanceDynamic_82, compiling. 
[2015.05.14-23.36.45:920][982]LogMaterial: Missing cached shader map for material FLightmassMaterialRenderer MaterialInstanceDynamic_83, compiling. 
[2015.05.14-23.36.45:923][982]LogMaterial: Missing cached shader map for material FLightmassMaterialRenderer MaterialInstanceDynamic_84, compiling. 
[2015.05.14-23.36.45:925][982]LogMaterial: Missing cached shader map for material FLightmassMaterialRenderer MaterialInstanceDynamic_85, compiling. 
[2015.05.14-23.36.48:033][ 25]=== Lightmass crashed: ===
Assertion failed: CurrentMaterialElement.Material [File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.8\Engine\Source\Programs\UnrealLightmass\Private\Lighting\LightingMesh.cpp] [Line: 127] 
Failed to import material with GUID E4309DF94AEEDFB691EEA68C59C351D0


KERNELBASE.dll {0x00007ffcf3eb8b9c} + 0 bytes
UnrealLightmass-Core.dll {0x00007ffca5ebd66f} + 0 bytes
UnrealLightmass-Core.dll {0x00007ffca5d9ff88} + 0 bytes
UnrealLightmass-Core.dll {0x00007ffca5d81708} + 0 bytes
UnrealLightmass.exe {0x00007ff67e0a7cd6} + 0 bytes
UnrealLightmass.exe {0x00007ff67e11257a} + 0 bytes
UnrealLightmass.exe {0x00007ff67e040d03} + 0 bytes
UnrealLightmass.exe {0x00007ff67e0a6552} + 0 bytes
UnrealLightmass.exe {0x00007ff67e0a8270} + 0 bytes
UnrealLightmass.exe {0x00007ff67e07293f} + 0 bytes
UnrealLightmass.exe {0x00007ff67e0af358} + 0 bytes
UnrealLightmass.exe {0x00007ff67e0cd8ef} + 0 bytes
UnrealLightmass.exe {0x00007ff67e12949b} + 0 bytes
KERNEL32.DLL {0x00007ffcf42613d2} + 0 bytes
ntdll.dll {0x00007ffcf6bf5444} + 0 bytes
ntdll.dll {0x00007ffcf6bf5444} + 0 bytes

[2015.05.14-23.36.48:033][ 25]*** CRITICAL ERROR! Machine: machinename
[2015.05.14-23.36.48:033][ 25]*** CRITICAL ERROR! Logfile: UnrealLight_machinename_46CF90494B0EF17CE31AC78C1145C38B.log
[2015.05.14-23.36.48:033][ 25]*** CRITICAL ERROR! Crash report: 
[2015.05.14-23.36.48:033][ 25]LightingResults:Error: Error <None> === Lightmass crashed: ===
Assertion failed: CurrentMaterialElement.Material [File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.8\Engine\Source\Programs\UnrealLightmass\Private\Lighting\LightingMesh.cpp] [Line: 127] 
Failed to import material with GUID E4309DF94AEEDFB691EEA68C59C351D0


KERNELBASE.dll {0x00007ffcf3eb8b9c} + 0 bytes
UnrealLightmass-Core.dll {0x00007ffca5ebd66f} + 0 bytes
UnrealLightmass-Core.dll {0x00007ffca5d9ff88} + 0 bytes
UnrealLightmass-Core.dll {0x00007ffca5d81708} + 0 bytes
UnrealLightmass.exe {0x00007ff67e0a7cd6} + 0 bytes
UnrealLightmass.exe {0x00007ff67e11257a} + 0 bytes
UnrealLightmass.exe {0x00007ff67e040d03} + 0 bytes
UnrealLightmass.exe {0x00007ff67e0a6552} + 0 bytes
UnrealLightmass.exe {0x00007ff67e0a8270} + 0 bytes
UnrealLightmass.exe {0x00007ff67e07293f} + 0 bytes
UnrealLightmass.exe {0x00007ff67e0af358} + 0 bytes
UnrealLightmass.exe {0x00007ff67e0cd8ef} + 0 bytes
UnrealLightmass.exe {0x00007ff67e12949b} + 0 bytes
KERNEL32.DLL {0x00007ffcf42613d2} + 0 bytes
ntdll.dll {0x00007ffcf6bf5444} + 0 bytes
ntdll.dll {0x00007ffcf6bf5444} + 0 bytes

I just tested on a completely brand new “FirstPersonExample” level with starter content enabled and I get the same error.

Latest source build seems to have fixed it. Nothing to see here!