Unreal Engine 5.7 Preview

John_Alcatraz · September 27, 2025, 10:01pm

There is a regression with VR rendering in the 5.7 preview: Deferred rendering seems to be broken in VR somehow.

Very simple repro steps:

Create a new VR template project
Disable “Forward Shading” in the project settings
Disable “Instanced Stereo” in the project settings
Launch VR preview, move your head left/right and observe significant differences in visuals between the left and right eye. On the right eye everything looks a lot more aliased during movement than in the left eye.

This issue partically also exists with “Instanced Stereo” enabled, but it seems to be a bit easier to reproduce with “Instanced Stereo” disabled. And this is unrelated from any AA, you even see it with AA completely turned off.

Unrelated to the issue above, a different regression with VR rendering that was introduced with 5.6 is unfortunately also still in the 5.7 Preview and not fixed yet:

Create a VR template project
Launch VR preview and enable “r.HZBOcclusion 1”
Move your hand in front of the left eye and see objects incorrectly become invisible on the right eye (the right eye incorrectly uses HZB occlusion info from the left eye). If you test the same in 5.5 or even all the way back to 4.27, you won’t see an issue. 5.6 broke HZB occlusion in VR.

And this issue actually affects multiple different rendering features since many rendering features in the engine rely on HZB occlusion info, even with r.HZBOcclusion set to 0. For example using an Instanced Static Mesh Component with per-instance GPU LOD selection enabled and r.InstanceCulling.OcclusionCull 1 shows the same issue with instances becoming invisible on the right eye if they are occluded by something on the left eye, because that culling is based on the HZB info. Another engine feature that’s broken by this bug is lightgrid culling, which also is based on the HZB info.

Vexar · September 28, 2025, 5:51am

Anyone have a way to restore the UI back to 5.5.4 style? All this extra crap is wasting space.

Jinkel · September 28, 2025, 1:02pm

Window/Layouts

yoyomadafaka · September 28, 2025, 7:34pm

I just tested new vegetable plugin, few trees and 20fps puff go away, I lost hope this engine will usefull

unit23 · September 28, 2025, 7:51pm

What do you get when looking at the shader complexity?

Ideal is a fully greenish view..

S_Mechanic · September 29, 2025, 12:40am

Will 5.6.1 get updated to 5.6.2? The metahuman editor is so buggy

EdHall · September 29, 2025, 4:09pm

WHAT HAPPENED TO FAB?! Is it no longer in Engine? We now have to do the download from Launcher?! I really hope i’m just missing something here, because I don’t see fab plugin available or the Get Content under window for bridge or fab. If we have to exit the project to do all the new downloading and exporting formats instead of simply adding it to our project, that is the dumbest most NOT USER FRIENDLY decision I have seen. What in the world? It was working great and fast inside the editor. Please put back!

Dariusz1989 · September 29, 2025, 6:41pm

Hello

Are the foliage generated trees not supported by path tracer?

Left GPU, Right Path tracer, any ideas?

RotemShi · September 29, 2025, 7:08pm

I’ve given up on VR in UE5. Sticking with 4.27. They just don’t care about VR at all anymore.

controldirective · September 29, 2025, 7:24pm

Pathtracer/raytracing always uses Nanite fallback meshes by default, which in case of the trees looks like this.
You could use r.raytracing.nanite.mode=1 to instead use the full Nanite meshes, just be prepared for a reduction in performance and maybe hitting some buffer limits.
Alternatively you could set the fallback meshes on all the pertaining meshes to 100% (meaning 0% reduction) of the Nanite mesh.

Dariusz1989 · September 30, 2025, 6:41am

Hey

Thanks! Yeah I was getting that result too slowly now. If I set the fallback to 100%, will the GPU/LIT mode still properly do nanite or am I forcing now 100% geometry on all Path Tracer and GPU modes?

Thanks!!!

controldirective · September 30, 2025, 10:34am

I’d rather set r.raytracing.nanite.mode=1 for the pathtracer when you need it, and keep it at 0 if you don’t.
You still want the regular fallback mesh representations if you’re actually doing realtime applications.

Miguel1900 · September 30, 2025, 11:18am

FATAL ERROR when trying to open a 5.6 but very simple project. Even after deleting the Config folder and just keeping the Content:

Fatal error: [File:D:\build++UE5\Sync\Engine\Source\Runtime\RenderCore\Private\ShaderCore.cpp] [Line: 2823]
Couldn’t find source file of virtual shader path ‘/Engine/Private/RayTracing/RayTracingPrimaryRays.usf’

0x00007ffc59cac7c0 UnrealEditor-RenderCore.dll!UnknownFunction
0x00007ffc59cc7dea UnrealEditor-RenderCore.dll!UnknownFunction
0x00007ff605d90752 UnrealEditor.exe!UnknownFunction
0x00007ff605d80a35 UnrealEditor.exe!UnknownFunction
0x00007ff605d80d4a UnrealEditor.exe!UnknownFunction
0x00007ff605d845d0 UnrealEditor.exe!UnknownFunction
0x00007ff605d95c04 UnrealEditor.exe!UnknownFunction
0x00007ff605d98fba UnrealEditor.exe!UnknownFunction
0x00007ffddbf0259d KERNEL32.DLL!UnknownFunction

Miguel1900 · September 30, 2025, 1:08pm

And the ML Deformer seems to be still broken since 5.6, or at least the Sample Project is not ready to use:

TheRealBiomes · September 30, 2025, 3:00pm

Seconding this.

A large number of instanced skinned meshes cause PIE performance to drop heavily.

This makes big or dense forests not usable currently.

Joshuab_artist · September 30, 2025, 3:13pm

hey, I have a question. Does anybody know when will the full release of 5.7 is coming?. I’m just curious about it

Miguel1900 · September 30, 2025, 7:01pm

Mid-end October.

Joshuab_artist · September 30, 2025, 7:26pm

Oh okay, good. I think I can maybe patient for that. At least that’s a better month release than to November which is good. Thanks for letting me know bud

ben-mkiv · October 1, 2025, 5:24am

I hope this gets a little more testing on Linux, because right now it feels unstable (same for 5.6).

It would be great if this gets as stable as 5.5 was/is. Since Megalights scenes look way more consistent now and there have been a lot of good improvements.

SW Raytracing seems to lead to crashes for some users (HW Raytracing seems to avoid that crash) (In my case i have Megalights enabled, not sure if it’s related)
I don’t get this in every level, same for some other user from UnrealSource:

I’ve been having this issue on new project based on fpp template when opening in editor. No issues on empty project.

[2025.09.29-14.34.41:039][737]LogVulkanRHI: Error: VulkanRHI::vkQueueSubmit(Queue, InSubmitInfos.Num(), InSubmitInfos.GetData(), FenceHandle) failed, VkResult=-4
 at ./Runtime/VulkanRHI/Private/VulkanQueue.cpp:491 
 with error VK_ERROR_DEVICE_LOST
[2025.09.29-14.34.41:049][737]LogVulkanRHI: Error: Shader diagnostic messages and asserts:

    Device: 0, Queue Graphics:
        No shader diagnostics found for this queue.

[2025.09.29-14.34.41:049][737]LogVulkanRHI: Error: 
DEVICE FAULT REPORT:
* Description: 
* Address Info: 
    - VK_DEVICE_FAULT_ADDRESS_TYPE_INSTRUCTION_POINTER_FAULT_EXT : 0x000000DEFFD98560 (range:0x000000DEFFD98560-0x000000DEFFD9856F)
    - VK_DEVICE_FAULT_ADDRESS_TYPE_READ_INVALID_EXT : 0x0000000100005000 (range:0x0000000100005000-0x0000000100005FFF)
* Vendor Info: 
* Vendor Binary Size: 0

[2025.09.29-14.34.41:050][737]LogRHI: Error: Active GPU breadcrumbs:

    Device 0, Pipeline Graphics: (In: 0x802ba835, Out: 0x802ba917)
        (ID: 0x802ba82a) [     Active]    Frame 51736
        (ID: 0x802ba831) [     Active]        SceneRender - ViewFamilies
        (ID: 0x802ba916) [     Active]            RenderGraphExecute - /ViewFamilies
        (ID: 0x802ba917) [     Active]                FRDGBuilder::SubmitBufferUploads
        (ID: 0x802ba833) [     Active]                UpdateAllPrimitiveSceneInfos
        (ID: 0x802ba835) [     Active]                    Shadow.Virtual.ProcessInvalidations
        (ID: 0x802ba836) [Not Started]                    GPUSceneUpdate

and some random crashes in Vulkan which look like this (could be related to thumbnail rendering or something, since it happened early on when switching between content browser / viewport)

Signal 11 caught.
Malloc Size=262146 LargeMemoryPoolOffset=262162 
CommonUnixCrashHandler: Signal=11
[2025.09.30-05.13.51:067][199]LogCore: === Critical error: ===
Unhandled Exception: SIGSEGV: invalid attempt to write memory at address 0x00007fdb303d71df

[2025.09.30-05.13.51:067][199]LogCore: 0x00007fdca823ca9f libUnrealEditor-Core.so!mi_heap_malloc_zero_aligned_at [/mnt/evo/UnrealEngine/5.7/Engine/Source/ThirdParty/mimalloc/2.0.0/include/mimalloc-internal.h:561]
0x00007fdca7a91d6e libUnrealEditor-Core.so!FMallocMimalloc::Malloc(unsigned long, unsigned int) [/mnt/evo/UnrealEngine/5.7/Engine/Source/./Runtime/Core/Private/HAL/MallocMimalloc.cpp:73]
0x0000000000236f76 UnrealEditor-Linux-DebugGame!operator new(unsigned long) [/mnt/evo/UnrealEngine/5.7/Engine/Source/Runtime/Core/Public/HAL/FMemory.inl:36]
0x00007fdc8d146d13 libUnrealEditor-Renderer.so!UE::Tasks::Private::FTaskHandle FRDGBuilder::AddSetupTask<FScene::Update(FRDGBuilder&, FScene::FUpdateParameters const&)::$_15, TArray<UE::Tasks::Private::FTaskHandle, TSizedDefaultAllocator<32> > >(FScene::Update(FRDGBuilder&, FScene::FUpdateParameters const&)::$_15&&, UE::Tasks::FPipe*, TArray<UE::Tasks::Private::FTaskHandle, TSizedDefaultAllocator<32> >&&, LowLevelTasks::ETaskPriority, bool, ERDGSetupTaskWaitPoint)::'lambda'()::operator()() [/mnt/evo/UnrealEngine/5.7/Engine/Source/./Runtime/Renderer/Private/RendererScene.cpp:6508]
0x00007fdc8d146fb3 libUnrealEditor-Renderer.so!UE::Tasks::Private::TExecutableTaskBase<UE::Tasks::Private::FTaskHandle FRDGBuilder::AddSetupTask<FScene::Update(FRDGBuilder&, FScene::FUpdateParameters const&)::$_15, TArray<UE::Tasks::Private::FTaskHandle, TSizedDefaultAllocator<32> > >(FScene::Update(FRDGBuilder&, FScene::FUpdateParameters const&)::$_15&&, UE::Tasks::FPipe*, TArray<UE::Tasks::Private::FTaskHandle, TSizedDefaultAllocator<32> >&&, LowLevelTasks::ETaskPriority, bool, ERDGSetupTaskWaitPoint)::'lambda'(), void, void>::ExecuteTask() [/mnt/evo/UnrealEngine/5.7/Engine/Source/Runtime/Core/Public/Templates/Invoke.h:47]
0x00007fdc8c32cef7 libUnrealEditor-Renderer.so!UE::Tasks::Private::FTaskBase::TryExecuteTask() [/mnt/evo/UnrealEngine/5.7/Engine/Source/Runtime/Core/Public/Tasks/TaskPrivate.h:518]
0x00007fdc8c33a876 libUnrealEditor-Renderer.so!LowLevelTasks::TTaskDelegate<LowLevelTasks::FTask* (bool), 48u>::TTaskDelegateImpl<void LowLevelTasks::FTask::Init<UE::Tasks::Private::FTaskBase::Init(char16_t const*, LowLevelTasks::ETaskPriority, UE::Tasks::EExtendedTaskPriority, UE::Tasks::ETaskFlags)::'lambda'()>(char16_t const*, LowLevelTasks::ETaskPriority, UE::Tasks::Private::FTaskBase::Init(char16_t const*, LowLevelTasks::ETaskPriority, UE::Tasks::EExtendedTaskPriority, UE::Tasks::ETaskFlags)::'lambda'()&&, LowLevelTasks::ETaskFlags)::'lambda'(bool), false>::CallAndMove(LowLevelTasks::TTaskDelegate<LowLevelTasks::FTask* (bool), 48u>&, void*, unsigned int, bool) [/mnt/evo/UnrealEngine/5.7/Engine/Source/Runtime/Core/Public/Tasks/TaskPrivate.h:180]
0x00007fdca7820816 libUnrealEditor-Core.so!LowLevelTasks::FTask::ExecuteTask() [/mnt/evo/UnrealEngine/5.7/Engine/Source/Runtime/Core/Public/Async/Fundamental/TaskDelegate.h:309]
0x00007fdca7816140 libUnrealEditor-Core.so!LowLevelTasks::FScheduler::ExecuteTask(LowLevelTasks::FTask*) [/mnt/evo/UnrealEngine/5.7/Engine/Source/./Runtime/Core/Private/Async/Fundamental/Scheduler.cpp:397]
0x00007fdca77d974b libUnrealEditor-Core.so!LowLevelTasks::FScheduler::WorkerLoop(LowLevelTasks::Private::FWaitEvent*, LowLevelTasks::Private::TLocalQueueRegistry<1024u, 1024u>::TLocalQueue*, unsigned int, bool) [/mnt/evo/UnrealEngine/5.7/Engine/Source/./Runtime/Core/Private/Async/Fundamental/Scheduler.cpp:698]
0x00007fdca77da18b libUnrealEditor-Core.so!LowLevelTasks::FScheduler::WorkerMain(LowLevelTasks::Private::FWaitEvent*, LowLevelTasks::Private::TLocalQueueRegistry<1024u, 1024u>::TLocalQueue*, unsigned int, bool) [/mnt/evo/UnrealEngine/5.7/Engine/Source/./Runtime/Core/Private/Async/Fundamental/Scheduler.cpp:816]
0x00007fdca7ad77ef libUnrealEditor-Core.so!FThreadImpl::Run() [/mnt/evo/UnrealEngine/5.7/Engine/Source/Runtime/Core/Public/Templates/Function.h:414]
0x00007fdca7a94386 libUnrealEditor-Core.so!FRunnableThreadPThread::Run() [/mnt/evo/UnrealEngine/5.7/Engine/Source/./Runtime/Core/Private/HAL/PThreadRunnableThread.cpp:25]
0x00007fdca79f7948 libUnrealEditor-Core.so!FRunnableThreadPThread::_ThreadProc(void*) [/mnt/evo/UnrealEngine/5.7/Engine/Source/Runtime/Core/Private/HAL/PThreadRunnableThread.h:187]
0x00007fdc9b4aa4d1 libc.so.6!UnknownFunction(0x8a4d0)
0x00007fdc9b527e38 libc.so.6!UnknownFunction(0x107e37)

[2025.09.30-05.13.51:079][199]LogExit: Executing StaticShutdownAfterError
Additional Crash Context (Key="Breadcrumbs_Parallel_0", Value="Breadcrumbs 'Parallel'
 - SceneRender - ViewFamilies
 - Frame 35199
")[2025.09.30-05.13.51:137][199]LogRHI: Error: Breadcrumbs 'Parallel'
 - SceneRender - ViewFamilies
 - Frame 35199

Malloc Size=1048576 LargeMemoryPoolOffset=1310768

all my stacktraces are on NVidia driver 580.82.09, running X and NOT Wayland.

Random crash from CEF while working on a level (not doing anything involving CEF):

CommonUnixCrashHandler: Signal=4
[2025.10.01-05.12.29:375][375]LogCore: === Critical error: ===Unhandled Exception: SIGILL: illegal instruction
[2025.10.01-05.12.29:375][375]LogCore: 0x00007f2aa3c11225 libcef.so!UnknownFunction(0x6c11225)

edit 9th Oct:
update after using 5.7 for a few days now (rebuilding with current git state each day)

1st quoted crash regarding SW-Raytracing: Haven’t tested sw raytracing again, but with HW raytracing it didn’t happen once. So this seems very likely tied to the SW-Raytracing path

2nd quoted crash: these parallel render crashes still happen A LOT, most often by loading a WorldPartition area with a lot of Assets in them.

~~3rd quoted CEF crash: didn’t happen again as of now, so might be hard to reproduce (or was fixed with a dependency update…)~~
3rd quoted CEF crash just happens randomly, even when doing nothing in the editor and working in another app while UE is in the background.