Unreal Engine 4.20 Preview

[NilsonLima]

Getting very strange 13-16ms frame time jumps in PIE or pure game mode (game launched separately) even on fresh empty projects, I have tracked it down to "UI Drawing Time" (this is not Slate/Editor UI) function in the game thread. Any idea how to fix the issue, the root cause of the bug?

it might be related to this: https://forums.unrealengine.com/unre...ups-constantly

[dreamingderp]

The fbx, importer on 4.20 isn't working it just crashes or says unable to load file, just a heads up.

[Jamie Dale]

Hey guys, i'm still a bit new to Unreal and Python... but I have been playing with their native Python. Can anyone help me get the selected asset from the content browser via Python? I thought this one would do the trick, but I get an error:

unreal.GlobalEditorUtilityBase.get_selected_assets()

The error is :
TypeError: descriptor 'get_selected_assets' of 'GlobalEditorUtilityBase' object needs an argument

What type of argument would I need to write to get it to check what I have selected?
Thanks ahead of time, guys

That's an abstract class and is likely designed for Blutilites rather than Python (it looks like you'd need to derive from it as it's a non-static function so it's expecting a "self" argument).

You could try this (untested), which is gross, but I don't know if there's another way to get the Content Browser selection right now.

@unreal.uclass()
class MyEditorUtility(unreal.GlobalEditorUtilityBase):
    pass

editor_util = MyEditorUtility()
editor_util.get_selected_assets()

FWIW, the Python "help" command works for our types and will tell you things like their expecting signature, and you can always expose any functionality that is missing by writing custom UFUNCTIONs for it.

[Chui_Panda]

That's an abstract class and is likely designed for Blutilites rather than Python (it looks like you'd need to derive from it as it's a non-static function so it's expecting a "self" argument).

You could try this (untested), which is gross, but I don't know if there's another way to get the Content Browser selection right now.

@unreal.uclass()
class MyEditorUtility(unreal.GlobalEditorUtilityBase):
pass

editor_util = MyEditorUtility()
editor_util.get_selected_assets()

FWIW, the Python "help" command works for our types and will tell you things like their expecting signature, and you can always expose any functionality that is missing by writing custom UFUNCTIONs for it.

That did indeed do what I needed. Thank you so much! I still have a lot to learn, but glad to be learning every day!

[fpwong]

Getting very strange 13-16ms frame time jumps in PIE or pure game mode (game launched separately) even on fresh empty projects, I have tracked it down to "UI Drawing Time" (this is not Slate/Editor UI) function in the game thread. Any idea how to fix the issue, the root cause of the bug?

Narrowed it down to the same line as you AtsK. I went to build the engine to check exactly what it is using the 4.20 branch and the issue seems to be gone? Fingers crossed everything works fine in the next preview.

Also I have a feeling this is not the same issue as people are having over in the other post below as I have had no issues at all with 4.19, is that the same for you too Atsk?: https://forums.unrealengine.com/unre...ups-constantly

[kgamble]

I'm running into the following error when I try to run a packaged build made with preview 4:

Assertion failed: !GEventDrivenLoaderEnabled [File:D:\Build\++Shared\Sync\Engine\Source\Runtime\Core\Private\Internationalization\TextHistory.cpp] [Line: 1276]

It's possible this also occurred in previous previews but due to a different bug I wasn't actually able to successfully package my project until preview 4. Turning off event driven loading does fix the problem but my understanding is that it improves load times (though I couldn't find anything definite about this so I may be wrong) so I'd like to keep it enabled if possible.

I'd like to make an official bug report for this but I have no idea where to even start working on a repro case so if anyone has any suggestions/guidance I'd love to hear it. Thanks.

[gozu]

Please have as many previews as you need to fix all the bugs! Awesome job so far though!

I Agree! Please fix the nvidia hang bugs!

[mebalzer]

UPDATE!

We have just released Preview 4 for 4.20! Thank you for your continued help in testing the 4.20 build before its official release. As a reminder, the Preview builds are for testing only, and should not be used for the active development of your project.

For a list of known issues affecting this latest preview, please follow the links provided on the first post in this thread.
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Fixed! UE-54455 MR Calibration: When calibrating with Vive, alignment models don't show up

REMEMBER: Please report any new bugs you find by following the How To Report a Bug Guide

I don't know who was able to report this for the Mixed Reality Framework plug-in (I am assuming that is what MR means), but I have not been able to find any of the calibration tools or the calibration map from 4.18. I also noticed many of the function calls have been renamed so you cannot use the 4.18 calibration map either. Regardless, I have been able to stumble through locating the Mixed Reality Camera actor and put together a very unpolished tutorial of setting up a camera in your map and then assign a webcam and adjusting parameters for green screen use. However, I still have figured out why I cannot use my Windows Media compatible Magewell V1 HDMI->USB-3 converter.

https://youtu.be/y6R0FGrAyXU?t=3611

[Jamie Dale]

I'm running into the following error when I try to run a packaged build made with preview 4:

Assertion failed: !GEventDrivenLoaderEnabled [File:D:\Build\++Shared\Sync\Engine\Source\Runtime\Core\Private\Internationalization\TextHistory.cpp] [Line: 1276]

Hey, this is a known issue and the assert has since been removed. It seems that in some cases EDL can become enabled between the Serialize call, and the call that attempts to process the deferred load action.

[HateDread]

• Visual Studio 2017. UE4 will now use the Visual Studio 2017 compiler, and generate project files for Visual Studio 2017 by default. We’ve also added support for the Windows 10 SDK.

Does this mean we can build against C++17? I'm including some third party libraries that use

std:optional

in their interface but building still fails under 4.20 Preview 4.

fatal error C1189: #error:  class template optional is only available with C++17

Any way to make this work? Perhaps passing /std:c++17 to the compiler?

EDIT: So I realized I can probably pass the flag in via the TargetRules' AdditionalCompilerArguments field, but this requires a Unique build environment. When I set the build environment to 'Unique' like so (but make NO other changes);

BuildEnvironment = TargetBuildEnvironment.Unique;

My build fails with;

1>UnrealBuildTool : error : System.IO.DirectoryNotFoundException: Could not find a part of the path 'C:\_Development\Repositories\rtg\UE4\rtg_client\Intermediate\Build\Win64\rtg_clientEditor\Development\Launch\Launch.precompiled'.
1>                           at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
1>                           at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy, Boolean useLongPath, Boolean checkHost)
1>                           at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, FileOptions options, String msgPath, Boolean bFromProxy, Boolean useLongPath, Boolean checkHost)
1>                           at System.IO.StreamReader..ctor(String path, Encoding encoding, Boolean detectEncodingFromByteOrderMarks, Int32 bufferSize, Boolean checkHost)
1>                           at System.IO.File.InternalReadAllText(String path, Encoding encoding, Boolean checkHost)
1>                           at Tools.DotNETCommon.JsonObject.Read(FileReference File) in D:\Build\++Shared\Sync\Saved\CsTools\Engine\Source\Programs\DotNETCommon\DotNETUtilities\JsonObject.cs:line 50
1>                           at UnrealBuildTool.PrecompiledManifest.Read(FileReference Location) in D:\Build\++Shared\Sync\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\System\PrecompiledManifest.cs:line 37
1>                           at UnrealBuildTool.UEBuildModuleCPP.Compile(ReadOnlyTargetRules Target, UEToolChain ToolChain, CppCompileEnvironment BinaryCompileEnvironment, List`1 SharedPCHs, ISourceFileWorkingSet WorkingSet, ActionGraph ActionGraph) in D:\Build\++Shared\Sync\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\Configuration\UEBuildModuleCPP.cs:line 425
1>                           at UnrealBuildTool.UEBuildBinary.SetupBinaryLinkEnvironment(ReadOnlyTargetRules Target, UEToolChain ToolChain, LinkEnvironment LinkEnvironment, CppCompileEnvironment CompileEnvironment, List`1 SharedPCHs, ISourceFileWorkingSet WorkingSet, ActionGraph ActionGraph) in D:\Build\++Shared\Sync\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\Configuration\UEBuildBinary.cs:line 593
1>                           at UnrealBuildTool.UEBuildBinary.Build(ReadOnlyTargetRules Target, UEToolChain ToolChain, CppCompileEnvironment CompileEnvironment, LinkEnvironment LinkEnvironment, List`1 SharedPCHs, ISourceFileWorkingSet WorkingSet, ActionGraph ActionGraph) in D:\Build\++Shared\Sync\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\Configuration\UEBuildBinary.cs:line 196
1>                           at UnrealBuildTool.UEBuildTarget.Build(BuildConfiguration BuildConfiguration, CPPHeaders Headers, List`1 OutputItems, List`1 UObjectModules, ISourceFileWorkingSet WorkingSet, ActionGraph ActionGraph, EHotReload HotReload, Boolean bIsAssemblingBuild) in D:\Build\++Shared\Sync\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\Configuration\UEBuildTarget.cs:line 2323
1>                           at UnrealBuildTool.UnrealBuildTool.RunUBT(BuildConfiguration BuildConfiguration, String[] Arguments, FileReference ProjectFile, Boolean bCatchExceptions) in D:\Build\++Shared\Sync\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\UnrealBuildTool.cs:line 1480
1>                        (see ../Programs/UnrealBuildTool/Log.txt for full exception trace)
1>C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\IDE\VC\VCTargets\Microsoft.MakeFile.Targets(44,5): error MSB3075: The command ""C:\Program Files\Epic Games\UE_4.20\Engine\Build\BatchFiles\Build.bat" rtg_clientEditor Win64 DebugGame "C:\_Development\Repositories\rtg\UE4\rtg_client\rtg_client.uproject" -WaitMutex -FromMsBuild" exited with code 5. Please verify that you have sufficient rights to run this command.
1>Done building project "rtg_client.vcxproj" -- FAILED.

I'm using a binary build of the engine, not my own built from source. Could this be a reason?

[John Alcatraz]

The Mixed Reality Framework seems less complete than 4.18 with no actual calibration map or function. Also, in the 4.20 P1 version notes, you state that there is a list of compatible cameras, yet in searching I could not come up with one. In my own test, the Logitech C920 works, but my Magewel USB3 HDMI (GEN 1) does not. The MrcVideoSource function sees it and gives me the correct video input of 'YUV2,1920x1080 60 FPS' which I have been able to create an instance of M_MrcVideoProcessing and tweak it for my green-screen background, but as soon as I do a 'VR Preview' it switches to NV12 640x460 50fps and video freezes, but the rest of the VR experience works normally. There also seems to be an aspect error issue as well, that was not seen in the Logitech C920 video output.

I definitely think the Mixed Reality Framework needs to be setup and documented in a way that its nice and easy to use. Twitch streamers that stream a VR game have to be able to get their camera into there (and have it calibrated correctly) with a few minutes of work, otherwise they won't do it.

So Epic, please make sure there is proper documentation for that!

[RVillani]

Packaging plugins always fails with a warning about the Expat lib and then an error about the module's ".precompiled" file not being found in the host project. Actually, while checking if it was there, I found that not even the Development folder was created inside Intermediate. I don't know if the Expat warning and the precompiled error are related.

The warning and the error are always the same, for both Android and Win64 (of course the paths have platform variations). The project is set to use the VS2017 toolchain and VisualStudio version is 2017 15.7.4

This is the warning:
UATHelper: Package Plugin Task (Windows): C:\Program Files\Epic Games\UE_4.20\Engine\Source\ThirdParty\Expat\Expat.Build.cs: warning: Referenced directory 'C:\Program Files\Epic Games\UE_4.20\Engine\Source\ThirdParty\Expat\expat-2.2.0\Win64\VS2015\Release' does not exist.

And this is the error:
UATHelper: Package Plugin Task (Windows): ERROR: System.IO.DirectoryNotFoundException: Could not find a part of the path 'A:\Libraries\Documents\Dev\Unreal Projects\EditorToolsDev1\Package\VillaniBlutilityExt\HostProject\Plugins\VillaniBlutilityExt\Intermediate\Build\Win64\UE4\Development\HISMActorExt\HISMActorExt.precompiled'.

[YuriNK]

Packaging plugins always fails

https://issues.unrealengine.com/issue/UE-61215

[RVillani]

https://issues.unrealengine.com/issue/UE-61215

Thanks for that! I found an issue but it was about your first complaints (wrong root folder), and it seems to have been solved. Hope this one also gets solved in the next preview. Voted.

[MagicBots]

I thought I saw it mentioned in a GDC talk that Epic would release the streamer they built for the ILM Xlabs raytrace demo for streaming to the Ipad to the general public in 4.20. Is this still in the plan? I don't see it on the list.