Deleting struct in Windows Explorer leaves dirty traces in BPs.

UE - Gameplay - Blueprint - Mar 3, 2020

UND: https://udn.unrealengine.com/questions/559972/invalid-map-in-blueprint-unable-to-be-deleted-urge.html If you delete a struct in Windows Explorer manually, then open a project/BP, it will ask t ...

Particles are only activated when the camera moves back

UE - Niagara - Mar 3, 2020

UParticleSystemComponent :: CanConsiderInvisible () Particles determined to be invisible by MaxSecondsBeforeInactive seem to be activated only when the camera moves back. Is this correct behavior? ...

The SetEmitterEnable BP function needs implementation

UE - Niagara - Mar 2, 2020

The BP function calls FNiagaraSystemInstance::SetEmitterEnable, which sets ExecutionState on the emitter instance to ENiagaraExecutionState::Inactive. FNiagaraSystemSimulation::PrepareForSystemSimul ...

Building a patch from the project launcher will crash unrealpak when pak encryption is enabled

UE - Foundation - Core - Mar 2, 2020

When using unrealpak to make a patch, if the source pak data that a patch is based from is encrypted, you must specify the "patchcryptokeys" parameter on the command line so unrealpak knows which cr ...

Rare assertion comes up when cooking if sequencer camera track has only additive transform track

UE - Anim - Sequencer - Mar 2, 2020

If a camera track has only additive transform track, some functions return uninitialized F3DTransformTrackToken made by default constructor. It causes a rare assertion. Please take a look at F3DTra ...

Niagara Ribbon Facing Mode Custom Side Vector does not work correctly

UE - Niagara - Feb 28, 2020

The Custom Side Vector facing mode is no different than the Custom facing mode on Niagara ribbons. The linked UDN has more information on a potential cause, as well as a proposed fix. It looks like ...

Widget With Spinbox Crashes When Destrcutor Is Called With Multithreaded Destruction Enabled

UE - Foundation - Core - UObject - Feb 28, 2020

When a widget with a spinbox is calls it's Destructor with "Multithreaded Destruction" enabled the engine crashes. I have tested in 4.23.1, 4.24.3, and 4.26 Main with "Multithreaded Destruction" dis ...

Changing the engine quality settings will cause the editor to crash

UE - Graphics Features - Feb 27, 2020

Changing the engine quality settings to low or medium will cause the editor to crash  This was tested in 4.24.3 @ CL 11590231 and doesn't occur, so this is marked as a regression.  Mac Environme ...

Crash if the number of spline points is less the one spline point currently selected

Tools - Feb 26, 2020

Spline components with "input spline points to construction script" enabled causes crash when selecting a spline point and reducing the total number of spline points below the selected spline. Te ...