Unreal Engine Issues
Unreal Engine Issues
Niagara system loses source emitters when moving Engine from 4.22 or earlier to 4.23 or later.
UE - Niagara - Nov 29, 2019The following code causes this behavior.// NiagaraSystem.cpp for (FNiagaraEmitterHandle& EmitterHandle : EmitterHandles) { EmitterHandle.ConditionalPostLoad(NiagaraVer); if (!EmitterHandl ...
Niagara Particles in Mesh Shape Don't Render in Scene or Editor Preview
UE - Niagara - Dec 19, 2019Niagara particles aren't rendered in the Niagara Editor Preview or the scene when an emitter is in it. Found in 4.24.1 CL#10756747 Reproduced in 4.25 Main CL#10808197 ...
Setting an overlay's alpha to 0 does not display as fully transparent
Tools - Feb 19, 2020Safe zone overlay ignores alpha when set to 0.0 in DefaultEngine.ini. Tested: 4.23.1 CL#9631420 , 4.25 CL#11341939 ...
M_Volumetric_Sky_Prototype Material has compile errors
UE - Content - Engine - Mar 17, 2020The material "M_Volumetric_Sky_Prototype" has numerous compile errors that prevent it from being used. This was reported and tested in 4.25 Preview 2 (CL-12055273) and reproduced in 4.26 (CL-121923 ...
Duplicating BP actors reset edited Variables to Default Value if Variables name start with Chinese Character
UE - Foundation - Core - Jul 29, 2020Hints: It has no problem in 4.24, only happening in 4.25 It has no problem as long as the Variable name is contained with Alphabat(English characters) fully; or start with Alphabat(A_变量 is fine) ...
Problems in skeletal mesh merge
There are a few issues a licensee has found with the skeletal mesh merge operation. See the UDN for more details and the proposed fixes. Note, the issue with the cloth merge is already logged in a ...
bIgnoreAllPressedKeysUntilRelease only applies to keys in the previous mapping
UE - Gameplay - Input - Jun 16, 2022This is because the RebuildControlMappings function only checks this flag when you have a mapping that was already added, we should apply this for any new mappings as well. I'll update the repro s ...
Disabling bLerpUVs in Nanite Settings of Static Mesh causes texture warping in clusters
UE - Graphics Features - Nanite - Jan 21, 2025The licensee has identified a potential fix by changing if( Settings.bLerpUVs ) to if( Settings.bLerpUVs || UVIndex == 0 ) On line 389 of NaniteBuilder\Private\Cluster.cpp in UE 5.5 ...
Copy-pasting custom property nodes (ControRig etc.) results in invalid bindings, perf issues
UE - Anim - Rigging - Control Rig - Jul 28, 2025From this UDN: [Link Removed] Suggested fix:Override PostPasteNode to perform the GUID update andAdd validation on load to strip 'invalid' copies that do not correspond to a valid pin input ...
Crash copying Geometry Cache Track in Sequencer
UE - Anim - Sequencer - Aug 6, 2020Geometry cache section will crash in PostLoad when track is copied. See UDN for alternative repro steps and more info on attached repro project. ...