Crash when enabling dynamic branch on static switches in Post Process Materials

UE - Rendering Architecture - Materials - Jun 28, 2023

[Link Removed] Some functions to access parameters don't take into account the newly added runtime static switch parameters. It should be straightforward to fix these up: void UMaterialInstance:: ...

Niagara - When Interpolated Spawning is disabled, the first frame of each particle unexpectedly does not take into account the Particle Update stage

UE - Niagara - Feb 28, 2025

Foreword: Even if the behavior described here is by design, it is rarely (if ever) expected or desired. This was discussed and agreed to be treated as a bug. Explanation below. When interpolated sp ...

Material expression If node has been broken, major regression that shipped in 4.6

UE - Graphics Features - Dec 9, 2014

This sounds legit. Anyone mess with the if node recently? There seems to be a regression where existing content is broken. This should be fixed ASAP and patched into 4.6. https://forums.unrealen ...

MaterialTextureScale calculated incorrectly for materials with WorldPositionOffset

UE - Rendering Architecture - Materials - Apr 16, 2024

When a Material uses WorldPositionOffset, the MaterialTextureScale is calculated incorrectly because FMaterialUtilities::ExportMaterialUVDensities() calls FMeshRenderer::RenderMaterialTexCoordScales ...

Multiple Materials not assigned to Mesh on Import

UE - Editor - Content Pipeline - Import and Export - Jan 6, 2017

Not all material elements are created and assigned to the static mesh using multiple materials. With the attached mesh, only the first element is created and the other two are left non-existent. I c ...

Blueprint Editor: BP functions display dropdown instead of checkboxes for uint8 enum parameters

UE - Gameplay - Blueprint Editor - Aug 8, 2017

I traced through the callstack and it looks like the problem is as follows:in order for the BP function to compile, its enum parameter must be uint8, because that is the only type supported by BP fu ...

Each adding a static mesh not containing any collision data keeps increasing PhysX memory

UE - Simulation - Physics - Apr 19, 2021

If the static mesh has UseSimpleCollisionAsComplex and does not have any SimpleCollision shapes, The physics actor will be destroyed immediately in FInitBodiesHelperBase::CreateShapesAndActors, but ...

TextRenderComponents not parallel safe. Can cause crash

UE - Graphics Features - Feb 28, 2017

Licensee has reported intermittent crashes when loading a map that contains Child Actors with Text Render Components. When the child actor blueprint is spawned all of the text render components st ...

UE4 Crashes if multiple Vive Trackers or Lighthouses are used

UE - Platform - XR - Jan 24, 2018

User reports that if more than 5 trackers are connected, UE4 crashes Suggested fix: Root cause of bug is related to the fact that UE has no setup to receive input events from Vive Trackers. (we ha ...