ComponentOverlapMultiByChannel with a rotated simple collision PrimComp misses overlap vs. complex collision

UE - Runtime - Simulation - Nov 8, 2023

UWorld::ComponentOverlapMultiByChannel and internally, the call to FBodyInstance::OverlapMulti, misses overlaps and blocking hits when the PrimComp's (the component used to test overlaps) mesh uses ...

Different Number of Frames imported from the same FBX between UE 4.8 and 4.9

OLD - Anim - Sep 14, 2015

Using the same import settings in UE4.8 and UE4.9 will result in a different number of frames of an animation being imported from the same FBX file. If you import the same fbx animation which in M ...

Instanced object in an array property of an actor component is invalidated and marked for garbage collection on undo

UE - Gameplay - Jun 4, 2024

If an actor component contains a TArray of instanced objects, some of those object instances can get incorrectly invalidated and marked for garbage collection in certain situations, possibly resulti ...

Division by zero causing NaN/Inf on USkeletalMeshComponent::UpdateRigidBodyScaling() when setting scale to zero and back

UE - Runtime - Simulation - Feb 11, 2026

Up to UE 5.5, skeletal mesh physics did not get updated when the component's scale changed. This was improved on January 2025 with CL 39190335, which addressed [Link Removed] ...

Failed to build in Github UE4.27.0.

UE - Runtime - Simulation - Aug 30, 2021

Failed to build UE4.27.0 with Win64/Development Editor.  Can avoid this error that excluding the project from build configuration. (Solution UE4->Properties->Configuration Properties->Configuratio ...

Assigning APX Cloth asset to material element

UE - Simulation - Physics - Character - Jun 17, 2016

When assigning an imported apx file to the clothing drop down under the material element of this imported Skeletal Mesh will result in a crash. Tested in: 4.11.2 CL-2946394 4.12.3 CL-3013449 Dev ...

UPlacementSubsystem does not respect AssetFactories priorities, which is inconsistent with UEditorEngine::ActorFactories and makes it impossible to override placed actor type when dragging asset from Content Browser to Level Editor Viewport.

UE - Editor - Workflow Systems - Mar 30, 2026

Note: This issue was reproduced in UE 5.7, and it works correctly in UE 4.27. Prior to CL 24938100 (between UE 5.1 and 5.2), all existing factories were discovered and registered during engine init ...

When playing matinee, scrubbing can cause sound to keep playing when it isn't triggered

UE - Audio - May 31, 2016

When playing matinee, scrubbing can cause sound to keep playing when it isn't triggered Note: This was entered as a bug to re-work the fix from the pull request found here: [Link Removed] ...

IPA Package Sizes have Increased between Versions

UE - Platform - Mobile - Feb 21, 2017

When packaging for iOS the IPA file seems to have increased in size from previous versions. The licensee made an important observation that it appears the master materials have almost halved in si ...

Package fails for android if company name begins with a number

UE - Platform - Mobile - Apr 26, 2017

If the company name has a number at the beginning of it when packaging for android it returns a series of errors and does not allow the project to be built. The error that is being shown in the outp ...