Unreal Engine Issues
Unreal Engine Issues
Skeletal Mesh BLAS updates when not animating
UE - Rendering - RHI - Dec 19, 2025The BLAS for Skeletal Meshes that don't move, or tick get updated every frame even if the animation and skin cache aren't updated. This adds over 1ms to update time. The only exception is if the sk ...
When r.SSR.Stencil is enabled, there is wrong logic observed.
UE - Rendering - Features - Dec 19, 2025When r.SSR.Stencil is enabled, the areas with high roughnesss are not discarded and Unlit materials are incorrectly handled. See the linked EPS case (Additional Info URL) for a full explanation of ...
Call In Editor functions not working in blueprints
UE - Editor - Dec 19, 2025Context When selecting a component on an actor, any CallInEditor functions on the component's class appear as buttons in the details panel. Problem The CallInEditor functions don't execute in Blu ...
Changing bIsSpatiallyLoaded can cause an Actor to be duplicated during Play-In-Editor
UE - Engine Scaling - Streaming - World Partition - Dec 18, 2025Changing bIsSpatiallyLoaded can cause an Actor to be duplicated during Play-In-Editor. As described in the steps to reproduce, if we keep swapping bIsSpatiallyLoaded state and save a Streaming Level ...
Editor localization causes the GetLinkedAnimLayerInstanceByGroup function to fail in retrieving the corresponding LinkedAnimLayer within the editor.
UE - Runtime - Anim BP - Dec 18, 2025When using other language(such as Chinese) as editor language, the Group Name of the Animation Interface will be localized to Chinese. In editor, the animation blueprint grab the group from metadata ...
If a child blueprint class has an Instanced/EditInlineNew object property, that property will always be detected as changed by the property editor (i.e. it will show a "Revert" arrow on that property), even if its properties are identical to the parent.
UE - Framework - Blueprint Editor - Dec 17, 2025Context: Blueprint classes can use Instanced/EditInlineNew object property specifiers to create and edit subobjects directly in the editor. Problem: If a child blueprint class has an Instanced/Edit ...
Section::TrimSection resulting in bad key values at start and end of trim range
zComponent - Archive - Dec 17, 2025The trim process inserts keys at the start or end of the range depending if you specify Trim Left or Right, I'm finding that Trim right is inserting a key at the end of the section that is incorrect ...
[WorldPartition][CellTransformer] ActorComponents registered with wrong world from UWorldPartition::ApplyRuntimeCellsTransformerStack
UE - Engine Scaling - Streaming - World Partition - Dec 17, 2025There is a risk of actor components registering with the wrong world when reconstructed from UWorldPartition::ApplyRuntimeCellsTransformerStack. The repro case is arguably a bad usage, but it was th ...
A chaos vehicle that moves at very high speeds with CCD enabled on the vehicle sometimes has a collision response that is abnormal where the vehicle loses a significant amount of speed when colliding with dynamic objects configured as One Way Interaction
UE - Runtime - Character - Dec 16, 2025Context: Continuous Collision Detection (CCD) is being used on a Chaos Vehicle to avoid tunneling issues with certain surfaces as it prevents any missed collisions between fast moving particles and ...
Paper2D: Editor hangs when assigning Sprite Atlas Group to Sprite
UE - Gameplay - Paper2D - Dec 16, 2025In UE 5.3 and later, assigning a Sprite Atlas Group to a UPaperSprite asset can cause the editor to hang and eventually crash. This behavior has been reproduced in 5.3, 5.6, and a recent UE5-main so ...