Unreal Engine Issues
Unreal Engine Issues
Curve Retargeting does not work with SourcePose retarget mode
UE - Anim - Rigging - Retargeting - Jan 14, 2026Currently we build what source curves we are going to remap is done inside of: FIKRetargetCurveRemapOp::AnimGraphPreUpdateMainThread But in our ikretarget processor code we skip calling that functi ...
HISM flickering when any character is visible
UE - Graphics Features - Jan 12, 2026On an NVIDIA GPU, Instanced Static Meshes can flicker when a Groom card or mesh LOD is visible. This appears related to an issue rendering the ISM into the Scene Depth. At the end of the Prepass, t ...
MultiProcessCook Shader Symbols fail to write when two workers race and try to write them at the same time
UE - Foundation - Data Pipeline - Cooker - Jan 4, 2026When shadersymbols are requested, cooking shaders writes the symbol files into {Project} /Saved/ShaderSymbols/<PlatformName>. These symbols are written by the function FShaderSymbolExport::Write ...
Virtual Memory leak when using specific rendering settings in the template project
UE - Rendering Architecture - RHI - Dec 20, 2025When a project is run with these settings in a template project, untracked virtual memory increases. Cvars r.GBufferFormat 3 r.Lumen.TraceMeshSDFs 1 r.Lumen.TranslucencyReflections.FrontLayer.Enab ...
Skeletal Mesh BLAS updates when not animating
UE - Rendering Architecture - 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 ...
Call In Editor functions not working in blueprints
UE - Editor - Developer Usability - 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 ...
Editor localization causes the GetLinkedAnimLayerInstanceByGroup function to fail in retrieving the corresponding LinkedAnimLayer within the editor.
UE - Anim - Runtime - Anim Blueprints - 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 ...
ActorComponents registered with wrong world from UWorldPartition::ApplyRuntimeCellsTransformerStack
UE - World Creation - Worldbuilding Tools - 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 - Simulation - Gameplay - 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 ...
[AI] StateTree fails to compile after copy/pasting a state with a task that binds to required event on the state's enter conditions
UE - AI - StateTree - Dec 14, 2025StateTree appears to keep an incorrect reference to the event from the source tree rather than re-establishing the property binding to the new tree's event. This happens when copy/paste of the state ...