Unreal Engine Issues
Unreal Engine Issues
Camera tangent inversion on FBX Import when "Force Front XAxis" is enabled
UE - Anim - Sequencer - Mar 19, 2026When importing camera animation FBX files into Sequencer, enabling the "Force Front XAxis" option causes the key tangents for Rotation-Pitch (Y) to be inverted. This results in broken animation curv ...
Substrate Unlit editor view mode renders black with Blendable GBuffer
UE - Rendering - Graphics Features - Substrate - Mar 18, 2026When using Substrate materials with SUBSTRATE_GBUFFER_FORMAT==0 (Blendable GBuffer), the Unlit editor view mode renders completely black. TopLayerData.UnlitViewBaseColor is never populated in the bl ...
Control Rig Physics world collision fails against ISM component meshes
UE - Anim - Synthesis - Physics Control - Mar 17, 2026CRP currently fails to collide against the bodies generated by ISM components. This is because the collision body data is stored in a different property for ISMs vs regular primitive components. ...
Skeletal Mesh Cloth - Removing cloth collision sources doesn't remove the prerequisite, and the collision sources are not updated
UE - Simulation - Visual - Mar 17, 2026[Link Removed] See proposed fix from partner: [Image Removed] ...
Dangling pointer + mem corruption related to OwnerLastRenderTimePtr
UE - World Creation - Worldbuilding Tools - Mar 16, 2026We've been seeing asserts and crashes related to OwnerLastRenderTimePtr. We've traced this to the mentioned pointer ending up dangling after using UActorComponent::Rename() on primitive components t ...
AnimNotify serialization crash in editor
UE - Anim - Runtime - Mar 15, 2026The crash is caused by changing the variable type of an AnimNotify that is already referenced by a montage. This issue cannot be reproduced in 5.6. ...
GroomComponent: SetVisibility(false) causes per-frame simulation reset instead of stopping it
UE - Simulation - Visual - Mar 12, 2026UGroomComponent::TickComponent sets bResetSimulation = true every frame when the component is not visible. This causes NiagaraDataInterfaceHairStrands to triggering a full simulation reset every fra ...
Frame-locked sequencer intermittently triggers notify state end event
UE - Anim - Runtime - Mar 10, 2026Frame-locked Sequencers can occasionally produce frames with a zero delta time due to frame number truncation. When this occurs, if the animation cursor is within the range of a Notify State that is ...
Sequencer CR curve evaluating differently when navigating from parent sequence
UE - Anim - Anim in Engine - Mar 10, 2026Depending on whether I first open the level sequence that contains the control rig, or its parent level sequence, the animation curve will evaluate differently. ...
LevelStreamingPersistence: BP variables that aren't Instance Editable get reset
UE - World Creation - Worldbuilding Tools - Mar 6, 2026Context The LevelStreamingPersistence plugin can be used to remember and restore properties on actors and components that are part of a streamed level. Blueprint variables can be marked as instan ...