Unreal Engine Issues
Unreal Engine Issues
Wrong calculation of "MaxAllocatedCountEstimate" inside FNiagaraRendererRibbons::GenerateDynamicData()
UE - Niagara - Mar 20, 2026Starting with UE 5.4, function FNiagaraRendererRibbons::GenerateDynamicData() from file [NiagaraRendererRibbons.cpp] attempts to calculate DynamicData->MaxAllocatedCountEstimate as such: DynamicDat ...
Binding to a Post Process AnimBP in Sequencer Causes MovieScene to Run Every Phase Every Frame
UE - Anim - Sequencer - Mar 20, 2026When binding to a Post Process AnimBP in Sequencer causes MovieScene to run the Spawn and Instantiation phase every frame. The code here explicitly looks at the AnimInstance on the Skeletal Mesh C ...
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 - Features - Shading Models - 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 - Runtime - Deformable - 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 - Runtime - Animation - 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 - Runtime - Deformable - 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 ...
Nanite Skeletal Mesh ignores Hidden Material Section flag
UE - Rendering - Graphics Features - Nanite - Mar 11, 2026Unlike non-Nanite Skeletal Meshes, Nanite-enabled Skeletal Meshes do not correctly respond to the Show flag passed via ShowMaterialSection(). Consequently, the Isolate checkbox for material slots in ...