HZB Occlusion causes large stalls on the render thread

UE - Rendering Architecture - RHI - Oct 7, 2025

HZB Occlusion causes large stalls (greater than 5ms seen) on the render thread due to an RHI flush. This is caused by the following code in FDynamicRHI::RHIMapStagingSurface_RenderThread which force ...

An imported file that resides within the project's folders gets a relative path. That path is not updated it you copy the uasset to another folder. That breaks the Reimporting functionality.

UE - Editor - Content Pipeline - Import and Export - Aug 28, 2024

An imported file that resides within the project's folders gets a relative path. That path is not updated it you copy the uasset to another folder, so from the location of the new asset's the relati ...

Actors in sublevels do not replicate to Clients after Seamless ServerTravel

UE - Networking - Dec 9, 2015

Actors in sublevels do not replicate to Clients after Seamless ServerTravel. The user reporting this noted that "[...] UNetDriver::IsLevelInitializedForActor() keeps returning false even when the ac ...

Empty Shot Track Breaks Camera Component tracks when using Camera Cut Track

UE - Anim - Sequencer - Aug 18, 2016

Empty Shot Track Breaks Camera Component tracks when using Camera Cut Track ...

[Interchange] Crash on asset re-import

UE - Editor - Content Pipeline - Import and Export - Feb 7, 2025

We've started seeing a crash in editor when re-importing one of our assets. <pre class="ql-syntax">Assertion failed: (Index >= 0) & (Index < ArrayNum) [Link Removed] [Line: 783] Array index out of ...

Blueprint Struct Issues - Data table wiped data

UE - Gameplay - Blueprint Compiler - Aug 19, 2024

The user has come across various issues with using nested blueprint structs within a data table. The first issue relates to changing a variable in a child struct and setting it back then saving, cau ...

Editor crashes when creating a new level while the current level contains an Actor with an Actor Sequence Component

UE - Anim - Sequencer - Jan 5, 2022

This is not a regression. Tested in: //UE5/Main CL18218925 Binary - Crashed //UE5/Release-5.0 CL16682836 Binary - Crashed //UE4/Release-4.27 CL Binary - Crashed Having a level open that contains a ...

Animation Orientation does not Auto-Convert to UE4 Coordinates when Reimporting

OLD - Anim - Nov 23, 2015

Animation orientation does not auto-convert to UE4 coordinates when reimporting the same way it does when importing the same animation as a new import. In other words, a run animation generated from ...

Packaged Game crashes when using blend space that was added from the context menu

UE - Anim - Runtime - Anim Blueprints - Nov 16, 2021

Blendspace created within an animation blueprint from the context menu throws an assertion when packaged and ran. Only occurs in packaged projects. The blendspace will work correctly in PIE, and st ...

Crash after generating HLODs for merged meshes that have all triangles culled

UE - World Creation - Worldbuilding Tools - HLOD - Jul 25, 2024