Get Mouse Position Blueprint node returns different values outside of viewport depending on whether it was called from Event Tick, or within an Actor function

UE - Gameplay - Nov 15, 2018

There seems to be a discrepancy between the output of Get Mouse Position node depending on whether the node is inside an Actor function or called from Event Tick. If the node is present inside a fun ...

Wrong WPO motion vectors due to Periodic World Space node

UE - Rendering - Features - May 13, 2026

We've noticed smearing in grass due to wrong motion vectors. This appears to be caused by lack of previous frame support in the periodic world space node. This is how we fixed it: In MaterialTempl ...

Crash when casting to owner from AnimGraph

OLD - Anim - Sep 6, 2016

Crash occurs when casting back to the pawn owner from the Anim Graph. In this case, it is being used for "Copy Pose from Mesh" Workaround: Cast to Owner from Event Graph, defining variable as the ...

[CrashReport] Crash on Mac related to editor close

UE - Platform - Apple - Jun 6, 2017

This is a long-standing Mac crash that occurs with low frequency, but has affected more than 500 users since it started (possibly in the 4.11 release) It has recently been experienced internally by ...

Nanite: unused VertexInterpolator node disables Opacity Mask (material renders opaque)

UE - Rendering - Architecture - Jun 8, 2026

On Nanite meshes, placing a VertexInterpolator node in a material graph without using it (unconnected, or routed through a disabled static switch) silently breaks the Opacity Mask and the material r ...

ZenGarden or project with MSAA enabled crashes on iPhone 6 and 6+

UE - Platform - Mobile - Jul 19, 2017

Zen Garden crashes on the iPhone 6+ before anything appears onscreen. Occurred on: iPhone 6+ on 10.3.2 Didn't occur on: iPhone 6S on 10.3.2 ...

D3D12 Does Not Correctly Validate Static Uniform Buffers Correctly

UE - Rendering - RHI - Feb 12, 2025

When adding a Uniform Buffer Struct that has one 4x4 matrix to a mesh pass, validation will fail, due to a Uniform Buffer Struct mismatch. This can be reproduced by adding a mesh pass in project-si ...

Culling Distances Not Working For Static Mesh in Procedural Content Generation Tool and Foliage Tool

UE - Graphics Tools - PCG - Procedural Tools - Mar 28, 2025

When creating Foliage or Procedurally Generated Content the culling settings of the Static Meshes do not apply correctly. As soon as either a minimum or maximum cull distance is set the Static Meshe ...

In editor, sub level instance's streaming state persists incorrectly after toggling Level Behavior without saving

UE - Engine Scaling - Streaming - Level Instances - Jun 11, 2025

When adding a sub level with world partition streaming to a main level where the streaming is also enabled, setting* Level Behavior* of the sub level to Standalone, and saving the result, in the fir ...

Import Source disappears in Textures after loading asynchronously loaded level

UE - Editor - Content Pipeline - Import and Export - Dec 15, 2015

It looks like when reimporting a texture asset into the engine after loading a level, you will be confronted with the File Selection box and not the reimport successful notification. In fact if you ...