Some post-processing passes sample outside of the viewport when using scene capture components

UE - Rendering - Features - Nov 29, 2023

It looks like the SSAO shader does not clamp its sample space to the half view size for the two inputs "Ambient Occlusion" and "AmbientOcclusionSetup", leading to invalid data entering the edge of f ...

Chaos sometimes can not generate contact points while two dynamic convex hulls actually collide. It results in instability in the contact behavior​ - such as jittering, inconsistent contact forces, or unexpected collision responses.

UE - Runtime - Simulation - Dec 2, 2025

Context: Chaos Physics is able to use convex hulls to represent object collision geometry for queries and simulation. Problem: Chaos sometimes can not generate contact points while two dynamic conv ...

BP timelines: when converting internal curve to external, the external curve isn't used until BP is recompiled

UE - Framework - Blueprint Editor - Aug 28, 2023

Blueprint timelines: when converting an internal curve to an external curve asset, the curve asset's data isn't used until the blueprint is recompiled. This is confusing as there is no indication th ...

Property Editors fail to import text values for FKeys within array/set/map containers when the key is identified by some valid non-alphanumeric characters

UE - Gameplay - Input - Oct 28, 2024

The FKey structure represents a user action input such as a keyboard key, a mouse button/wheel, or a gesture in VR. For the keyboard, it can represent any pressable key, such as letters, numbers, sy ...

Lumen Global Distance Field Trace Leaking due to Surface Cache Sampling

UE - Rendering - Features - Jan 12, 2026

At specific distances from a thin wall, surfaces inside of a sealed chamber can receive indirect lighting from outside, leaking light into the chamber. This appears to be due to how SWRT handles sa ...

Play Media Player Node Causes Blueprint Functions to be Uncallable

UE - Gameplay - Blueprint - Feb 23, 2016

This only occurs in standalone or a packaged game Having a Play Media Player node in a blueprint causes all of that blueprint's functions to become uncallable. Found in 4.11 Preview 5. Reproduced ...

[Sound Submix] - Dry Level of a Submix is calculated differently whether or not there is an effect in the chain

UE - Audio - Submixes - Jan 21, 2021

There is a discrepancy is how the output volume of a submix is calculated when the effect chain is and is not populated. When there is no effect on the submix, the Dry Level adds additional gain to ...

Global SkyAtmosphere and Clouds Issues (Cloud Shadows)

UE - Rendering - Features - Dec 3, 2024

Sampling Cloud Shadows when rendering the Sky Atmosphere can incorrectly assume that the view is located at the planet's North Pole. This causes distortion in the shadows when using a sphere-shaped ...

Blueprint with instance static mesh from construction script will cause crash when using the build then build geometry

Tools - Mar 12, 2015

When using a BP with component instance static mesh that is added via the construction script, when using the build button in the toolbar to build lighitng and geometry everything will work correctl ...