Incorrect restitution behavior for physical material set to 1 whereby momentum is gained during the simulation

UE - Simulation - Physics - Mar 24, 2015

Setting a restitution of 1 for a ground material and a restitution of 1 for a ball that bounces on the ground should keep the ball bouncing at the same height consecutively. Over the course of time ...

Collision Channel on Particle Systems not saving

UE - Graphics Features - Oct 21, 2014

Setting the Collision Channel to anything other than World Static will reset on closing and restarting the editor. ...

The drawing order of widgets becomes wrong when GlobalInvalidation is enabled,

UE - Editor - UI Systems - Slate - Nov 26, 2021

When trying to create a widget with specific steps, the drawing order may not be correct. This is not reproduced when Global Invalidation is disabled, and the state can be restored. This issue is pr ...

Incorrect number of vertices displayed by ProfileGPU command in Cascade particles

UE - Niagara - Dec 9, 2021

This issue was reported by the licensee, but it's possible that the number of vertices in the particles is higher than it really is. ...

Destructible attached with a Physics Constraint ignores Start Awake on play

UE - Simulation - Physics - Destruction - Jul 26, 2016

Destructible attached with a Physics Constraint ignores Start Awake on play The Destructible component is set to simulate physics, but on play physics is not simulated unless the destructible is to ...

"Out of video memory" crash when attempting to save many assets with source control enabled

UE - Graphics Features - Sep 25, 2020

This will only repro when connected to source control ...

Using "Play Animation" node, if current animation has a looping timed particle it will continue playing

OLD - Anim - Jun 24, 2016

Calling "Play Animation", if current animation has a looping timed particle it will continue playing ...

Unexpected behavior with Broken Constraint and Physics Blend Weight

OLD - Anim - Jan 13, 2017

Looks like the position of the bone according to the animation is still being accounted for somehow, because the collision seems fine (when using pxvis collision). ...

FileSystemDerivedDataBackend may output a corrupted access log

UE - Foundation - Core - Derived Data - May 20, 2021

This problem is caused by the AccessLogWriter has not been flushed at the termination. The following workaround flushes the Writer.class FFileSystemDerivedDataBackend : public FDerivedDataBackendInt ...

Crash when a Deferred Decal (Translucent) base material has a Nanite Override (Masked Surface) Material and the mesh has Nanite + Ray Tracing enabled.

UE - Graphics Features - Ray Tracing - Aug 14, 2025

A crash occurs when Nanite override material instance is used in a project with Ray tracing enabled where: 1 The Material assigned to the static mesh uses Deferred Decal / Translucent and the Nani ...