Nanite TwoSidedSign is backwards

UE - Graphics Features - Nanite - Apr 10, 2025

The value of MaterialExpressionTwoSidedSign is flipped when calculating the Opacity Mask for Nanite meshes. This seems to be a regression in 5.5. ...

Replication default setting of child blueprint resets if parent is compiled

UE - Gameplay - Blueprint - Jul 20, 2015

The setting for Replication on a Blueprint variable resets to None of the Blueprint's parent BP is compiled. ...

Changing UPROPERTY() settings causes detail components to vanish in editor

Tools - Mar 11, 2015

When a UPROPERTY() macro is changed and the recompiled, the hot reload in the editor will cause any BP based on the class to lose certain aspects of the Detail panel such as the actor's transform. ...

Static mesh loses static mesh reference when Alt-dragged in viewport if filepath contains []

Tools - Sep 3, 2015

Static meshes lose their static mesh reference when alt-dragged in viewport. This only occurs if the mesh is located in a filepath containing square brackets ( [] ) within the filepath name. Additio ...

Interface cannot be re-implemented after removal from blueprint

UE - Gameplay - Blueprint - Sep 1, 2015

If an interface is removed from a blueprint and an interface function is transferred to a local function, the interface cannot be re-implemented in the blueprint. ...

nonstandard bsp additive brushes cause breaking/artifacting on other bsp brushes when colliding

UE - LD & Modeling - Modeling Tools - BSP - May 14, 2015

if a nonstandard additive bsp brush collides with a standard additive bsp brush, the surfaces of the bsps break and artifact, causing numerous holes in the brushes. ...

Changing between multiple Streams that are contained within an array does not work

UE - Gameplay - Blueprint - Mar 20, 2015

Changing between multiple Streams that are contained within an array does not work. ...

Using Bake Material Position Offset Into Collision causes landscape to have no collision

UE - LD & Modeling - Terrain - Landscape - Jan 13, 2016

Creating a material with World Position Offset and enabling "Bake Material Position Offset Into Collision" causes the landscape to have no collision. Disabling this feature causes collision to come ...

Editor crashes when attempting to open a new level from a level that has an external curve in a timeline within the level blueprint

UE - Gameplay - Blueprint - Oct 27, 2014

The editor crashes when a user imports a float curve into a timeline within the level blueprint then attempts to open another level. ...

UMG widgets aren't cleared when levels are swapped via 'open LevelName'.

UE - Editor - UI Systems - Oct 30, 2014

If a level has UMG widgets, swapping to other levels (including the level you're already on) doesn't clear away the UMG widgets. ...