UIScaleCurve float-point value in BaseEngine.ini lacks precision

UE - Editor - UI Systems - Slate - Jun 4, 2020

The screenshots below display 1920x1080pixel widget button. First one with Default DPIScaleCurve shows extra borders on the right and bottom. Next one with more precision shows no extra boundary. [ ...

The HISM will have double drawcalls when player opens r.Mobile.AllowDitheredLODTransition

UE - World Creation - Worldbuilding Tools - Foliage - Nov 2, 2020

Please check the Function GetDynamicMeshElements in HierarchicalInstancedStaticMesh.cpp. The  Function Traverse in GetDynamicMeshElements will always return two Lod levels, even the transition is f ...

Setting a float variable to a value that's beyond the maximum value of a float causes the editor to become unresponsive

UE - Editor - UI Systems - Localization - Nov 12, 2021

When inputting an extreme large value into a float variable that exceed the maximum value of a float, the engine then becomes unresponsive. I tested this with an integer variable and this did not oc ...

.mp4s cannot be played in default projects in UE5.

UE - Media Framework - Apr 6, 2022

In UE4 (using DX11), WmfMedia was able to play .mp4 files by default. However, WmfMedia doesn't support playing .mp4s in DX12, which is what is used in UE5. Electra can handle playing .mp4s in UE5, ...

When TSR is enabled, the maximum brightness is clamped to about 16000.

UE - Graphics Features - Jun 7, 2022

You can also check it by enabling real-time rendering in the NewMap.umap of the attached project, and then clicking on "High Resolution Screenshots". (You may need to disable and enable post-process ...

Chaos : Rigid body sleeps when very small external force is applied by AddForce

UE - Simulation - Physics - Solver - May 25, 2022

When a small external force is applied to the rigid body, the VSmooth value is reset in the ResetVSmoothFromForces function. Since this function ignores the current velocity, a very small velocity ...

InstanceOnly UProperties accessible in Blueprint

UE - Gameplay - Blueprint Editor - Nov 30, 2022

Reproduced 3/3 times. Issue does not occur in //UE5/Release-5.0 - CL 20979098 Binary. Confirmed Regression. ...

Atmosphere related scan line artifacts for Path Tracer with MGPU

UE - Graphics Features - Path Tracer - Feb 10, 2023

There are two UDNs related to this issue.  It makes the Path Tracer unusable with MGPU, with atmosphere enabled. I already have a one-line fix implemented and tested.  The atmosphere scan line arti ...

When change a skeletal's collision from QueryOnly to QueryAndPhysics at runtime, dynamic properties won't be updated

UE - Simulation - Physics - Aug 23, 2023

It seems in the FBodyInstance::InitDynamicProperties_AssumesLocked, we early out when the body instance's collision is QueryOnly, but actually we only recreate its physics state when changing from N ...

Build All Levels fails with duplicate level instances

UE - World Creation - Worldbuilding Tools - Level Instances - Jan 24, 2024