Unreal Engine Issues

Unreal Engine Fails to Launch with Vulkan SM6 RHI and RenderDoc Auto-Attach Enabled

When launching Unreal Engine with the Vulkan RHI, SM6 and RenderDoc Auto Attach on Startup enabled, the engine fails to initialize with the error: “A compatible Vulkan Driver is required to run the ...

SaveGeneratedTexture2DAsset can crash when overwriting an existing asset

SaveGeneratedTexture2DAsset can crash for a variety of reasons when overwriting an existing texture asset. When no existing asset exists, the function simply moves the provided transient Texture ass ...

Unshelving a file from Unreal locks unreal. Killing process leaves the file locked and can't be checked out

Unreal currently locks any assets that are loaded. Actions such as "revert" from within the editor handle this properly by unloading the asset but unshelving from within the editor does not respect ...

Client Gameplay Effect stuck on due to duplicate ReplicationIDs

We've been tracking down a problem recently with the Gameplay Ability System where a gameplay effect is properly removed on the server, but the client has the gameplay effect stuck on permanently. ...

TOptional value changes in parent BP don't propagate to loaded child BPs

Context TOptional<T> is a wrapping struct around a type, that lets the property have an set and unset state, in addition to the property's value when set. It is editor exposed: designers can open b ...

HZB Occlusion causes large stalls on the render thread

HZB Occlusion causes large stalls (greater than 5ms seen) on the render thread due to an RHI flush. This is caused by the following code in FDynamicRHI::RHIMapStagingSurface_RenderThread which force ...

Custom Depth range is different than Pixel Depth range

Shaders that compare custom depth and pixel depth get wrong output values because the ranges are different. This error is most noticeable over large distances. The difference in ranges is due to t ...

LODs with screen size 0 in legacy assets are incorrectly converted to 1 on load

When loading a mesh asset (static or skeletal) created in an old version of Unreal (e.g. 4.10), any LOD whose LOD screen size was originally set to 0, is converted to 1. This causes LODs that would ...

Some operations on material instances do not transmit over transactions.

DirectoriesToAlwaysCook in platform specific configuration files are ignored by the cook process

When DirectoriesToAlwaysCook is placed in a platform-specific configuration file, the cook process does not read that entry when cooking content for that platform. The editor is aware of the platfo ...