Unreal Engine Issues
Unreal Engine Issues
Invalid GUIDs on new material instance parameters cause overrides to break on base param rename
UE - Rendering - Architecture - Materials - Sep 3, 2025When a parameter value is assigned on a newly created material instance (constant or dynamic) using Set***ParameterValueInternal, the parameter’s ExpressionGUID is left invalid (0,0,0,0). Parameter ...
LIVE: Manually importing a single LOD created in Maya will rotate -90 degrees
UE - Editor - Content Pipeline - Import and Export - Nov 5, 2014DESCRIPTION: When importing a mesh created with Maya then saving, closing, and reopening the editor, if you add a LOD via the right mouse menu or mesh editor will result in the LOD importing -90 rot ...
Packaging a runtime plugin in a Blueprint project causes some Editor files to be deleted
UE - Foundation - Cpp Tools - Oct 22, 2018Attempting to package a runtime plugin (does not occur with a Development plugin) in a Blueprint project fails in 4.21 Preview 2. This also causes some Editor files to be deleted, including the Modu ...
Updating Material does not update platform stats in derived Instance
UE - Rendering - Architecture - Materials - Nov 26, 2024It would seem that updating a material does not update the associated platform stats in a material instance editor, only the parameters. Can workaround by manually invoking shader compile in the ma ...
Enabling ZenLoader causes editor crash when undoing Level Instance deletion
UE - Core - Systems - Sep 5, 2024Crash reported through UDN. With ZenLoader enabled, deleting a level instance and triggering Undo causes a crash in ULandscapeComponent::PostEditUndo() The user has provided an example project th ...
Physics Constraint no longer constrains components that are set to Query Only
UE - Gameplay - May 5, 2016Physics Constraint no longer constrains conponents that are set to Query Only Regression from 4.11.2 User Description: Testing a 4.12 copy of my 4.11 project and when I tested in editor, all my ...
GPU Particle Collision causes shaking when set to bounce with low resilience.
UE - Niagara - Jul 27, 2016A particle emitter with GPU sprites on certain settings will shake violently as they collide with the ground. This requires there to be a strong Const Acceleration module and Collision with low resi ...
SpeedTree Material No Longer Compiles With Texture Coordinate Node In BaseColor
UE - Graphics Features - Jan 25, 2017If you open a material with the speedtree node plugged into WPO and then use a texture coordinate(index of 2) in base color the material will no longer compile properly. The full error is "Error [ ...
Iris - large fast arrays serialize multiple elements when only one is dirtied
UE - Networking - Iris - Apr 8, 2025This seems to be a result of how the changemask is handled for fast arrays. Because the changemask is a fixed set of bits (defined by IrisFastArrayChangeMaskBits), a single bit can represent multipl ...
Substrate: FPrimitiveViewRelevance::operator|= bitwise-ORs SubstrateUintPerPixel, inflating the per-pixel byte count and asserting under the blendable GBuffer
UE - Rendering - Features - Shading Models - Oct 6, 2026A crash can occur due to this check in Substrate.cpp when a material with 2 units and a material with 5 (20 bpp) uints are combined triggering :check(CurrentMaxBytesPerPixel <= PlatformSettingsBytes ...