Material Layers Ignore Virtual Texture Sampler Restrictions

UE - Rendering - Architecture - Mar 25, 2024

Virtual Textures can be assigned to Texture Sample Parameters that are not configured for Virtual Textures, if that parameter is inside of a Material Layer. Also found in Release-5.4, CL 32426910 ...

Translucency area has stripe-style issue on TSR

UE - Graphics Features - Mar 28, 2024

The TSR History Rejection buffer develops a grid-like artifact over translucent, camera-facingplanes. This problem can be mitigated by increasing r.TSR.ShadingRejection.TileOverscan from 3 to 4 with ...

When a Niagara User Parameter is renamed, mesh bindings on Niagara Mesh Renderers are not updated, and the binding is silently broken

UE - Niagara - Mar 13, 2025

In Niagara, Mesh Renderers expose a "Meshes" array for selecting the meshes to be rendered. On each array entry, a property "Mesh Parameter Binding" is available and allows the user to override that ...

Multiple setter functions in UMaterialEditingLibrary always return false even when the parameter is correctly set on the MaterialInstance.

UE - Rendering - Architecture - Materials - May 30, 2025

In Unreal Engine, materials can expose parameters that can then be modified via instances (MaterialInstanceConstant). The UMaterialEditingLibrary provides several functions to modify these parameter ...

Mutable compile hangs indefinitely when using Customizable Object Extension Data Constants

UE - Anim - Mutable - Oct 25, 2025

I am getting a CO compile to hang indefinitely while compiling. It seems to be caused by the optimization in LocalLogicOptimiserAST that tries to convert 3+ conditionals into a switch statement. It ...

Occlusion Queries for Static Meshes with ERuntimeVirtualTextureMainPassType::Exclusive

UE - Rendering - Architecture - Feb 20, 2026

Static Meshes that draw into RVTs and have "Draw In Main Pass" is set to "From Virtual Texture" (ERuntimeVirtualTextureMainPassType::Exclusive) will still draw in Occlusion Queries. This can be tr ...

Input pins of BP node are not updated after a hot reload

UE - Gameplay - Blueprint - Apr 17, 2015

If a code defined function that takes in a parameter is called from blueprints, the BP node will show the input pin for the parameter. If the parameter list is changed after the node is created and ...

Construction script on child actor components not respected in PIE

UE - Gameplay - Blueprint - Jan 14, 2016

Child Actor Components run their construction scripts upon parent's placement in level. However, these specifications are not maintained once PIE is initiated. ...

promoting a variable to a local variable in another blueprint creates compile error.

UE - Gameplay - Blueprint - Sep 30, 2015

If a local variable set variable is copied/pasted over to a second blueprint and the input pin is promoted to a local variable, compiling the blueprint will cause a compile error to appear until the ...

Duplicate slots being created in Anim Slot Manager

OLD - Anim - Dec 11, 2015

Duplicate slots are being created automatically under the Default Group in the AnimSlotManager. This is causing some problems because it replaces the originally created slot with the duplicate in t ...