Unreal Engine Issues
Unreal Engine Issues
Many downloaded cloud items cause a performance issue when booting Twinmotion
TM - Interoperability - Sep 29, 2025See slack thread: [Link Removed] Resume : In the context of the object substitution for Revit, when TM starts, it exports a csv listing the available objects and their corresponding thumbnail. This ...
UAssetManager::ChangeBundleStateForPrimaryAssets: Performance: Avoid canceling loads in progress when new bundles added and the in progress bundles are kept
UE - Foundation - Data Pipeline - Cooker - Mar 4, 2024UAssetManager::ChangeBundleStateForPrimaryAssets allows adding new BundleNames to the list of BundleNames loaded for a PrimaryAssetId. Each BundleName specifies a BundleEntry with a list of assets. ...
Major performance drop with instanced meshes since PhysX 3.4 upgrade
UE - Simulation - Physics - Mar 15, 2017Major performance drop with instanced meshes since PhysX 3.4 upgrade Regression: YES Worked: 3172292 (4.13.2) Broken: 3249277 (4.14.3) For me, my results were: 4.8 through 4.13 No Collision - ...
Editor performance drops when locking read-only levels.
Tools - Sep 2, 2015When locking read-only levels (via Levels->context menu), each frame we check that both the package exists on disk and whether the file is read-only. Performing this each tick can cause a substantia ...
Editor crashes when a hot reload is performed on a project that contains a custom User Defined Struct code class
UE - Foundation - Core - Feb 20, 2017Adding a custom User Defined Struct code class to a project causes the Editor to crash whenever a hot reload is performed on that project. Removing the custom User Defined Struct class allows hot re ...
Performance Drop Occurring During PIE When Blueprint is Open
UE - Gameplay - Blueprint - May 20, 2016Having a blueprint open during PIE causes a significant drop in performance. Having multiple blueprints open can almost render more complicated projects unplayable. The user has reported 120 fps wi ...
BuildId in the UE4Editor.version file for a local binary build will sometimes be updated when a hot reload is performed
UE - Foundation - Core - Feb 10, 2018Performing a hot reload on a project that is using a local binary build of the Engine will sometimes result in the Engine's UE4Editor.version file being updated with a new BuildId value. That result ...
A newly added BlueprintImplementableEvent no longer appears in the context search menu of an Event Graph if a Hot Recompile was performed after the event was added in code.
UE - Gameplay - Blueprint - Dec 19, 2014Performing a Hot Recompile in the Editor after adding a BlueprintImplementableEvent to code class does not have the new event added to the right-click context search window in the Event Graph of a B ...
Performing a Hot Reload after changing a UPROPERTY from BlueprintReadWrite to BlueprintReadOnly results in the variable not being shown in context sensitive search results in the Event Graph.
UE - Gameplay - Blueprint - Mar 3, 2015Changing a UPROPERTY value from BlueprintReadWrite to BlueprintReadOnly, or vice versa, and performing a Hot Reload results in the variables not being found in the Blueprint's Event Graph context se ...
Huge performance hit when recording a demo (demorec)
UE - Networking - Jun 3, 2019The current engine version (4.22) seems to suffer a huge performance hit when using the demo recording (demorec) feature. This issue is present in both the editor and the packaged game (developer bu ...