UObject

• ClassPrivate Is the UClass of the object instance. The thing you get back when you call GetClass().
• If a object was loaded from “a loader” (FAsyncPackage or LoadPackageInternal) it will have the RF_WasLoaded flag. This can be very useful to use on actors to know if they got loaded from disk or spawned at runtime.
• UObject Construction & Post Initalization

Reflection

Since 5.5 TObjectPtr<> is mandatory for UObject variables (only for members of classes and structs). You still need to mark the variable with UPROPERTY() or the UObject ref will never be cleared.

See

• Reflection System
• Garbage Collection

There is also AddReferencedObjects, for example this is used in AActor to add all owned components. (For UObjects only, otherwise look for AddReferencedObjectsGlobals) The GC will call this as much as it needs (TStrongObjectPtr would be better performance wise in some cases).

To use TStrongObjectPtr you must include the type

Archetype

GetArchetype gives you the template object that was used. For example, the UObject you get from a BP editor sub object editor (with BlueprintEditor->GetSubobjectEditor()->GetDragDropTree()->GetSelectedItems()) is the same than the returned archetype of the component that lives in the preview world.

GEN_VARIABLE

These objects are templates, meaning they aren’t owned by an actor component instance but by the supposed owning actor class (get it by using GetTypedOuter<UClass>())

Virtual functions details

• Actor Load/Init Function Cheatsheet

• PostTransacted is called when you move/edit anything in a BP

• When you compile a BP, PostInitProperties, PostEditChangeProperty and PostCDOContruct are called.

• When you edit a property PostEditChangeProperty is called (Doesn’t work for Transforms)

• PostCDOContruct always has its World null.

TStrongObjectPtr

Use MyStrPtr.Reset(SomeObject) to set it.