The xxx.generated.h is used for files/classes that derive from UObject. It’s part of making all those crazy macros like (GENERATED_BODY() work. It’s also part of their precomputed header system. If you use the class wizard and derive from “None” instead, you don’t need it (and still able to use FVector). However, instead of using a class wizard to create a header file that will only have enums and structs that don’t interact with Unreal’s systems, you can just create a text file in the same folder as the files that will include it.