Unable to create a blueprint containing multiple actors

Question

I'm having some trouble in Unreal 4.23. According to the documentation, if I select a bunch of Actors and hit the Blueprints button in the toolbar, I should get an option to "Convert Selection To Blueprint Class," which then gives me a choice of three options of what to do with the different objects before creating the blueprint. Instead, I get "Convert Selected Components To Blueprint Class," the dialog asking me what to do with the objects does not show up -- it goes straight to the one asking where to save the blueprint -- and the blueprint it generates is a mess: textures get changed, the names of the actors are lost, and all of the objects are "dropped on the ground" rather than being positioned where they had been relative to each other!

The objects in question are a character (Skeletal Mesh) and several sub-objects representing the character's clothing (also skeletal meshes, attached to the character as sub-objects in the World Outliner hierarchy.) I basically want to do the same thing you can do in Unity: take this character and save it as a prefab so I can make copies of it easily in different maps. From researching the documentation and various forum posts, it seems like making them into a Blueprint using the Harvest Components option is the best way to do that, but that option is never showing up! This problem persists even after closing and restarting Unreal.

Anyone have any idea why the editor is not behaving as documented, and what I can do about it?

(And yes, I know about Prefabricator. This is supposed to be for Marketplace content, though, where third-party dependencies are discouraged.)

Answer 1

You cannot create a Blueprint that holds multiple actors in the same way the level does in World Outliner. Unreal is different than Unity in that the hierarchy stuff in the level is not the same as the hierarchy stuff within an Actor. Blueprints are (usually) subclasses of the C++ classes UObject, AActor, or UComponent. An Actor has a set of Components, which have an offset if they are subclass of USceneComponent. What the editor is trying to do here is combine all the components of each Actor in the selection into one Actor, and it appears something in the process is failing. There are quite a few edge cases not handled by this process, especially in 4.23.

You can use a SubActor component to get MOST of what you are talking about here; from what I recall, it's basically a nicely-pieced-together setup that does Actor::AttachToComponent for you.

I recommend changing all your clothing actors into skeletal mesh components that are all applied to your character, but default to invisible.

If you just want to manually copy it into different maps, selecting then right-click copy/paste in World Outliner might work.