Hi! I have a strange problem. When I create an object of type USkeletalMeshComponent via CreateDefaultSubobject and spawn it everything works correctly. It is displayed. But through NewObject(this) it doesn’t work. It is not displayed. CreateDefaultSubobject I write in the constructor, NewObject outside the constructor. After creating an instance in both cases, I do only one thing - set the Mesh. I have it from another object. There is probably a difference between these two ways of creating an object, other than the obvious ones. What am I missing?
The problem is that the component needs to be registered with NewObject. I don’t know if this applies to everything, but for UScene the Component should be registered
CreateDefaultSubobject is the way to add components in the constructor. The most obvious benefit to this is that the components will be editable in the editor and blueprint-derived classes. There are downsides to this, such as not being able to drive the component spawning via variables. Afaik it has to do with the way how objects are spawned in Unreal (the gist of it from what I can tell is that the “ClassDefaultObject” is created based on C++ constructor and newly spawned actors are copies of the CDO rather than newly created). Blueprint constructors work differently and are more flexible, i.e allow editing on per-instance basis.
NewObject is the way to handle spawning during runtime i.e gameplay, and yes, they need to be registered. If you want to dynamically spawn components in the editor via C++ instead of Blueprint, you’d need to do so with i.e PostEditChangeProperty and such functions, as well as get yourself accustomed to property specifiers like transients and look up which flags are set in the SpawnActor function to know what also to add so editor functions like Undo would work as expected.
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Thanks for the explanation!