I was trying to create my own custom volume from AVolume parent class, and make it Blueprintable.
But it dosen’t work. I encounter several problem:
First, CheckForErrors function from AVolume check if collision bounds radius if >0, but in blueprint viewport, there is no brush, so it report an error, and we cant compile/save the blueprint.
I have overrided the CheckForErrors to not have this error anymore, and it work fine in blueprint editor.
Second, when spawning the blueprint in the viewport, it wont show the brush. Because the actor is spawned in the world using UActorFactoryBlueprint, but the creation of the brush is done in UActorFactoryBoxVolume.
Hope this informations will help you
It seems it has been reported and backlogged in issue UE-47978. Hoping it will be fixed some day 