In my case this is an rts doing drag select, and i have a C++ PlayerCameraManager class: TestPlayerCameraManager. From it you can call GetViewFrustumBounds() and get a FConvexVolume. From that I assume you do an overlap test, since convex overlap is a supported thing.
Edit: I just read this.
Edit: I actually got drag select fully implemented !!!
So I built a FConvexVolume representing the dragged area on the viewport. Its just some deproject calls, then building some planes. Did take me like 8 hrs to get it working though …
DragSelectExample.cpp (3.2 KB)