I’m interested to see how it goes, I’ve been meaning to look into how TOctree can be used for ages. Will help with any questions you have if I can.
Can I suggest putting it up on Github as a public repo? Makes sharing a lot easier than with just a source download.
One thing from a very quick look at your code - your FQuadrantOctreeElement struct should contain a pointer to an AActor, rather than embed an AActor directly.