i've created the "Plugin" folder with this plugin, in the project's one, but can you please give a little guide on how its intended to be included into the Solution?

All publicly accessible classes should be marked with KDTREE_API to mark their methods as EXTERN and prevent other modules from attempting to link against them statically.

e.g. the UkdtreeBPLibrary should be declared:
class KDTREE_API UKdtreeBPLibrary

This will fix "unresolved external symbol" linker errors when attempting to call those functions directly from C++ in another module.

These errors have not been observed in the past because the module is designed to be called from non-nativized blueprint, which only links dynamically, never statically. However, these issues may start to appear if calling blueprints are added to the nativization list!

Hello,
I would like to store meta data about positions in a game. How would I go about returning the results as an index of the original array? Or what would you recommend going about storing meta data for a particular position in an efficient manner?
Thanks,
Dan

KdtreeBPLibrary.cpp, Line 29:
Data.Add(Tree.Internal.Data[Index]);
will return only the first n vertices from the vertex buffer, not the matched vertices from the search.
The line should be:
Data.Add(Tree.Internal.Data[Indices[Index]]);