Install with:
go get github.com/lkolbly/go-octree/octree

Import with:
import "github.com/lkolbly/go-octree/octree"

It doesn't implement much, yet. You can make an octree:
ot := octree.NewOctree()

You can add a point to it:
x := 0.5
y := 0.5
z := 0.5
ot.Add(MyDataStructure{}, x, y, z)

You can find the nearest point:
sv, dist := ot.FindNearest(x,y,z)