How can I generate a working NavigationMesh from code?

[system]

	Attention	Topic was automatically imported from the old Question2Answer platform.
	Asked By	Reisflocke

Hello there!

I’m currently trying to implement path finding for my AI in my 3D Topw Down Game.
I created a custom level editor and now I wanne auto generate a working NavigationMesh.

My currnet approach (this code runs in the Editor via tool Script):

#SETUP (done in other parts of the script)
var floor_positions = [Vector2(1,3), Vector2(0, 4)] # and so on ...
var nav_mesh: ArrayMesh = load("something/something/nav_mesh.obj")

func create_node(node_new: Node, parent: Node=self) -> Node:
	parent.add_child(node_new)
	node_new.set_owner(get_tree().edited_scene_root)
	return node_new

#**GENERATION (the nav mesh generation part)**
		#generate nav mesh
	var st := SurfaceTool.new()
	for p in floor_positions:
			var mesh_transform: Transform = Transform(Basis(), Vector3(p.x, 0.0, p.y))
			st.append_from(nav_mesh, 0, mesh_transform)
	var navigation: Navigation = create_node(Navigation.new())
	navigation.hide()
	var navigation_mesh_inst: NavigationMeshInstance = create_node(NavigationMeshInstance.new(), navigation)
	navigation_mesh_inst.navmesh = NavigationMesh.new()
	navigation_mesh_inst.navmesh.create_from_mesh(st.commit())

This code DOES generate a NavigationMesh, but once I try to test it with:
get_simple_path()
it returns:
What is the reason for this?

PS: if you need any more details on this complex question I’m happy to provide them

[system]

	Reply From:	doggod

var targetPos = target.global_transform.origin
begin = nav.get_closest_point(self.get_translation())
end = nav.get_closest_point(target.get_translation())
if begin == end or begin.distance_to(end) < 1.5 or end == PreviousDest:
	target = targets[rand_range(0, targets.size() -1)]
	begin = nav.get_closest_point(self.get_translation())
	end = nav.get_closest_point(target.get_translation())
var p = nav.get_simple_path(begin, end)
path = Array(p)
path.invert()

ps:get_simple_path are local coordinates, and the point must be on the navigation grid