position_of_Area_Godot

# SpaceCell.gd
extends Area

var contacts = {}
var force = Vector3(0,0,0)			# the force that acts on the cell
var velocity = Vector3(0,0,0)		# the velocity of the cell

const FORCE_K = 1				    # the constant k in F=kx between the cells
const REST_DISTANCE = 1	            # the distance between two cells at which the cells are at rest

func update_force():
	# updates the force that acts on a cell i from all other cells j
#	var pos_i = get_pos()												# <------- THE PROBLEM
#	var pos_i = position												# <------- THE PROBLEM
	var pos_i = self.position							                # <------- THE PROBLEM
	for cell_j in contacts:
		var pos_j = cell_j.position										# <------- THE PROBLEM
		var x = pos_i - pos_j
		var x0 = x.normalized()*REST_DISTANCE
		var force_ij = FORCE_K*(x - x0)
		force += force_ij

func update_velocity(delta):
	velocity += force * delta

func update_position(delta):
	self.position = self.position + velocity*delta

func _physics_process(delta):
	update_force()
	update_velocity(delta)
	update_position(delta)

func area_entered(area):
	contacts[area.cellname] = area

func area_exited(area):
	contacts.erase(area.cellname)


# ERROR OUTPUT:
# Invalid get index 'position' (on base: 'Area (SpaceCell.gd)').

# SpaceCell SCENE SETUP:
# SpaceCell	[Area]							<----- Script attached called SpaceCell.gd, see above
# ---- CollisionShape (shaped like sphere)
# ---- ---- CSGMesh (shaped like sphere)