[Closed] Distance constraint maxscript

Hi, Im very new with maxscript and Im trying to make a tentacle using spring controllers, I have some part of the script working, but what I cant get is some way to limit the distance between the points so the tentacle doesnt change its lenght, the scripts working on the selected objects, so if you have a line o helpers selected you run the script and create the bones between the points. Is there any way to get a distance constraint?

fn creaHuesoEntreSelecciones ancho alto tapersito MassStrenght DragStrenght Tension Dampening =
	
(
	bns=#()
	pts = selection as array

	for i = 1 to pts.count-1 do
	(
		crearHuesos= bonesys.createbone (pts[i].pos) (pts[i+1].pos) [0,0,1]	
		crearHuesos.name = ("huesito_"+i as string)
	)


	creaHuesoFinal=bonesys.createbone (pts[pts.count].pos) (pts[pts.count].pos) [0,0,1]
	creaHuesoFinal.length=5
	creaHuesoFinal.name= ("huesito_"+pts.count as string)

	--AÑADE LOS HUESOS A BNS COMO ARRAY
	bns = $huesito_* as array
	--AÑADE LOS HUESOS A PTS COMO ARRAY
	pts= selection as array
	
	bns.width= ancho
	bns.Height= alto
	bns.taper= tapersito

--CREA LOS POSITION CONSTRAINT Y LOS LOOK AT CONSTRAINT A LOS HUESOS
	for i = 1 to bns.count do
	(
		if bns[i] != bns[1] then bns[i].parent = bns[i-1]
		bns[i].position.controller =position_constraint()
		bns[i].position.controller.appendtarget pts[i] 100
		bns[i].rotation.controller =lookAt_constraint target_axis:0 upnode_axis:2 StoUP_axis:2 lookat_vector_length:0
		if bns[i] != bns[bns.count] then bns[i].rotation.controller.appendtarget pts[i+1] 100 else 0
		bns[i].rotation.controller.pickupnode=pts[i]
		bns[i].rotation.controller.upnode_world=false
	--  	bns[i].boneScaleType = #scale
	-- 	print pts[i].pos
			
	)

	--CREA LOS POSITION SPRING CONTROLERS A LOS PUNTOS
	for i= 1 to pts.count do
	(
		if pts[i] != pts[1] then pts[i].parent = pts[i-1]
		ctrlSpring= pts[i].pos.controller=  SpringPositionController()
		ctrlSpring.setMass MassStrenght
		ctrlSpring.setDrag  DragStrenght
		ctrlSpring.setTension 1 Tension 
		ctrlSpring.setDampening 1 Dampening 
	)
	
	select bns

)

rollout CreaCadenaEntreSelecciones "CreateBones"
(
	 
	group "bone Properties"(
	spinner UI_width "width" range:[1,100,2]
	spinner UI_height "height"range:[1,100,2]
	spinner UI_taper "taper" range:[1,100,2]
	)
	group "spring Properties"(
	spinner UI_Mass "mass" range:[1,2000,300]
	spinner UI_Drag "drag" range:[1,10,1]
	spinner UI_Tension "Tension" range:[1,9999,2]
	spinner UI_Dampening "dampening" range:[0.1,100,0.5]
	)
	
	button CreateBones "CreateBones"
	
	on CreateBones pressed do
	(
		creaHuesoEntreSelecciones (UI_width.value)  (UI_height.value)  (UI_taper.value) (UI_Mass.value) (UI_Drag.value) (UI_Tension.value) (UI_Dampening.value)
	)
	
)


createDialog CreaCadenaEntreSelecciones