Does exist a lib to simulate magnet ?

thanks,

But with physics i have done the folliwing code but without success.

Graphics3D 640,400,16,2
SetBuffer BackBuffer()

Global camera=CreateCamera()

Global plane=CreatePlane()
EntityColor plane,50,50,200

Global light=CreateLight()
RotateEntity light,90,0,0

Global pivot=CreatePivot()
PositionEntity pivot ,0,0,0

;=======PhysX=====================
pxCreateWorld(0,"key")					
pxSetGravity(0,-9.81,0)
;=================================

; Create cube
n=0
For l = 1 To 3
	For a# = 1 To 360 Step 20	
		CreateNeoDym( Cos(a#)*10, n, Sin(a#)*10, 0 )
		n = n +1	
	Next 	
Next 

PositionEntity camera, 0,10,-120

While Not KeyDown( 1 )
	UpdateNeoDym()
	RenderWorld
    pxRenderPhysic(30,0)
	Flip
Wend

pxDestroyWorld()
End

Type TNeoDym_Magnet
	Field Px
	Field mesh%
End Type 

Function CreateNeoDym( pX, pY, pZ, pPivot=0 )
	Local l.TNeoDym_Magnet = New TNeoDym_Magnet
	If pPivot > 0 Then 
		l\mesh = CreateSphere(8,pPivot)
	Else
		l\mesh = CreateSphere(8)
	EndIf
 
    l\pX=pxCreateMagnet(1, 50, 100)
    pxMagnetSetMaxRadius( l\pX, 200)
    pxMagnetSetMinRadius( l\pX, 205)
	pxMagnetSetPosition(l\pX,pX, pY, pZ)       
    pxMagnetActivate(l\pX, 1, 1)
	PositionEntity l\mesh, pX, pY, pZ	
	Return Handle( l )
End Function 


Function UpdateNeoDym( )
	For l.TNeoDym_Magnet = Each TNeoDym_Magnet
		PositionEntity l\mesh, pxMagnetGetPositionX( l\pX),pxMagnetGetPositionY( l\pX),pxMagnetGetPositionZ( l\pX)
	Next
End Function