[quote user="Jon Summers"]
However, in order to visualise what is going on, it can be useful to create a real B-Spline curve that you can see and manipulate.
[/quote]
Right, so I just converted the element to a b-spline curve and amended the select case statement to cater for the B-spline curve element type. The debug values for tangent and u are precisely the same as for the complex chain.