<blockquote class="gmail_quote" style="margin: 0;margin-left: 0.8ex;border-left: 1px #ccc solid;padding-left: 1ex;"><p>Hi Simon,</p></blockquote><div><br></div><div>You should use BSplines for this.</div><div><br></div><div>Regards,</div><div><br></div><div>Dave</div>