Completely missed what you were asking. I guess you could store a map of your point coordinates and then do a look up...<br><br>Anja<br><br><div><span class="gmail_quote">On 29/09/06, <b class="gmail_sendername">Anja Ende</b>
 &lt;<a href="mailto:anja.ende@googlemail.com">anja.ende@googlemail.com</a>&gt; wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hi,<br><br>Use vtkPoints::GetNumberOfPoints() to check this.<br><br>so, <br><br>if (myPointCollection-&gt;GetNumberOfPoints() == 0)<br>&nbsp;&nbsp;&nbsp; myPointCollection-&gt;InsertPoint(.....)<br><br>Cheers,<br><span class="sg">Anja<br>


</span></blockquote></div><br>