You can use Delaunay triangulation (vtkDelaunay2D or vtkDelaunay3D). But keep in mind that this algorithm only returns the convex hull of a point cloud. I just remembered that there is also another algorithm called Quick Hull (google search for QHull). This algorithm also returns a convex hull. I'm not sure if there is an algorithm that can actually handle both convex and concave hulls (as far as I know getting a concave hull is a much more difficult task than a convex hull).
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<div><span class="gmail_quote">On 9/18/07, <b class="gmail_sendername">Paulo Bernardes</b> <<a href="mailto:pbernardes@uaum.uminho.pt">pbernardes@uaum.uminho.pt</a>> wrote:</span>
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<p><font face="Arial" size="2"><span style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Dear all,</span></font></p>
<p><font face="Arial" size="2"><span style="FONT-SIZE: 10pt; FONT-FAMILY: Arial"> </span></font></p>
<p><font face="Arial" size="2"><span lang="EN-GB" style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Is there any way to determine the outer polygon of an arbitrary point cloud using VTK?</span></font></p>
<p><font face="Arial" size="2"><span lang="EN-GB" style="FONT-SIZE: 10pt; FONT-FAMILY: Arial"> </span></font></p>
<p><font face="Arial" size="2"><span lang="EN-GB" style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Many Thanks</span></font></p>
<p><font face="Arial" size="2"><span lang="EN-GB" style="FONT-SIZE: 10pt; FONT-FAMILY: Arial"> </span></font></p>
<p><font face="Arial" size="2"><span lang="EN-GB" style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Paulo</span></font></p>
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