<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<meta name="Generator" content="Microsoft Word 15 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman",serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:#0563C1;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:#954F72;
text-decoration:underline;}
p.msonormal0, li.msonormal0, div.msonormal0
{mso-style-name:msonormal;
margin:0cm;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman",serif;}
span.EmailStyle19
{mso-style-type:personal-reply;
font-family:"Calibri",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-US" link="#0563C1" vlink="#954F72">
<div class="WordSection1">
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">We’ve tried alpha shapes option of vtkDelanay3D several times but it always failed on our data.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">If you need flat brain surface without furrows, one option is to convert your mesh to image and apply morphological opening with 10mm kernel size. If you want to play with
this without coding then you can use 3D Slicer’s Segmentation module (import your mesh in Segmentations module, select Smoothing effect in Segment editor module, choose Closing (fill holes) effect and set 10mm for kernel size).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Andras<o:p></o:p></span></p>
<p class="MsoNormal"><a name="_MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></a></p>
<span style="mso-bookmark:_MailEndCompose"></span>
<div>
<div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm">
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> vtkusers [mailto:vtkusers-bounces@vtk.org]
<b>On Behalf Of </b>M. Jordan<br>
<b>Sent:</b> December 9, 2016 7:20<br>
<b>To:</b> vtkusers@vtk.org<br>
<b>Subject:</b> [vtkusers] Compute Concave Hull in VTK<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div id="divtagdefaultwrapper">
<p><span style="font-family:"Calibri",sans-serif;color:black">Hi,<br>
<br>
i would like to compute the concave (not convex!) hull of a vtk polydata surface.<br>
I have a brain model and would like to get a flat surface without furrows.<br>
<br>
I tried vtkDelaunay3D with some values for alpha and subsequently a geometry filter to get the surface, but
<br>
the result is not that good. (the surface isn't closed and i think that there are some triangles inside the surface).<o:p></o:p></span></p>
<p><span style="font-family:"Calibri",sans-serif;color:black"><br>
Is there another method to compute the concave hull?<br>
<br>
Thank you!<o:p></o:p></span></p>
<p><span style="font-family:"Calibri",sans-serif;color:black"><o:p> </o:p></span></p>
<p style="margin-bottom:12.0pt"><span style="font-family:"Calibri",sans-serif;color:black"><o:p> </o:p></span></p>
</div>
</div>
</body>
</html>