<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>
<!-- Template generated by Exclaimer Mail Disclaimers on 03:32:13 Monday, 30 April 2018 -->
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="Generator" content="Microsoft Word 12 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:"MS Mincho";
panose-1:2 2 6 9 4 2 5 8 3 4;}
@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;}
@font-face
{font-family:"\@MS Mincho";
panose-1:2 2 6 9 4 2 5 8 3 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph
{mso-style-priority:34;
margin-top:0in;
margin-right:0in;
margin-bottom:0in;
margin-left:.5in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
/* List Definitions */
@list l0
{mso-list-id:911430709;
mso-list-type:hybrid;
mso-list-template-ids:-243787164 134807567 134807577 134807579 134807567 134807577 134807579 134807567 134807577 134807579;}
@list l0:level1
{mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;}
ol
{margin-bottom:0in;}
ul
{margin-bottom:0in;}
--></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-GB" link="blue" vlink="purple">
<p></p>
<div class="WordSection1">
<p class="MsoNormal"><span lang="EN-US">Hello,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I have the following challenge at the moment: I’m reconstructing an unstructured grid that consists only of hexahedra, given only the vertex and edge connectivity information.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">So far, by enumerating all 4-cycles emanating from each vertex, I have successfully identified all quad faces. But I’m struggling a bit with the next step: given all the faces (and their edges), how to quickly identify
all hexahedral cells? Currently I have implemented the following brute-force approach:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span lang="EN-US"><span style="mso-list:Ignore">1.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US">For each face F, find all faces that share one edge with the face (typically ~12 adjacent faces are found)<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span lang="EN-US"><span style="mso-list:Ignore">2.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US">Enumerate all combinations of four faces in this list of adjacent faces ( 12-take-4, about 500 combinations)<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span lang="EN-US"><span style="mso-list:Ignore">3.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US">Select the 4-tuples of faces that have exactly 12 unique edges (typically ~8 combinations left)<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span lang="EN-US"><span style="mso-list:Ignore">4.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US">From these ~8, select the ones that can be capped by the original face (F) (this is given by the step 1) and an existing other face.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Like I said this is brute-force approach (that does work). Are there smarter ways to accomplish the given challenge?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Thanks and best wishes,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Menno Deij – van Rijswijk<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
</div>
<br>
<font style="font-family:Verdana;font-size:8pt;color:#7D7D7D;font-weight:bold;">dr. ir.</font><font style="font-family:Verdana;font-size:8pt;color:#7D7D7D;font-weight:bold;">
</font><font style="font-family: Verdana;font-size:8pt;color:#7D7D7D;font-weight:bold;">Menno A.</font><font style="font-family: Verdana;font-size:8pt;color:#7D7D7D;font-weight:bold;">
</font><font style="font-family:Verdana;font-size:8pt;color:#7D7D7D;font-weight:bold;">Deij-van Rijswijk</font><font size="3" face="Segoe UI"></font><font style="font-family:Verdana;font-size:8pt;color:#7D7D7D;font-weight:bold;"> |
</font><font style="font-family:Verdana;font-size:8pt;color:#7D7D7D;font-weight:bold;">Researcher / Software Engineer</font><font style="font-family:Verdana;font-size:8pt;color:#7D7D7D;font-weight:bold;"> |
</font><font style="font-family:Verdana;font-size:8pt;color:#7D7D7D;font-weight:bold;">MARIN Software Group</font><br>
<font style="font-family:Verdana;font-size:9pt;color:#7D7D7D;font-weight:bold;">MARIN</font><font style="font-family:Verdana;font-size:8pt;color:#7D7D7D;"> | T
</font><font style="font-family:Verdana;font-size:8pt;color:#7D7D7D;">+31 317 49 35 06</font><font color="#7d7d7d" size="2" face="Segoe UI"></font><font style="font-family:Verdana;font-size:8pt;"> |
</font><span style="font-family:Verdana;font-size:8pt;"><a href="mailto:M.Deij@marin.nl" title="" target="" style="font-family:Verdana;font-size:8pt;"><span style="font-family:Verdana; font-size:8pt;">M.Deij@marin.nl</span></a></span><font color="#7d7d7d" size="2" face="Segoe UI"></font><font style="font-family:Verdana;font-size:8pt;"> |
</font><span style="font-family:Verdana;font-size:8pt;"><a href="http://www.marin.nl" title="" target="" style="font-family:Verdana;font-size:8pt;"><span style="font-family:Verdana; font-size:8pt;">www.marin.nl</span></a></span><br>
<br>
<a href="https://www.linkedin.com/company/marin" target=""><img width="16" height="16" style="border: 0px Solid ; " src="cid:imagef37852.PNG@a4af76ac.46ac5448" alt="LinkedIn"></a> <a href="http://www.youtube.com/marinmultimedia" target=""><img width="16" height="16" style="border: 0px Solid ; " src="cid:imageacc9c3.PNG@d1551db9.479aef8e" alt="YouTube"></a> <a href="https://twitter.com/MARIN_nieuws" target=""><img width="16" height="16" style="border: 0px Solid ; " src="cid:imagea88c6f.PNG@1522e809.42a6ebf6" alt="Twitter"></a> <a href="https://www.facebook.com/marin.wageningen" target=""><img width="16" height="16" style="border: 0px Solid ; " src="cid:image974b23.PNG@b6dcea81.458657a2" alt="Facebook"></a><br>
<font style="FONT-FAMILY: Verdana; FONT-SIZE: 8pt" color="#7d7d7d" size="2" face="Verdana">MARIN news:
<font style="font-family:Verdana;font-size:8pt;"><span style="font-family:Verdana;font-size:8pt;"><a href="http://www.marin.nl/web/News/News-items/Wave-resistance-minimisation-in-practical-ship-design-1.htm" title="" target="" style="font-family:Verdana;font-size:8pt;"><span style="font-family:Verdana; font-size:8pt;">Wave
resistance minimisation in practical ship design</span></a></span></font></font>
<p></p>
<p></EXCLAIMER:ORIGINAL_BODY_AFTER></p>
</EXCLAIMER:TEXT_ONLY></EXCLAIMER:AD></EXCLAIMER:AD>
</body>
</html>