<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div>Hello Gustavo,</div><div><br></div><div style="color: rgb(0, 0, 0); font-size: 16px; background-color: transparent; font-style: normal; font-family: 'times new roman', 'new york', times, serif; ">I've attached a ".<span id="misspell-0" class="mark">geo</span>" that <span id="misspell-1" class="mark">i'm</span> <span id="misspell-2" class=""><span>currently</span></span> using for <span id="misspell-3" class="mark">PBCs</span>. If you want a structured mesh on the cube faces you have to <span id="misspell-4" class="mark">uncomment</span> the Transfinite Surface lines. You are right, the points aren't exactly the same, you can see a difference after 10-6, which is not so bad... If you <span id="misspell-5" class=""><span>really</span></span> need a perfect match you can copy the points by your self in your program, it's true,
it becomes a little complicated but not impossible. </div><div style="color: rgb(0, 0, 0); font-size: 16px; background-color: transparent; font-style: normal; font-family: 'times new roman', 'new york', times, serif; "><br></div><div style="color: rgb(0, 0, 0); font-size: 16px; background-color: transparent; font-style: normal; font-family: 'times new roman', 'new york', times, serif; ">Hope that helps,</div><div style="color: rgb(0, 0, 0); font-size: 16px; background-color: transparent; font-style: normal; font-family: 'times new roman', 'new york', times, serif; "><br></div><div style="color: rgb(0, 0, 0); font-size: 16px; background-color: transparent; font-style: normal; font-family: 'times new roman', 'new york', times, serif; ">Dorin</div><div><br></div> <div style="font-size: 12pt; font-family: 'times new roman', 'new york', times, serif; "> <div style="font-size: 12pt; font-family: 'times new roman', 'new york', times, serif; "> <div
dir="ltr"> <hr size="1"> <font size="2" face="Arial"> <b><span style="font-weight:bold;">From:</span></b> Gustavo Charles Peixoto de Oliveira <tavolesliv@gmail.com><br> <b><span style="font-weight: bold;">To:</span></b> niculescu_dorin85@yahoo.com <br><b><span style="font-weight: bold;">Cc:</span></b> gmsh@geuz.org; felipe.alves.portela@gmail.com <br> <b><span style="font-weight: bold;">Sent:</span></b> Monday, 15 April 2013, 19:02<br> <b><span style="font-weight: bold;">Subject:</span></b> 3D Periodic Boundary Conditions with test.<br> </font> </div> <div class="y_msg_container"><br>
<div id="yiv893190064"><div dir="ltr"><div><div><div><div>Dear all, <br><br></div>I've read your discussion about 3D <span id="misspell-10" class="mark">PBC</span> here <br><br>http://www.geuz.org/pipermail/gmsh/2013/008054.html<br>
<br></div>and I'd like to give some contribution. I'm a GMSH newbie and my need seems similar to yours. <br><br></div>I've been trying to generate 3D <span id="misspell-12" class="mark">PBC</span> meshes for simple geometries like square, triangular and rectangular channels with the Periodic Surface command by using the version 2.7.0. However, before running my code, I had to write a function to verify if the periodicity really was being satisfied like Dorin did. It's surprisingly that the test fails for 1 point for some refined meshes. However, it succeeds for coarser meshes of the same kind. I didn't know why...<br>
<br>For instance, my script test outputs something like that for an x-extrusion:<br><br>Warning! Left and right y-components are not equal. <br>Entry: 72<br><span id="misspell-14" class="mark">yU</span> = 0.5; <span id="misspell-15" class="mark">yV</span> = 0.625<br>Warning! Left and right z-components are not equal. <br>
Entry: 72<br><span id="misspell-16" class="mark">zU</span> = 0.25; <span id="misspell-17" class="mark">zV</span> = 0.625<br><br></div><div>As you can see, the y-coordinate is "slightly" different, whereas z-component is a bit more. In the end, both differs, but for an unique point! Although the error is small, it is problematic for my purposes.<br>
<br></div><div>I didn't test the output with Transfinite option. <br><br>Dorin, I will test your suggestion to use Extrude + Transfinite, but have you already found some solution concerning extrusion for further directions?<br>
<br></div><div>Would be this case a bug of the Periodic Surface function? <br></div><div><br></div><div>Kind regards,<br></div><div><div><div><div><div><br>-- <br><div dir="ltr">Gustavo Oliveira, <span id="misspell-20" class="mark">Ph</span>.D. Student<br>Graduate Program in Mechanical Engineering<br>
State University of Rio de <span id="misspell-22" class="mark">Janeiro</span><div><br><br></div></div>
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