<div dir="ltr"><div>Thank you for your response. But that is quite unexpected, since the normal vectors define the volume. So my question is, how can I make all the normal vectors point outward the volume? I am working with boundary element method and the normal vector orientation is really important to the method.</div><div><br></div><div>Thanks in advance,<br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, May 17, 2018 at 3:54 AM, Christophe Geuzaine <span dir="ltr"><<a href="mailto:geuzaine@gmail.com" target="_blank">geuzaine@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class=""><br>
<br>
> On 16 May 2018, at 00:28, Anderson Gabriel Santiago <<a href="mailto:agasantiago.usp@gmail.com">agasantiago.usp@gmail.com</a>> wrote:<br>
> <br>
> Dear all,<br>
> <br>
> I am using GMSH to create a 3D surface mesh. For some unknown reason, some normal vectors points inwards, not outwards,<br>
<br>
</span>The mesh is oriented according to the orientation of the geometrical surface - everything is correct in your file. You can check by visualizing both the geometry and the mesh normals (in Tools->Options->Geometry or Mesh->Visibility->Normals)<br>
<br>
Christophe<br>
<div><div class="h5"><br>
<br>
> as I would expect, since I defined a solid limited by plane surfaces.<br>
> <br>
> Here is the GEO file I created using the GMSH GUI.<br>
> <br>
> <br>
> // Gmsh project created on Tue May 15 19:19:43 2018<br>
> SetFactory("OpenCASCADE");<br>
> //+<br>
> Point(1) = {0, 0, 0, 1.0};<br>
> //+<br>
> Point(2) = {1, 0, 0, 1.0};<br>
> //+<br>
> Point(3) = {1, 1, 0, 1.0};<br>
> //+<br>
> Point(4) = {0, 1, 0, 1.0};<br>
> //+<br>
> Point(5) = {0, 0, 1, 1.0};<br>
> //+<br>
> Point(6) = {1, 0, 1, 1.0};<br>
> //+<br>
> Point(7) = {1, 1, 1, 1.0};<br>
> //+<br>
> Point(8) = {0, 1, 1, 1.0};<br>
> //+<br>
> Line(1) = {1, 2};<br>
> //+<br>
> Line(2) = {2, 6};<br>
> //+<br>
> Line(3) = {6, 5};<br>
> //+<br>
> Line(4) = {5, 1};<br>
> //+<br>
> Line(5) = {5, 8};<br>
> //+<br>
> Line(6) = {8, 4};<br>
> //+<br>
> Line(7) = {4, 1};<br>
> //+<br>
> Line(8) = {8, 7};<br>
> //+<br>
> Line(9) = {7, 3};<br>
> //+<br>
> Line(10) = {3, 4};<br>
> //+<br>
> Line(11) = {6, 7};<br>
> //+<br>
> Line(12) = {3, 2};<br>
> //+<br>
> Line Loop(1) = {4, -7, -6, -5};<br>
> //+<br>
> Plane Surface(1) = {1};<br>
> //+<br>
> Line Loop(2) = {2, 11, 9, 12};<br>
> //+<br>
> Plane Surface(2) = {2};<br>
> //+<br>
> Line Loop(3) = {3, 5, 8, -11};<br>
> //+<br>
> Plane Surface(3) = {3};<br>
> //+<br>
> Line Loop(4) = {10, 7, 1, -12};<br>
> //+<br>
> Plane Surface(4) = {4};<br>
> //+<br>
> Line Loop(5) = {9, 10, -6, 8};<br>
> //+<br>
> Plane Surface(5) = {5};<br>
> //+<br>
> Line Loop(6) = {3, 4, 1, 2};<br>
> //+<br>
> Plane Surface(6) = {6};<br>
> //+<br>
> Surface Loop(1) = {4, 5, 2, 6, 3, 1};<br>
> //+<br>
> Volume(1) = {1};<br>
> //+<br>
> Physical Surface(1) = {6};<br>
> //+<br>
> Physical Surface(2) = {4, 2, 3, 1};<br>
> //+<br>
> Physical Surface(3) = {5};<br>
> //+<br>
> Physical Volume(4) = {1};<br>
> <br>
> Any help is appreciated.<br>
> <br>
> -- <br>
> Anderson Gabriel Santiago<br>
> <br>
> <br>
> ~"If you are depressed,<br>
> you are living in the past.<br>
> If you are anxious,<br>
> you are living in the future.<br>
> If you are at peace,<br>
> you are living in the present."~ - Lao Tzu<br>
</div></div>> ______________________________<wbr>_________________<br>
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<br>
</blockquote></div><br><br clear="all"><br>-- <br><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div><div><div><div>Anderson Gabriel Santiago, Ph.D., E.E.<br>Adjunct Professor, Biomedical Engineering - UFABC<br><a href="mailto:santiago.eletrica@gmail.com" target="_blank">agasantiago.usp@gmail.com</a><br>Cel.: <a href="tel:%2811%29%2099801-0881" value="+5511998010881" target="_blank">+55 11 99801-0881</a><br><br>~"If you are depressed,<br></div> you are living in the past.<br></div> If you are anxious,<br></div> you are living in the future.<br></div> If you are at peace,<br></div> you are living in the present."~ - Lao Tzu</div></div>
</div>