<html><head><meta http-equiv="Content-Type" content="text/html; charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Dear Maikol,<div class=""><br class=""></div><div class="">GATE use the surface described by the mesh file to create a solid. Like you saw with your example it produce a volume with the material you specified.</div><div class="">The GATE class that read the .stl mesh file and creates a solid uses the Geant4 class G4TessellatedSolid. </div><div class=""><br class=""></div><div class="">In the GATE documentation:</div><div class=""><a href="http://wiki.opengatecollaboration.org/index.php/Users_Guide:Defining_a_geometry#How_to_build_a_.22tessellated.22_volume" class="">http://wiki.opengatecollaboration.org/index.php/Users_Guide:Defining_a_geometry#How_to_build_a_.22tessellated.22_volume</a></div><div class=""><br class=""></div><div class="">In the Geant4 documentation:</div><div class=""><a href="https://geant4.web.cern.ch/geant4/UserDocumentation/UsersGuides/ForApplicationDeveloper/html/Detector/Geometry/geomSolids.html#tessellated-solids" class="">https://geant4.web.cern.ch/geant4/UserDocumentation/UsersGuides/ForApplicationDeveloper/html/Detector/Geometry/geomSolids.html#tessellated-solids</a></div><div class=""><br class=""></div><div class="">Hope this helps,</div><div class="">  Maxime Chauvin</div><div class=""><br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On 9 Feb 2018, at 10:59, maik sal <<a href="mailto:mmsalas@gmail.com" class="">mmsalas@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">

<span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline" class="">Dear Gate-Users</span>

<br class=""><div class="gmail_extra"><br class=""></div><div class="gmail_extra">Someone knows how GATE interprets the Mesh structures, mainly Mesh structures are a shell, I mean it only represents the surface and inside are empty. Only Volumetric Mesh (3D Mesh) are full inside, then I am not sure if Gate interprets the mesh surface as a boundary and everything inside in an specific material or I have to use Volumetric Mesh (3D Mesh).</div><div class="gmail_extra"><br class=""></div><div class="gmail_extra"><b class="">Wikipedia definition: 

<span style="color:rgb(34,34,34);font-family:sans-serif;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial" class="">Volumetric meshes</span><span style="color:rgb(34,34,34);font-family:sans-serif;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline" class=""><span class=""> </span>are a polygonal representation of the interior volume of an object. Unlike<span class=""> </span></span><a href="https://en.wikipedia.org/wiki/Polygon_mesh" title="Polygon mesh" style="text-decoration:none;color:rgb(11,0,128);background:none rgb(255,255,255);font-family:sans-serif;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px" class="">polygon meshes</a><span style="color:rgb(34,34,34);font-family:sans-serif;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline" class="">, which represent only the surface as polygons, volumetric meshes also discretize the interior structure of the object</span></b>

</div><div class="gmail_extra"><br class=""></div><div class="gmail_extra">In some test that I made to mask a source, it looks like GATE interprets the volume inside of the surface as a volume with the specific material that I specified, but if someone knows this with more detail I appreciate your help.</div><div class="gmail_extra"><br class=""></div><div class="gmail_extra">Best regards</div><div class="gmail_extra"><br class=""></div><div class="gmail_extra">Maikol</div></div>
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