<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div class="">Hi -</div><div class=""><br class=""></div><div class="">I run into the issue that the following commands:</div><div class=""><br class=""></div><blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;" class=""><div class=""><div class="">SetFactory("OpenCASCADE");</div></div><div class=""><div class="">Cylinder(1) = {-1, -0, 0, 2, 0, 0, 4, 2*Pi};</div></div><div class=""><div class="">Cylinder(2) = {-1.1, -0, 0, 2.2, 0, 0, 0.5, 2*Pi};</div></div><div class=""><div class="">BooleanDifference{Volume{1}; Delete; }{Volume{2};Delete;}</div></div><div class=""><div class="">Physical Surface(1000) = {4};</div></div></blockquote><div class=""><br class=""></div><div class="">followed by 3D meshing and write to a .msh file, do not result in a mesh file that contain the 3D results. The message console indicates that 204 nodes and 1029 are generated, they are nicely shown in the GUI, yet the saved output file has only 17 nodes and 26 triangular elements. This result is the same for different .msh file output formats, so that does not appear to be the issue. However, when I leave out the "Physical Surface(1000) = {4};”, the mesh file does contain the complete results. </div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">Info : Gmsh version : 4.0.1</div><div class="">Info : Build OS : MacOSX</div><div class="">Info : Build options : 64Bit Ann Bamg Bfgs Blas(Custom) Blossom Cgns DIntegration Dlopen Fltk Gmm Hxt Jpeg(Fltk) Kbipack Lapack(Custom) MathEx Med Mesh Metis Mmg3d Mpeg NativeFileChooser Netgen ONELAB ONELABMetamodel OpenCASCADE OpenGL OptHom PETSc Parser Plugins Png(Fltk) Post SLEPc Solver TetGen/BR Voro++ Zlib</div><div class="">Info : Build date : 20180907</div><div class="">Info : Build host : <a href="http://gmsh.info" class="">gmsh.info</a></div><div class="">Info : Packager : geuzaine</div><div class="">Info : Executable : /Applications/Gmsh.app/Contents/MacOS/gmsh</div><div class="">Info : Launch date : Mon Sep 24 09:35:54 2018</div><div class="">Info : Command line : /Applications/Gmsh.app/Contents/MacOS/gmsh</div><div class=""><br class=""></div></body></html>