diff --git a/doc/FAQ b/doc/FAQ index 38601870cc6a09038c25089cf8e38d844b51f803..e9095e3f2a5852f5986f6b07204f9f908a9680e2 100644 --- a/doc/FAQ +++ b/doc/FAQ @@ -1,4 +1,4 @@ -$Id: FAQ,v 1.57 2005-03-24 18:59:18 geuzaine Exp $ +$Id: FAQ,v 1.58 2005-03-24 20:35:44 geuzaine Exp $ This is the Gmsh FAQ @@ -17,7 +17,7 @@ capabilities. * 1.2 What are the terms and conditions of use? Gmsh is distributed under the terms of the GNU General Public -License. See the file doc/LICENSE for more information, or go to the +License. See the file 'doc/LICENSE' for more information, or go to the GNU foundation's web site at http://www.gnu.org. * 1.3 What does 'Gmsh' mean? @@ -29,10 +29,10 @@ Nothing ;-) * 1.4 Where can I find more information? -<http://www.geuz.org/gmsh/> is the primary location to obtain +http://www.geuz.org/gmsh/ is the primary location to obtain information about Gmsh. You will for example find a complete reference manual as well as a searchable archive of the Gmsh mailing list -(<gmsh@geuz.org>) on this webpage. +(gmsh@geuz.org) on this webpage. ******************************************************************** @@ -49,7 +49,7 @@ system, provided that you have access to a recent C and C++ compiler. You should have the OpenGL libraries installed on your system, and in the path of the library loader. A free replacement for OpenGL can be -found at <http://www.mesa3d.org>. +found at http://www.mesa3d.org. * 2.3 What do I need to compile Gmsh from the sources? @@ -62,24 +62,21 @@ the libpng and zlib libraries if you want to save png images. Under Windows, you will need the Cygwin tools and compilers (freely available from http://www.cygwin.com), as well as "cygwin-enabled" -version of FLTK (i.e., you have to configure FLTK with "./configure ---enable-cygwin"). +version of FLTK (i.e., you have to configure FLTK with './configure +--enable-cygwin'). * 2.4 How to I compile Gmsh? -Just type - -./configure; make; make install - -If you change some configuration options (type ./configure --help to -get the list of all available choices), don't forget to do 'make -clean' before rebuilding Gmsh. +Just type './configure; make; make install'. If you change some +configuration options (type './configure --help' to get the list of +all available choices), don't forget to do 'make clean' before +rebuilding Gmsh. ******************************************************************** Section 3: General problems -* 3.1 Gmsh [from a binary distribution] complains about missing +* 3.1 Gmsh (from a binary distribution) complains about missing libraries. Try 'ldd gmsh' (or 'otool -L gmsh' on Mac OS X) to check if all the @@ -95,18 +92,25 @@ Disable opaque move in your window manager. * 3.3 The graphics display very slowly. Are you are executing Gmsh from a remote host (via the network) -without GLX? You should turn double buffering off (with the -nodb +without GLX? You should turn double buffering off (with the '-nodb' command line option). -* 3.4 Why is there an ugly "ghost" triangulation in the vector -PostScript/PDF files generated by Gmsh? +* 3.4 There is an ugly "ghost triangulation" in the vector +PostScript/PDF files generated by Gmsh! + +No, there isn't. This "ghost triangulation" is due to the fact that +most PostScript previewers nowadays antialias the graphic primitives +when they display the page on screen. (For example, in gv, you can +disable antialising with the 'State->Antialias' menu.) You should not +see this ghost triangulation in the printed output (on paper). + +* 3.5 How can I save GIF, JPEG, ..., images? + +Just choose the appropriate format in 'File->Save As'. + +* 3.6 How can I save MPEG, AVI, ..., animations? -Actually, there isn't. This "ghost triangulation" is due to the fact -that most PostScript previewers nowadays antialias the graphic -primitives when they display the page on screen. (For example, in gv, -you can disable antialising with the 'State->Antialias' menu.) You -should not see this ghost triangulation in the printed output (on -paper). +See question 7.9. ******************************************************************** @@ -140,9 +144,9 @@ Section 5: Mesh module * 5.1 What should I do when the 2D unstructured algorithm fails? Try one of the other 2D algorithms, e.g.: -- on the command line: gmsh -algo tri -- in the interface: Tools->Options->Mesh->2D->Isotropic algorithm (Triangle) -- in input files: Mesh.Algorithm = 3 +- on the command line: 'gmsh -algo tri' +- in the interface: 'Tools->Options->Mesh->2D->Isotropic algorithm (Triangle)' +- in input files: 'Mesh.Algorithm = 3' The old 2D algorithm may disappear once all its features are integrated in the new ones, so please don't send bug reports on the old algorithm anymore. @@ -180,7 +184,7 @@ very big meshes, see the answer to the previous question... * 5.6 The quality of the elements generated by the 3D algorithm is very bad. -Upgrade to Gmsh >= 1.54 and use "Optimize quality". If badly shaped +Upgrade to Gmsh >= 1.54 and use 'Optimize quality'. If badly shaped elements still exist due to the surface recovery step, you can try to use Netgen instead of the default algorithm for the 3D mesh. Note that all surface meshes have to be oriented with exterior normals in this @@ -196,10 +200,10 @@ hexahedra instead of tetrahedra. This is fixed in Gmsh >= 1.54. However, when region numbers are explicitly assigned to mesh entities in the extrude commands (which -partially destroys the geometry/mesh relationship), the Visibility -tool will only work as expected when displaying Elementary +partially destroys the geometry/mesh relationship), the 'Visibility' +tool will only work as expected when displaying elementary entities. In this particular case, the only solution to visualize -extruded Physical entities is to save the mesh, and to read it again. +extruded physical entities is to save the mesh, and to read it again. * 5.9 Does Gmsh support curved elements? @@ -213,7 +217,7 @@ option panel. From the command line, you can also use '-order 2'. build a 3D mesh? Yes, either in the form of a STL triangulation, or by using the -"Discrete Surface" commands. Note that Gmsh cannot currently modify +'Discrete Surface' commands. Note that Gmsh cannot currently modify the surface mesh you provide in this way, so the surface mesh has to be conform (without gaps, hanging nodes, etc.) and must contain surface elements having the (final) desired sizes. @@ -228,8 +232,8 @@ of elements, and it is up to the solver to interpret these tags as boundary conditions, materials, etc. Associating tags with elements in Gmsh is done by defining Physical entities (Physical Points, Physical Lines, Physical Surfaces and Physical Volumes): see the reference -manual as well as the tutorials (in particular tutorial/t1.geo) for a -detailed description and some examples. +manual as well as the tutorials (in particular 'tutorial/t1.geo') for +a detailed description and some examples. ******************************************************************** @@ -249,14 +253,14 @@ calls inside your program. You will of course also need to define your solver commands in an option file, but this time you should set the ClientServer variable to 1 (e.g. Solver.ClientServer = 1). C, C++, Perl and Python solver examples are available in the source -distribution in the utils/solvers directory. +distribution in the 'utils/solvers' directory. * 6.2 On Windows, Gmsh does not seem to find the solver executable. What's wrong? The solver executable (for example, 'getdp.exe') has to be in your path. If not, simply go to the solver options (for example, -Solver->GetDP->Options->Executable) to specify its location. +'Solver->GetDP->Options->Executable') to specify its location. On recent versions of Microsoft Windows (XP SP2), it seems that you need to execute the solver (e.g. launch 'getdp.exe') at least once @@ -276,10 +280,10 @@ Section 7: Post-processing module Use 'View->Plugins->Cut Plane'. -* 7.2 Can I save isosurfaces to a files? +* 7.2 Can I save an isosurface to a file? -Yes: first run the CutMap plugin to extract the isosurface, then use -'View->Save As' to save the new view. +Yes: first run 'View->Plugins->Cut Map' to extract the isosurface, +then use 'View->Save As' to save the new view. * 7.3 Can Gmsh generate isovolumes? @@ -323,9 +327,9 @@ point to the second view. (You might want to make the second view invisible, too. If you want to amplify or decrease the amount of deformation, just modify the 'Displacement factor' option.) -Another solution is to use the "general transformation expressions" -(in View->Options->Offset) on the field you want to display, with the -displacement map selected as the transformation data source. +Another solution is to use the 'General transformation expressions' +(in 'View->Options->Offset') on the field you want to display, with +the displacement map selected as the transformation data source. And yet another solution is to use the DiplacementRaise plugin. @@ -343,8 +347,8 @@ Yes, using the CutMap plugin. * 7.9 Is there a way to save animations? -Yes. For example, have a look at tutorial/t8.geo or -demos/anim.script. +Yes, using scripts. Have a look at 'tutorial/t8.geo' or +'demos/anim.script' for an example. * 7.10 Is there a way to visualize only certain components of vector/tensor fields?