ill shaped tetrahedra
Hi, I am trying to mesh a geometry containing a big cylindrical container, enclosing 3 other volumes, one of which is a hole (no mesh inside) and two are inclusions (a very small sphere and another cylinder). I use BooleanDifference{ Volume{5}; Delete; }{ Volume{3,4}; Delete; } to remove the mesh in the first entity (please refer to the attached geo file, line 31). Then used BooleanFragments { Volume{5}; Delete; }{ Volume{6,7}; Delete; } to create the 2 inclusions (line 41). I managed to generate mesh but there is a warning of ill shaped tets and it seems I have not been able to efficiently control the mesh size: there are not enough nodes along y-axis, yet a lot of unnecessary nodes along x- and z-axes. I have 3 questions: 1) When I generate mesh it seems the mesh is highly anisotropic, with very long tetrahedra along y-axis. How can I have more control over the dimensions of the tetrahedra in the y-direction and make the elements well-shaped and more isotropic? 2) Since the dimensions of the spherical and the cylindrical inclusions are much smaller than the cylindrical container, how can I adjust the mesh size accordingly. It seems that the cylindrical inclusion has again very long tetrahedra along y-axis. I created a cylindrical field (line 45) to refine the mesh inside the cylindrical inclusion but again the elements are anisotropic. I need much more nodes along y-axis and much less along x and z. 3) My mesh look really messy. I tried to create more structured mesh by creating a disk and then extruding it along y, using layers. But when I generate mesh and use BooleanDifference to create the hole, I still see that the volume that is supposed to be hole, is meshed. How can I use extrude with layers in this case? Please find attached, my geo file. I would very much appreciate your help.afm.geo