When meshing solids imported from STEP created in FreeCAD, the “Quad-dominated” option does not work for me. This is independent of the PrePoMax version. Does anyone have an idea what affects the use of a cuboid mesh?
Quad-dominated works for surface meshes only - it tries to replace triangular elements with quadrilateral ones. If you want a hexahedral 3D mesh for a solid, you should use one of the Gmsh algorithms: Summary of Gmsh hex meshing rules
for solid part is hex-dominant, but i did not know the reason to not work inside PrePoMax.
some discussion related,
I managed to fix PrePoMax meshing.
None of the tetra meshing options in PrePoMax wanted to work.
In the “C:\PrePoMax v2.2.10 dev\Temp” directory there were error files in which I found text pointing to GMSH.
I downloaded and ran the latest version of GMSH. The program hung on the model. That was the problem.
I searched the disk to find old files left by the GMSH program.
In the “C:\Users.…\AppData\Roaming” directory I found 3 old files:
- gmshrc,
- gmsh-options,
- untitled.geo,
which contained the settings and paths to what I did a few years ago.
The problem is fixed. Meshing is much better and faster.
Thank you for trying to help.
(Machine translation)
gmsh-options:
// Gmsh Option File
//
// This file contains configuration options (preferences) that
// are loaded each time Gmsh is launched. You can create this
// file by hand, or let Gmsh generate it for you (with
// ‘File->Save Default Options’). This file can also be
// automatically saved every time you quit Gmsh if the option
// ‘General.SaveOptions’ is set.
//
General.Axes = 3;
General.BoundingBoxSize = 2.82842712474619;
General.DoubleBuffer = 0;
General.DrawBoundingBoxes = 1;
General.GraphicsFontSize = 16;
Geometry.OCCFixDegenerated = 1;
Geometry.OCCFixSmallEdges = 1;
Geometry.OCCFixSmallFaces = 1;
Geometry.Surfaces = 1;
Geometry.Volumes = 1;
Mesh.ElementOrder = 2;
Mesh.HighOrderOptimize = 2;
Mesh.MeshSizeMax = 1;
Mesh.MeshSizeFromCurvature = 1;
Mesh.MinQuality = 1e+200;
Mesh.OptimizeNetgen = 1;
Mesh.RecombinationAlgorithm = 2;
Mesh.SaveGroupsOfNodes = 1;
Mesh.Smoothing = 100;
Mesh.SurfaceEdges = 0;
Mesh.VolumeFaces = 1;
i checked again in menus to generate hex-dominant mesh, it seems some option is missing in Mesh.Recombine3DAll to be activated (yes/1) instead of default (no/0). Another meshing algorithm setting also in 2D R-Tree options.
result without recombine 3D in latest Gmsh (v4.13.1)
result without recombine 3D in PrePoMax almost identical in pattern and division,
You are right. This option could be added, since the resulting meshes look nice.
That is a nice find. We have already discovered that some settings in these files overwrite the PrePoMax settings, which should not happen.
Problem solved, topic to close. I hope I could help others 
