Hi,
Recently, I’ve been working on simple FEM simulations - small elements and simple force cases. Yesterday I tried to create a mesh for a part - screenshots of the part below - but I haven’t got mesh, no matter what type of mesh settings I tried.
Is there any possibility that geometry of the part is too complicated?
Is there any mesh setup that would give me possibility to run FEA/FEM simulation?
Can you share the file ?
It’s always recommended to simplify the model for FEA as much as possible: https://wiki.freecad.org/FEM_Geometry_Preparation_and_Meshing#Geometry_simplification
Sorry, but as a new user I can’t upload attachments other than screenshots…
Anyway, there’s a link to that file:
Can you export STEP from your CAD software ? It’s definitely better to use this format instead of STL for PrePoMax.
Unfortunately, I can’t export that part as a STEP file. Other option is OBJ…
Then let’s stick to STL since OBJ is also a surface mesh format and not supported in PrePoMax.
There are some flaws in this geometry, making it problematic to mesh. You can locate them with the Geometry → Analyze tool:
Okey, so this tool shows where might be problems with creating proper mesh, right?
In my CAD software I can set better export quality, if this could help
Yes, it shows small edges and faces that make meshing difficult or failing. If there are also errors in the geometry, PrePoMax will show a warning sign next to its name.
Try without those fillets:
Okey, I did a quick redesign and now I’ve got this output from Geometry > Analysis tool.
Now, it should be possible to create a mesh?
Is there some kind of min/max values that defines possibility to create a mesh? Do you have some advice for future for me?
Give it a try (you can share the new file too). If it still doesn’t work, you may have to defeature it further (e.g. remove other fillets). PrePoMax also has a defeaturing tool, but it needs STEP geometry.
No, it depends on a case. Some meshers will handle even broken geometries (the ones used in PrePoMax are not so robust, though), but you should always look for geometrical issues and small edges/faces that make meshing difficult (because meshers try to place nodes on all the edges).
Apart from using STEP files (whenever possible) and defeaturing (removing all small and redundant features), as well as correcting flaws such as tiny edges/faces, you can try with just the Meshing Parameters (Netgen) or add Tetrahedral Gmsh. Netgen usually works better, though. Play with the different settings, start from a coarser first-order mesh and then refine (also locally) as needed.
Okey, so here’s the redesigned part:
Also, tried creating basic mesh and it works properly. I used that parameters:
Also, is there any tutorial about mesh settings, local refining, etc.?
Recently I’ve tried Tetrahedral Gmsh but always ended up with “Triangle not found for curvature …” and error “No elements in volume 1”. Do you have any suggestions for that problem?
Yes, now it’s much better and it works even with the default settings. You can then reduce the max element size and/or use local refinement to improve the quality of the mesh.
Mostly about hex meshing (not applicable here), but the FreeCAD wiki page also includes many general tips including mesh convergence studies: https://wiki.freecad.org/FEM_Geometry_Preparation_and_Meshing#Mesh_convergence_studies
FreeCAD uses the same meshers (Netgen and Gmsh), so most tips from there are also applicable in PrePoMax.
As I’ve mentioned, Tetrahedral Gmsh is less robust than the default Netgen, but can generate more regular meshes. So it’s better to use it for clean and relatively simple geometries.
Okey, thanks for your answers, I’ll keep them in mind
For now, I don’t have any questions, so thank you very much for your commitment. I’ll definietly try other settings and try to make better designs. Anyway, you helped me a lot 
Sure, hit me up anytime also via pm if you want to talk in Polish 
You should cut the element into primitives that can be extruded. In extrude, you can set the pyramids to connect into cubes. You can then connect the elements using Tie.
Further simplifying this model could allow (at least partial) hex meshing if not the fact that it can’t be exported to STEP. Perhaps it would be easier to just recreate this part in FreeCAD from which you can export it to STEP and partition as desired (I wonder what forms of partitioning are available in the software you are currently using).
Which software are you using for CAD design?
I’m pretty sure it’s free DesignSpark Mechanical. It indeed doesn’t support STEP format.
As a FEAnalyst guessed, it’s DesignSpark Mechanical. It supports its own format and also STL and OBJ formats
