I have some trouble with creating meshes from (complex) step files. When using netgen it works but the model is huge!
So i tries to use gmsh for external mesher. since somehow internal don’t work (probably on my side see https://forum.freecadweb.org/viewtopic.php?f=18&t=28513)
but somehow it fails on rounds and is unable to make volume meshes. see added files.
please can anybody explain how to resolve this?
test_mesh_errors_1.inp.txt (50.2 KB)
test_mesh_errors_1.stp (91.5 KB)
Hi Jee-Bee,
seems that gmsh dont like fillets. I always get a mesh distortion warning, even when
using gmsh directly. Without the little roundings the FEM-run works, see file with cleared mesh.
Are the roundings essential for your Simulation?
gmsh_part.FCStd (57 KB)
Thanks for you’re answer… Even if i don’t like the answer, since i have tons of radii in the real model 
At least to me it looks like gmsh breaks most on small radii… i try to figure out…
for small fillets it needs small elements. Netgen is able to adapt element size to this only in the region of the fillet. Gmsh does this rather poor in standard prefs. Thus one needs to use very smal elements in the whole modell. Would be cool if we could figure out how to get meshes with gmsh like Netgen for modells with small fillets.
Is it known on what gmsh based his element size?
With Gmsh it’s a little bit more expensive.
First you need to edit “shape2mesh.geo” and add the red parameter
// min, max Characteristic Length
Mesh.CharacteristicLengthMax = 3.0;
Mesh.CharacteristicLengthMin = 0.0;
Mesh.CharacteristicLengthFromCurvature = 1;// optimize the mesh
Second you need to isolate the long edge of the fillets, if they share a single face
And result looks like:
Please note, there is no divider line on slot’s faces and therefore mesh won’t grow
tested with Gmsh_4.0.1:
shape2mesh.geo.zip (966 Bytes)
test-mesh.FCStd (173 KB)
crap But that means it is almost impossible to do for complex shapes…
I check what you did… at least it looks more promising as what i do now…
Edit: i’m thinking for what i need it works probably on some extrudes… but not on a moulded parts i have to deal with…