Gmsh Options

disla

I'm trying to figure how do the gmsh options button work.
I have mesh an stp file in gmsh and save the opt file.
I have copy and paste the same opt in Mecway but it do not get the same mesh.
¿Has someone experience this feature?
I was planing to leave the general mesh options feature pasted and control the mesh result through that large variety of parameters available.
Thanks

Victor

It's supposed to work like that. Just be careful of the options that Mecway adds in the top and bottom panels since some might conflict with your own (Mesh.Format). The .opt file sent to Gmsh is the contents of the 3 boxes concatenated together.

I can't seem to get Gmsh to mesh this file at all through Mecway. Is that what's happening for you too and it does work with Gmsh directly?

disla

I'm using gmsh-3.0.6.Maybe that's the reason.
For me meshing on mecway with gmsh works but do not reproduce the same mesh as directly in gmsh.

Victor

If you manually paste the 3 panels' contents together into a .opt file, and run it directly in Gmsh, does that match Mecway? That would show if it's those extra lines doing it.

disla

MECWAY 9 New feature: “Button to import Gmsh commands from a file”.

¿Is it possible to remove any additional lines to the custom settings coming from the default Mecway configuration?
Some of them override custom parameters. I have attached a pdf to explain myself better.
I think it will also avoid malfunctioning in case of future Gmsh updates.

Thanks

Victor

That's a good point. I'm not sure the best way to do this because the UI for Gmsh is already getting a bit complicated, but I'll try to add a checkbox or something to disable them.

I think Mesh.Format = 1; should remain because 1 (msh) is explicitly the format that Mecway imports and I don't know if 10 (automatic) might sometimes or in future cause it to use a different format. Any comments on that?

disla

I agree with you that Mesh.Format = 1 should remain.
As Andrea anticipated Gmsh is preparing a new version (v4) that has been announced as a big improvement.(GMSH Hex generator library will be included)
Hope Mecway can take advantage of this new features.

disla

Seems there is an issue with the scale factor of the mesh generated by GMSH.
I have tested custom commands with v3.0.7 (latest automatic) and it works apart from this.
Mesh.Format = 1; set manually in custom parameters
I suppose it is some kind of units bad import .
Solved with Mesh.ScalingFactor = 1000; set manually in custom parameters

Victor

Thanks for spotting that. I found Gmsh 3.0.6 (latest stable) works OK but 3.0.7 (latest automatic) has this scaling problem, so for now I'll assume it's a bug in the non-stable Gmsh.

Mecway assumes the output from Gmsh is in mm because that's how it used to be. It looks like they've changed it to meters which is going to break everything for everyone - hence why it seems more like a bug.

disla

1-Generate the mesh with custom parameters, gmsh or netgen.
2-Mesh tools/ Automesh 3D.
3-Generate the mesh with custom parameters, gmsh or netgen again.

Two meshes are overlaped. The one coming from automesh is not reset.

Victor

That behavior is intentional. The mesh made from a STEP/IGES file is linked to that file so it gets replaced when you remesh it. But any other mesh, such as made with the Mesh tools menu isn't linked to anything and doesn't get updated. It's a bit of a grey area how much you can modify a linked mesh while keeping it linked, but usually you wouldn't modify it at all.

Automesh 3D is meant for things like STL files, orphaned meshes, or to fill the interior of a hollow shape. That's usually a separate workflow from importing a STEP/IGES file.