CFD Online Discussion Forums

CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)
-   OpenFOAM Meshing & Mesh Conversion (https://www.cfd-online.com/Forums/openfoam-meshing/)
-   -   [CAD formats] Tool for Surface Preparation for SnappyHexMesh (https://www.cfd-online.com/Forums/openfoam-meshing/61516-tool-surface-preparation-snappyhexmesh.html)

bastil July 27, 2008 15:35

Tool for Surface Preparation for SnappyHexMesh
 
Hi group,

after I tested SnappyHexMEsh I think it is a great tool. What I am still seeking for is a tool to do some preparations on surface (convert iges-geometry to mesh, split surface into parts, name parts, save as stl...)
I am considering tools like blender or gmsh for that. What do others use for this? Any recommendations? Thanks.

andersking July 27, 2008 22:51

Hi, Typically I use blende
 
Hi,

Typically I use blender for my geometry creation. Quite good (and fast), once you get used to the interface.

The default stl export from blender is not so great. Especially as binary stl's seem to give one patch per facet in OF-1.5.

I have an ascii stl export script which I will post when its done. Allows ascii export with named objects/surfaces. These names can then be directly used in snappyHexMesh as patches/refinement areas.

Cheers,
Andrew

fra76 July 28, 2008 03:03

As far as I know, binary STL c
 
As far as I know, binary STL cannot contain patch names as strings, that's why you have only one patch. You will have the same behaviour if you load that STL into another program, I guess.

Bye,
Francesco

olesen July 28, 2008 03:18

I haven't actually tried it, b
 
I haven't actually tried it, but can't you use other formats instead of stl? Eg, I find the Wavefront .obj quite nice to work with.

Since the type is 'triSurface', I think it should handle any of the supported input formats: stl, gts, obj, off, tri, ac, nas.

andersking July 28, 2008 06:07

Well, that answers my question
 
Well, that answers my question then ;-).

Anyway I only use stls as that was the best format I could find that was supported by netgen/gmsh and blender. Haven't tried any of the others.

Anyway, I have posted the script in another thread, http://www.cfd-online.com/OpenFOAM_D...5095#POST25114

Cheers,
Andrew

billy July 28, 2008 13:15

I use Rhino which I found is l
 
I use Rhino which I found is low cost compared to other CADs. You can download the evaluation version and test it.

If you want something free, maybe you can try FreeCAD.

bastil July 28, 2008 16:58

I did some tries with gmsh and
 
I did some tries with gmsh and blender now. Using the motorbike from the tutorials both of them obviously only import the first part of the motorbike. How can these multi-part stls be handled?
Thanks.

elvis July 31, 2008 07:07

Hi all, VTK comes with seve
 
Hi all,

VTK comes with several Reader and Writer libraries for
Wavefront .obj vtkOBJReader http://www.vtk.org/doc/nightly/html/...OBJReader.html
STL (ascii/binary) writer vtkSTLWriter

so converting should be easy

elvis

elvis July 31, 2008 12:44

Hi, MeshLab http://meshlab.
 
Hi,

MeshLab http://meshlab.sourceforge.net/ might be a good choice for converting from
# import:PLY, STL, OFF, OBJ, 3DS, COLLADA, PTX
to STL

elvis

billy August 1, 2008 07:05

It depends. If you have an
 
It depends.

If you have an IGES or STEP format to begin with, the only free tool I can think of would be based on OpenCASCADE technology. OpenCASCADE has an MFC example for import (IGES, STEP, BREP) and export (IGES, STEP, BREP, STL).

mediode August 1, 2008 07:47

Hi, maybe ls-prepost may be
 
Hi,

maybe ls-prepost may be of interest for someone. It reads IGS, STP, VDA and couple of others and exports STL (&more) as well (furthermore it can customized).
Dowmload was a bit tricky, check out the googlegroup.

http://www.lstc.com/lspp/

bastil August 3, 2008 18:01

I agree with Billy that having
 
I agree with Billy that having geometry tools are limited (I see OpenCascade-based Salome and gmsh). However, I have suface meshes in stl (like the motorbike tutorial) and want to regroup or modify it.
Problem with the tutorial for gmsh, Blender and Paraview: I can only import one of the groups... So I do not get he complete motorbike.

Regards.

andersking August 3, 2008 21:30

Hi, If you can't find a to
 
Hi,

If you can't find a tool (and you're a sucker for punishment ;-) ), you can always open up the ascii stl and save each

solid <name>
...
endsolid


group as a separate file. I think it should be easy to script this. Alternatively you can use admesh ( http://www.varlog.com/index.html ) to convert an ascii stl to binary - this combines the all the groups into one (unfortunately losing all the group information though - see Francesco's post above).

Cheers
Andrew

eugene August 4, 2008 06:50

surfaceSplitByPatch?
 
surfaceSplitByPatch?

gocarts August 4, 2008 09:53

You might want to take a look
 
You might want to take a look at SymLab with its Exchange add-on that imports/exports IGES, STEP and STL. For full geometry creation and meshing control consider the Professional add-on.

The SymLab framework uses OpenCascade as its geometry engine, VTK for visualization and wxWidgets as its cross-platform GUI.

In the works is an OpenFOAM add-on to seamlessly setup, mesh, run and visualize cases within SymLab.

Full Disclosure: I represent Symscape the developer of SymLab.

billy August 5, 2008 13:27

VariCAD is also a pretty affor
 
VariCAD is also a pretty affordable CAD system for linux:

http://www.varicad.com

I tried ASCON free KOMPAS LT but unfortunately it doesn't have STL export.

http://ascon.net/download.php

billy August 5, 2008 13:53

This might be also interesting
 
This might be also interesting:

http://www.susqu.edu/facstaff/b/brak...r/evolver.html

It seems to be able to read IGES.

roth August 5, 2008 17:16

Another option is to use Googl
 
Another option is to use Google Sketchup (free):
http://sketchup.google.com/

Then export with the su2stl Sketchup add-on (free):
http://www.crai.archi.fr/RubyLibrary...m_fil_page.htm

segersson November 17, 2008 16:49

Hi, I just stumbled on the ne
 
Hi,
I just stumbled on the new CADspan plugin for Sketchup (http://www.cadspan.com/). It seems to be a perfect tool to clean up and export water tight STL-files from Sketchup. They want a small fee for commercial users though.


All times are GMT -4. The time now is 19:37.