Hi Dr. Geuzaine, Thanks for your response. I see the problem here now. It doesn't work after meshing, although the geometry seems to load to the GUI. Unfortunately, I need to split a surface into two surfaces, and it seems there's no way to do that to the STEP file using what's available under the OpenCASCADE kernel right now. I was hoping to be able to convert the STEP to gmsh-style geometry, then delete a surface (and its dependent volumes) and replace it with a new, split one. I'll just have to change the CAD then re-export, I suppose.
Thanks again! On Wed, Apr 3, 2019 at 3:11 PM Christophe Geuzaine <[email protected]> wrote: > > > > On 3 Apr 2019, at 18:23, Gavin Ridley <[email protected]> > wrote: > > > > Hi, > > > > I would just like to note something to the developers regarding a > perhaps unnecessary skipping of surfaces in the code. > > > > I recently have had to convert a STEP file with fairly complicated > geometry to a GEO. > > Don't do that. By design, Gmsh never translates from one CAD format to > another. The "unrolled GEO" feature is there for unrolling complex GEO > scripts. It can indeed export a limited subset of geometrical entities > created by other CAD kernels, but it's there only for debugging. > > If you want to modify a STEP model, set > > SetFactory("OpenCASCADE"); > > at the beginning of your script. Since we import STEP models with > OpenCASCADE, this will allow you to modify the file directly with > OpenCASCADE. See > https://gitlab.onelab.info/gmsh/gmsh/blob/master/demos/boolean/import.geo > for an example. > > Christophe > > > > > > This is done so that I can split one of the surfaces in the STEP file to > set different BCs on different parts of the surface. At the moment, it > appears that gmsh will skip several surfaces in the conversion from STEP to > geo_unrolled unnecessarily: surfaces were left out from the gmsh file. A > warning message comes with this. > > > > It seems, however, that the skipped surfaces work fine if you just go > back in and add surfaces manually. Gmsh now reads the geo file correctly. > > > > So, why are these surfaces being skipped? Is there some ambiguity about > their interpretation from STEP? It would be nice to not have to manually go > in and add the surfaces. > > > > -- > > Thanks, > > Gavin Ridley > > _______________________________________________ > > gmsh mailing list > > [email protected] > > http://onelab.info/mailman/listinfo/gmsh > > — > Prof. Christophe Geuzaine > University of Liege, Electrical Engineering and Computer Science > http://www.montefiore.ulg.ac.be/~geuzaine > > > > -- Thanks, Gavin Ridley
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