[Gmsh] STEP import // tangent surface selection

[Michael Hiller]

Hello Christophe, did you ever get an answer to following archived email?
 http://onelab.info/pipermail/gmsh/2013/007826.html

  I am not a coding expert but I found following description on the occ-site which seems to be exactly what me and the Matthias were looking for:
 
 https://www.opencascade.com/doc/occt-6.7.0/overview/html/user_guides__step.html#occt_step_7_1_1
 
 It would be great if you could implement color and name STEP import.
 
 There seems to be the possibility for layer import as well which would be a nice extra:
https://www.opencascade.com/doc/occt-6.9.1/refman/html/class_s_t_e_p_c_a_f_control___reader.html#afa81144a8d9116e1ffa0af30a70f928e
 
 Let me know if I can check or provide more information.
 
 Thank you and best regards
 Michael

      From: Michael Hiller <postanmichel at yahoo.com>
 To: "gmsh at geuz.org" <gmsh at geuz.org> 
 Sent: Thursday, August 25, 2016 12:55 PM
 Subject: STEP import // tangent surface selection
   
Dear Gmsh developers, dear users,

first of all I want to thank you for fixing the higher order compound feature – it works like charm now!

I am trying to find a solution how to easily define "Compound Surfaces" now. I have a solid STEP model with almost 1500 surface patches. In the end I want all patches that share a tangent edge to be meshed together as a single compound mesh.

At the moment I have to manually select the patches. It helps to hide by group selection with pressing STRG and drawing a rectangular box in the GUI. But still this is cumbersome for the complete part.

So I was thinking maybe there is something like "Reclassify 2D" for STEP files which I couldn’t find.

Unfortunately I also cannot use some helpful STEP options like exporting feature names or surface colors. With the first option I could do the compound definitions inside CAD. This would generally be a neat feature: you could parametrically define interfaces inside CAD and use them in GMSH for physical entities. I think that the OCC kernel provides option.

Also I don't see an obvious way how to change the surface IDs stored inside the STEP file. This could help by writing a little python script to group surfaces by ordering them inside the step file.

I would be very happy if anyone could provide some further ideas on how to approach this more conveniently.

Thank you and best regards
Michael



   
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