[Gmsh] importing/merging geometries

[Mikhail Artemiev]

I had not only this problem when I exported geometry from Salome in step 
file and tried to open it in Gmsh.
For example, if I defined an ellipsoid (see script below) and then opened it 
in Gmsh (or FreeCAD) I got nothing.

import geompy
Sphere = geompy.MakeSphere(-100, -100, -100, 100)
Scale = geompy.MakeScaleAlongAxes(Sphere, None, 1, 3.5, 0.5)
geompy.Export(Scale, "D:/scale.step", "STEP")

I asked about this strange behavior in Salome forum.
One said me:

Indeed, it is a bug (or a limitation, I don't know) ... We will analyze 
that.
For the moment, you should export as brep (this one works and should be 
readable by FreeCAD ans Gmsh)
geompy.Export(Scale, "D:/scale.brep", "BREP")

I exported single sphere, ellipsoid, sphere intersecting cube, in brep 
format - all works fine.
Hope this helps.

But I worry about the difference between step and brep formats for building 
meshes in Gmsh.
Do these formats have the same information about geometry? Or one of these 
is better than other?
Can anybody tell me?

Mikhail Artemiev

----- Original Message ----- 
From: "Bart Vandewoestyne" <Bart.Vandewoestyne at telenet.be>
To: "Mikhail Artemiev" <artemiev.mikhail at ngs.ru>
Sent: Tuesday, May 10, 2011 4:31 PM
Subject: Re: importing/merging geometries


> On Tue, May 10, 2011 at 11:45:24AM +0700, Mikhail Artemiev wrote:
>> Hi, Bart!
>>
>> On 23 March 2011 you wrote:
>>
>> ----------
>>
>> Thanks for pointing me to Salome.  I've played a bit around with
>> it and created a simple 3D geometry consisting of the union of a
>> cube and a sphere:
>>
>>  http://www.kuleuven-kortrijk.be/~bartv/cube_and_sphere.hdf
>>
>> I exported this to a STEP file:
>>
>>  http://www.kuleuven-kortrijk.be/~bartv/cube_and_sphere.step
>>
>> but when I try to open this STEP file in gmsh with
>>
>>  $ gmsh cube_and_sphere.step
>>
>> i get errors:
>>
>>  Error   : Something wrong in edge loop
>>  Warning : OCC STL triangulation failed
>>
>> ------------
>>
>> I encountered with the same problem using FreeCAD and Salome.
>> Did you solve this problem?
>
> Nope.  Haven't received a solution and haven't looked at it
> anymore...  it's not so urgent for me.  If you have solutions,
> please share!
>
> Regards,
> Bart
>
> -- 
> "Share what you know.  Learn what you don't."