[Gmsh] Duplicate Surfaces Issue from .Step import

[Bill Milewski]

Hi Aaron,

I include the following lines at the beginning of my geo files.    My CAD
is created and exported from Rhino as a STP file, and has units of meters.

Geometry.Tolerance = 0.001;
Geometry.OCCSewFaces = 1;

If the tolerance is set too tight, the CAD kernel in gmsh treats the trim
curves from neighboring surfaces as independent curves.  You may also need
to change the degree of the surfaces in the CAD model so it is consistent
across all of the patches.  I have had good success with bicubic NURBS.
You may also need to ensure that neighboring patches have a similar number
of control points along shared boundaries.

Good luck,

Bill


On Mon, Feb 8, 2016 at 6:30 AM, Aaron Kiefer <AKiefer at accident-research.com>
wrote:

> GMSH Group,
>
>
>
> I’m still working with importing a .step surface file to create a 2D mesh
> for PC-Crash.  The model has been separating when I try to analyze it.
> Inspection of the .geo file indicates redundant points, lines, and faces
> along common surfaces of the model.  For reference, I copied one set of
> offending surfaces, lines, and points from the .geo file and typed them
> below. Is there a way to tell GMSH to remove the duplicate points, lines,
> and surfaces before or during meshing?  From reading the help,  the sew
> faces command sounds like what I need.  I tried opening the .Step file
> using the below ‘sew faces’ box checked before saving as a .geo but that
> didn’t change anything…
>
>
>
> Plane Surface(40) = {131,-133, -128, 132};
>
> Plane Surface(48)  = {161, -162, -163, 159};
>
> Line(161) ={111, 113};
>
> Line(133)={90,92};
>
> Point(90) = {177.8000000000002, 15.87499999999997, 130.5089814427782,
> cl__1};
>
> Point(113) = {177.8000000000004, 15.87499999999994, 130.5089814427785,
> cl__1};
>
>
>
> Thanks in advance for any suggestions,
>
>
>
> *Aaron J. Kiefer MSME, PE*
>
> *Accident Research Specialists, PLLC*
>
> 1631 NW Maynard Road, Suite 101
>
> Cary, NC 27513
>
> *Phone:  (919) 467-8134 <%28919%29%20467-8134>*
>
> *Fax:        (919) 678-1261 <%28919%29%20678-1261>*
>
> *Cell:        (919) 810-8429 <%28919%29%20810-8429>*
>
> *Email:*    akiefer at accident-research.com
>
> *Web:*      www.accident-research.com
>
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