Self Intersecting Surface Mesh

[dgholstein]

I've got a STP file with 2 objects (which the forum doesn't allow me to upload), when I try to open it in Elmer, the program terminates and I get this message:

Code: Select all

WARNING: Intersecting elements 856 and 21
el1 = np = 3 421 423 416
el2 = np = 3 16 20 17
layer1 = 1
layer2 = 1
 WARNING: Intersecting elements 856 and 116
el1 = np = 3 421 423 416
el2 = np = 3 21 20 200
layer1 = 1
layer2 = 1
terminate called after throwing an instance of 'netgen::NgException'
Aborted
danny@turbocow:~/tubes/pseudo_coll> 

BTW: The message from GMSH is:

Code: Select all

Info    : Meshing 3D...
Info    : Meshing volume 1 (Delaunay)
Info    : Meshing volume 2 (Delaunay)
Error   : Self intersecting surface mesh, computing intersections (this could take a while)
Info    : 272 intersecting faces have been saved into 'intersect.pos'
Info    : Done meshing 3D (0.19797 s)
Info    : 473 vertices 1120 elements
Error   : ------------------------------
Error   : Mesh generation error summary
Error   :     0 warnings
Error   :     1 error

Any work arounds? And I get similar behavior on a Windows machine.

[mzenker]

Hi,

this is a known and as yet not completely resolved problem, at least in the open source world: meshing two volumes with a common face. I don't know a simple solution.

You can try one of the following:

* check "cut and merge faces" in gmsh before opening your stp file. Sometimes this feature can heal the duplicated faces.
* do the meshing with Salomé. Here viewtopic.php?f=9&t=1930&p=6049#p6049 (note the corrected wiki link two posts further) and here viewtopic.php?f=9&t=2752&p=9890 are instructions for possible workflows.

HTH,

Matthias