[cgma-dev] Seg fault when loading OCC geometry with associations

[Jed Brown]

On Sat 2009-03-28 15:02, Tim Tautges wrote:
>
>
> Jed Brown wrote:
>> My brick generator creates some boundary conditions using the Cubit
>> conventions, and creates a geometric model using CGM (built with OCC)
>> via iGeom_createBrick.  If I associate the boundary sets with the brick
>> (wrong, but bear with me) using iRel (geometry first, I get seg-faults
>> if I try mesh first) and save the mesh (in .h5m) and geometry (to a
>> .brep, with TYPE=OCC) then I can load them with another program.  When I
>> try to get the geometric entity related to a boundary set, I get a point
>> instead of the volume that I should get.
>>
>
> Hmm.  Right now, Lasso (my iRel implementation) matches mesh to geometry  
> by matching mesh set global id (GLOBAL_ID tag) and geometric dimension  
> (GEOM_DIMENSION tag) to geom entity global id and type/dimension.  Do  
> the tags on the mesh sets and geom entities match like that?

Since I'm creating the geometry and mesh at the same time, and setting
relations using Lasso, shouldn't this be taken care of?  Both the mesh
and geometry files have tags ASSOCIATION0, but neither GLOBAL_ID or
GEOM_DIMENSION have been applied to my boundary sets.  I'm not sure how
to read the .brep output but there is no mention of GLOBAL_ID or
GEOM_DIMENSION.

Looking at brick_curvy.cub, there is no ASSOCIATION0 tag, but the
boundary sets are tagged with GEOM_DIMENSION=2 and GLOBAL_ID.  The
geometry is in ACIS so I can't load the geometry or view what tags are
present (I don't know how to read a .cub except what MOAB gets from it).
BTW, thanks to whoever made iGeom_load fail for incompatible geometry
engines instead of silently succeeding without loading any geometry.  If
I need to set up these tags manually, do I just make

  MeshSet:GLOBAL_ID      = GeomEnt:GLOBAL_ID
  MeshSet:GEOM_DIMENSION = GeomEnt:GEOM_DIMENSION

(which of course implies that GLOBAL_ID cannot be sequential on both the
mesh and the geometry) or am I misunderstanding you?

> I know that's pretty specific, eventually we may have something more  
> general, but not soon.

I just want to be able to create mesh and geometry, set relationships
using iRel, save the result, and recover the relations.  I don't imagine
the current solution should have trouble with this.


As a separate issue, is there a quick way to get a mesh of a geometric
entity for visualization (can be low quality, ideally triangular strips
for surfaces)?  I assume not yet, but it if we could then it's not a lot
of work to get it into VisIt next to the mesh.


Jed
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