[cgma-dev] question about iges format (to Jane)

[Jane Hu]

Hi, Iulian,

Opencascade internally assumes that OCC models are measured in millimeters,
so if the model is given in unit M (meter), it'll be changed to 1000times
larger and uses MM(millimeter) in OCC. I am now checking on the code, and
see if we can do something on it.

Jane

On Wed, Jan 18, 2012 at 9:14 AM, Iulian Grindeanu <iulian at mcs.anl.gov>wrote:

> Hi Jane,
> Dan Le found this problem with respect to igs reader:
> Please see the attached files.
> testgeom.cc is a version of CGM/itaps/testgeom.cc file, which also prints
> the coordinates of all the vertices from the model.
> iges format is supported by OCC and Acis/cubit engines.
> Still, the coordinates of the vertices are 1000 larger when occ is used.
> So if you run this test
> testgeom cduct.igs
> in Cubit based cgm or
> testgeom_occ cduct.igs
> in OCC based cgm,
> you get different results (1000 times bigger in occ case). It seems that
> in cubit case, we do a conversion to sat format, first.
>
> ITAPS GEOMETRY INTERFACE TEST PROGRAM:
>
>    gLoad: Reading STEP/IGES file
> '/home/iulian/tmp/test_lorenzo/cduct.igs'...
> Model conversion succeeded: /tmp/CBT.Hoo5yc.sat
> Read 6 ACIS Entities from the input file
>
>
> Constructed 6 Volumes: 1 to 6
> Model contents:
> vertices: 24
> edges: 24
> faces: 6
> regions: 6
> vertex index 0 : 0 0 0
> vertex index 1 : 0 1 0
> vertex index 2 : 10.5 15 0
> vertex index 3 : 11.5 15 0
> ...
>
>  testgeom_occ cduct.igs
> Geometry engine set to: OpenCascade 6.3
>
>
> ITAPS GEOMETRY INTERFACE TEST PROGRAM:
>
>    gLoad: Total number of loaded entities : 78.
>
> Constructed 6 Volumes: 1 to 6
> Model contents:
> vertices: 24
> edges: 24
> faces: 6
> regions: 6
> vertex index 0 : 0 0 0
> vertex index 1 : 0 1000 0
> vertex index 2 : 10500 15000 0
> vertex index 3 : 11500 15000 0
> ...
>
>
>
> Can you please tell me what we should do to get similar results  ?
>
> Thanks,
> Iulian
>
>
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