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0022805Community[OCCT] OCCT:Data Exchangepublic2011-11-11 13:552012-03-29 17:26
[OCCT] 6.5.2 
[OCCT] 6.5.3[OCCT] 6.5.3 
chl 934 R7
0022805: Bug of STEP read /writer
Post from the Forum - [^]
"After exporting a B-spline surface to STEP and importing it back to OCC, the surface is not displayed correctly in shaded mode (see image in the appendix). Wireframe mode is displayed correctly, also iso-lines can be shown, so the geometry is basically there, but shading fails. As far as I know such problems often point to some geometrical problems.

The problem occurs only after the surface was sewed together with other surfaces to form a solid.
However, according to DRAW's "checkshape" this solid is valid.
Furthermore, the problem does not occur if the surface spans less than 360°.

The problem occurs in OCC 6.5.1 as well as in OCC 6.3.1. Other versions, I dind't test.

With other export formats (BREP, IGES, STL) there is no problem.

I append some brep files:
spiral_original_surface.brep the surface before sewing (no problem)
spiral_solid.brep the sewed solid
spiral_solid_face.brep the surface after sewing
spiral_solid_359_degree the sewed solid spanning only 359 degree (no problem)

Bug is reproduced under OCCT6.5.2 also.
Shape before export in step is valid, but after import becomes invalid.
See below bug reproducer.
> pload ALL
> restore spiral_solid.brep s
> checkshape s
## Ok
> stepwrite 0 s s.stp
> stepread s.stp r *
> checkshape r_1
## On Shape faulty_1 :
## BRepCheck_SelfIntersectingWire
## On Shape faulty_2 :
##Shape faulty_1 on shape faulty_2 :

##Faulty shapes in variables faulty_1 to faulty_2
Modified the process of translating edge loop from STEP file to OCC: if computation of 2D parameter of vertices on edge gives the same result, update range of edge isn't done.
No tags attached.
zip (329,099) 2011-11-11 13:55
? R7 (948) 2012-02-10 10:01
Issue History
2011-11-11 13:55szyNew Issue
2011-11-11 13:55szyAssigned To => gka
2011-11-11 13:55szyFile Added:
2011-12-15 16:17abvAssigned Togka => ama
2011-12-15 16:17abvStatusnew => assigned
2012-02-03 18:55amaNote Added: 0019393
2012-02-03 18:56amaAssigned Toama => gka
2012-02-03 18:56amaStatusassigned => resolved
2012-02-06 12:10gkaAssigned Togka => ama
2012-02-06 12:10gkaStatusresolved => reviewed
2012-02-08 12:40apnTest case number => chl 934 R7
2012-02-10 10:00apnNote Added: 0019499
2012-02-10 10:00apnNote Edited: 0019499bug_revision_view_page.php?bugnote_id=19499#r3424
2012-02-10 10:01apnFile Added: R7
2012-02-10 10:01apnStatusreviewed => tested
2012-02-10 14:27bugmasterNote Added: 0019507
2012-02-10 14:27bugmasterStatustested => verified
2012-02-10 14:27bugmasterResolutionopen => fixed
2012-02-10 18:08amaAdditional Information Updatedbug_revision_view_page.php?rev_id=3435#r3435
2012-02-10 18:10amaAdditional Information Updatedbug_revision_view_page.php?rev_id=3436#r3436
2012-03-29 17:26bugmasterChangeset attached => occt master e65d641a

2012-02-03 18:55   
SVN branch http://svn/svn/occt/branches/OCC22805 [^] (revision 10306) is ready to be reviewed.
2012-02-10 10:00   
Dear BugMaster,
  Workbench KAS:dev:apn-22805-occt was created from SVN branch http://svn/svn/occt/branches/OCC22805 [^]
  (and apn-22805-products from trunk) and compiled on Linux and Windows platforms.
  There are not regressions in apn-22805-products regarding to KAS:dev:products-20120203-opt

Test case for this fix is chl 934 R7. It's OK.
  See results in /QADisk/occttests/results/KAS/dev/ apn-22805-products_08022012/lin
  See reference results in /QADisk/occttests/results/KAS/dev/products-20120203-opt_03022012/lin
  See test cases in /QADisk/occttests/tests/ED

2012-02-10 14:27   
Integrated into trunk of occt repository

Date: 2012-02-10 14:09:30 +0400 (Fri, 10 Feb 2012)
New Revision: 10410