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|ID||Project||Category||View Status||Date Submitted||Last Update|
|0029060||Open CASCADE||[OCCT] OCCT:Modeling Algorithms||public||2017-08-28 10:14||2017-09-15 12:15|
|Product Version||[OCCT] 7.2.0|
|Target Version||[OCCT] 7.4.0*||Fixed in Version|
|Summary||0029060: BRepOffset_MakeOffset produces invalid shape in test bugs modalg_7 bug28131|
|Description||Standard offset algorithm BRepOffset_MakeOffset produces invalid shape in test bugs modalg_7 bug28131 (see 0028131). The current version of the test calls fixshape to fix the result shape, and this leads to increasing of the tolerance.|
It is needed to investigate why the result is invalid.
|Tags||No tags attached.|
|Test case number|
|Attached Files||surf_and_offset.png (41,481 bytes) 2017-09-15 12:15|
Investigation revealed that the input b-spline surface has such properties near the degeneracy that its offset has "corrupted" degeneracy. Please see the attached snapshot surf_and_offset.png. The degeneracy point is shifted from the corner of the surface along one of boundary to the inside. At this, the place between the corner and degeneracy behaves like a "black hole" - there is difficult to find a parameters (u,v) to hit into this area.
The offset algorithm creates an edge to cover this part of boundary, and this edge is not degenerated. However, the correspondence of 3D curve and p-curve cannot be fulfilled, and the edge is reported to have invalid curve on surface.
In the scope of this issue it is needed to modify the offset algorithm so that to provide setting to the edge the enough tolerance to cover the same-parameter error.
|2017-08-28 10:14||msv||New Issue|
|2017-08-28 10:14||msv||Assigned To||=> msv|
|2017-08-28 10:14||msv||Status||new => assigned|
|2017-08-28 10:14||msv||Relationship added||related to 0028131|
|2017-08-28 10:27||msv||Summary||BRepOffset_MakeOffset produces invalid shape in test bugs modalg bug28131 => BRepOffset_MakeOffset produces invalid shape in test bugs modalg_7 bug28131|
|2017-08-28 10:27||msv||Description Updated||View Revisions|
|2017-09-15 12:15||msv||Note Added: 0070578|
|2017-09-15 12:15||msv||File Added: surf_and_offset.png|
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