View Issue Details
|ID||Project||Category||View Status||Date Submitted||Last Update|
|0023943||Community||OCCT:Modeling Algorithms||public||2013-05-03 18:18||2013-12-19 13:55|
|Reporter||Roman Lygin||Assigned To||Roman Lygin|
|Target Version||6.7.0||Fixed in Version||6.7.0|
|Summary||0023943: OCC fails to work with offset surfaces with singularities|
|Description||Unlike other types of surfaces, offsets throw an exception Geom_UndefinedValue (or _UndefinedDerivative) when trying to compute values near their singularities.|
Therefore algorithms that do not expect surface evaluation to throw exception eventually produce incorrect results when working with such geometries.
The fix addresses two cases trying to improve robustness of OCC:
1. singularity is now recognized in Geom_OscullatingSurface if the derivative is below the tolerance (regardless that it should be greater than 1e-12 threshold used before)
2. ShapeAnalysis_Surface::ValueOf() now avoids going beyond the surface range for offset surfaces.
1. In 0000001 additionally the debug output in Geom_OscullatingSurface.cxx has been suppressed in production version as otherwise it severely contaminates the log.
Suppression is done by adding another macro which could be defined only in OCC development environment. OCC team is free to modify the name as sees fit.
2. In 0000002 it would probably be good to prevent going beyond surface range for all types of (non-periodic?) surfaces. However to minimize fix impact it has been limited to offsets only.
|Steps To Reproduce||See two independent reproducers attached.|
|Tags||No tags attached.|
|Test case number||bugs moddata_3(013) bug23943_1, bug23943_2, bug23943_3, bug23943_4|
rep1.zip (499,784 bytes)
rep2.zip (227,155 bytes)
||The fix pushed to the git repository|
The first part of correction (elimination of TolMin from test of singular point) seems to be Ok.
The second part of correction (ShapeAnalysis_Surface::ValueOf()) can be consider as temporal solution for following reasons:
the going beyond surface domain is not "fatal" problem for practically all types of not periodic surface including offset surface because these surfaces can be analytically extended. Of course, extension must not be too large.
Sometimes going beyong surface happens by "natural" way, for example, while getting pcurve by projection of 3d curve, which is near surface boundary.
Problem of given offset surface is that basis surface is singular and osculating surface is built for Umax, but derivative are calculated for u > Umax. Perhaps, the correct fix of bug must solve problem of extension of osculating surface, if it exists for u > Umax.
So problem requires additional investigations.
Branch CR23943 (and products from GIT master) was compiled on Linux and Windows platforms and tested.
Number of compiler warnings:
occt component :
Linux: 2 (2 on master)
Windows: 11 (11 on master)
products component :
Linux: 0 (0 on master)
Windows: 64 (64 on master)
bugs moddata_3(013) bug23943_1, bug23943_2, bug23943_3, bug23943_4 - OK
Testing on Linux:
Total MEMORY difference: 365857352 / 365850136
Total CPU difference: 41145.37000000122 / 45786.650000001355
Testing on Windows:
Total MEMORY difference: 415969780 / 418014292
Total CPU difference: 38610.796875 / 29305.09375
There are not differences in images found by testdiff.
||Fix has been integrated into master of occt repository|
|2013-05-03 18:18||Roman Lygin||New Issue|
|2013-05-03 18:18||Roman Lygin||Assigned To||=> jgv|
|2013-05-03 18:18||Roman Lygin||File Added: rep1.zip|
|2013-05-03 18:18||Roman Lygin||File Added: rep2.zip|
|2013-05-03 18:25||Roman Lygin||Note Added: 0024308|
|2013-05-03 18:25||Roman Lygin||Status||new => resolved|
|2013-05-06 12:03||jgv||Assigned To||jgv => ifv|
|2013-05-06 18:30||ifv||Note Added: 0024316|
|2013-05-06 18:30||ifv||Status||resolved => reviewed|
||Note Added: 0024481|
||Test case number||=> bugs moddata_3(013) bug23943_1, bug23943_2, bug23943_3, bug23943_4|
||Assigned To||ifv => bugmaster|
||Status||reviewed => tested|
|2013-05-23 12:39||bugmaster||Target Version||=> 6.7.0|
|2013-05-28 14:33||bugmaster||Note Added: 0024534|
|2013-05-28 14:33||bugmaster||Status||tested => verified|
|2013-05-28 14:33||bugmaster||Resolution||open => fixed|
|2013-05-28 14:33||bugmaster||Assigned To||bugmaster => Roman Lygin|
|2013-06-02 15:56||abv||Relationship added||related to 0024008|
|2013-12-19 13:53||bugmaster||Status||verified => closed|
|2013-12-19 13:55||bugmaster||Fixed in Version||=> 6.7.0|