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0026311Open CASCADE[OCCT] OCCT:Modeling Algorithmspublic2015-06-04 10:252015-06-04 11:19
[OCCT] Unscheduled 
0026311: Add check in Param-Param-intersection algorithm if surfaces are coincided or if thay do not have any intersection
If surfaces are coincided then there is no point in returning any intersection curve (see bug #26151).

If surfaces do not have any intersection the intersection algorithm will return empty result. However, processing this case takes too much time. Therefore, it will be better to detect this case before calling intersection algorithm (creating Walking-line).
1. Example of coinciding surfaces:
  1.1. See Steps To Reproduce for bug #26151.
  1.2. Modified test case bugs\modalg_2\bug23732:

restore [locate_data_file bug23732_fx1.brep] b1
restore [locate_data_file bug23732_fx2.brep] b2

mksurface s1 b1
mksurface s2 b1

intersect result s1 s2

2. Example of not-intersecting surfaces:
  2.1. See message [^] offset faces_type_i C8, offset faces_type_i D7, offset shape_type_i C8, offset shape_type_i D6, offset shape_type_i D7.
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zip (28,127) 2015-06-04 10:38
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Issue History
2015-06-04 10:25nbvNew Issue
2015-06-04 10:25nbvAssigned To => msv
2015-06-04 10:38nbvFile Added:
2015-06-04 10:38nbvFile Added:
2015-06-04 11:15nbvNote Added: 0041929
2015-06-04 11:18nbvFile Deleted:
2015-06-04 11:19nbvFile Added:
2015-06-04 11:19nbvRelationship addedrelated to 0026151

2015-06-04 11:15   
One of idea to detect not-intersecting surfaces is that the Surface-Surface extrema should be used before intersection calling. It is enough to find only one minimum (there is no point in finding every extrema). If this minimal distance is greater, than tolerance, surfaces are not intersected. Nevertheless, what about performance?