0026816: Boolean operation produces invalid shape in "bugs modalg_5 bug25838" test case - MantisBT

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ID

Project

Category

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Date Submitted

Last Update

0026816

Open CASCADE

[OCCT] OCCT:Modeling Algorithms

public

2015-10-27 11:55

2020-09-14 22:56

Reporter

nbv

Assigned To

msv

Priority

normal

Severity

minor

Status

new

Resolution

open

Platform

OS

OS Version

Product Version

Target Version

[OCCT] 7.6.0*

Fixed in Version

Summary

0026816: Boolean operation produces invalid shape in "bugs modalg_5 bug25838" test case

Description

This bug has been detected while fixing bug 0026675 and is not reproduced on the current MASTER (before fixing bug 0026675).

The main reason is incorrect processing near located edges.

-------------------------------------------------------------------
Try the following script for reproducing:

Draw[]> restore [locate_data_file bug25715_p02c3s1.brep] b1
Draw[]> restore [locate_data_file bug25838_p02c3s2.brep] b2
Draw[]> restore [locate_data_file bug25715_p02c3s3.brep] b3
Draw[]> bfuse b1 b1 b2
Draw[]> don b1 b3
Draw[]> explode b1 f
Draw[]> explode b3 f
Draw[]> donly b1_1 b1_9 b3_1
Draw[]> bopcurves b1_9 b3_1 -2d
#c_1 (c2d1_1, c2d2_1): Tolerance Reached=9.9999999999999995e-008 (FIX) and 2.0504059305500661e-005 (MASTER)

Draw[]> copy c_1 c91

Draw[]> bopcurves b1_1 b3_1 -2d
#c_1...c_5: Tolerance Reached=3.3301015655500105e-007 (FIX) and 4.1550546180586178e-006 (MASTER)

I.e. tolerance for FIX is 3.3301015655500105e-007 + 9.9999999999999995e-008 = 4.3301015655500105e-007.
Tolerance for MASTER is: 2.0504059305500661e-005 + 4.1550546180586178e-006 = 2.4659113923559279e-005.

Draw[]> mkedge ee c_3
Draw[]> donly c91 ee
Draw[]> fit

## SCRIPT 1 (begin)
for {set tpar 0.0} {$tpar <= 1.0} {set tpar [expr $tpar+0.1]} {
  cvalue c91 $tpar xx yy zz
  vertex vv xx yy zz
  distmini dd vv ee

  puts "$tpar : [dval dd_val]"
}
## SCRIPT 1 (end)

## OUTPUT on FIX (begin)

0.0 : 1.5692362877956714e-006
0.1 : 1.5585313640849257e-006
0.2 : 1.5491703735376827e-006
0.30000000000000004 : 1.5420205615884738e-006
0.4 : 1.5343386892894957e-006
0.5 : 1.5247160288497738e-006
0.6 : 1.514314941239327e-006
0.7 : 1.5044067252372638e-006
0.7999999999999999 : 1.4953848034815263e-006
0.8999999999999999 : 1.4850157720097117e-006
0.9999999999999999 : 1.4714760274267883e-006

## OUTPUT on FIX (end)

I.e. the distances on FIX are greater than tolerance. Therefore, edges are not shared. However, these edges are shared on MASTER (for the same reason - distances are lower then tolerance because tolerance is greater).

As result:

Draw[]> bfuse result b1 b3
Draw[]> checkshape result
#BRepCheck_IntersectingWires (on FIX) and OK (on MASTER).

Steps To Reproduce

Test bugs modalg_5 bug25838

Tags

No tags attached.

Test case number

bugs modalg_5 bug25838

Relationships

related to

closed

Open CASCADE

Eliminate normalization of coordinates in ApproxInt package

Notes
(0048540) msv (developer) 2015-11-24 19:59	I have analyzed this case more deeply. The faces b1_1 and b1_9 from the script are built on parallel cylinders. Their axes have distance 1e-6 from each other. It leads to the fact that near the place of interest the surfaces have distance about 7e-7. It is greater than tolerances of shapes (1e-7). After intersection of these faces by the spherical surface the distance between intersection curves is about the same value 7e-7. However, in master version the reached tolerance is much greater (2e-5) and covers the distance. In fix version the intersection curves are computed more precise with the reached tolerance 3e-7, which does not cover the gap between curves. So, the fix works more precise. Taking into account the distance between original nearly-same-domain faces (1e-6), the Boolean operation can work in this case only with help of Fuzzy option. In master version this role was successfully played by roughly computed intersection. I propose to add fuzzy value 1e-6 in this test case to make it theoretically correct.

(0069394) mkv (tester) 2017-08-15 14:45	Problem described in issue is reproduced on current state of OCCT.

Issue History
Date Modified	Username	Field	Change
2015-10-27 11:55	nbv	New Issue
2015-10-27 11:55	nbv	Assigned To	=> msv
2015-10-27 12:07	nbv	Relationship added	related to 0026675
2015-10-27 14:03	nbv	Steps to Reproduce Updated	View Revisions
2015-10-27 15:39	nbv	Description Updated	View Revisions
2015-10-27 15:39	nbv	Steps to Reproduce Updated	View Revisions
2015-10-28 17:31	msv	Target Version	7.0.0 => 7.1.0
2015-11-24 18:01	nbv	Description Updated	View Revisions
2015-11-24 19:59	msv	Note Added: 0048540
2015-11-25 19:18	msv	Relationship added	related to 0025838
2016-10-28 17:03	msv	Target Version	7.1.0 => 7.2.0
2017-07-24 09:22	msv	Target Version	7.2.0 => 7.3.0
2017-08-15 14:45	mkv	Test case number	=> bugs modalg_5 bug25838
2017-08-15 14:45	mkv	Note Added: 0069394
2017-12-05 17:00	msv	Target Version	7.3.0 => 7.4.0
2019-08-12 16:43	msv	Target Version	7.4.0 => 7.5.0
2020-09-14 22:56	msv	Target Version	7.5.0 => 7.6.0*

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