Archived issue #0027872

BRepAlgoAPI_Common returns invalid shape

CommunityOCCT:Modeling Algorithmsclosed5 public notes

Description

For the appended case (Boolean common of a solid and a shell) the result in OCCT 7.0.0 is invalid. In OCCT 6.9.1 the result was valid and as expected.

The arguments of the Boolean operation are valid.

Steps to reproduce

pload ALL

restore Attachment 1 (BREP) e

whatis e

explode e

whatis e_1

whatis e_2

vinit

vdisplay e_1

vdisplay e_2

vfit

bopcheck e_1

bopcheck e_2

bopargcheck e_1 e_2 -O #F

bop e_1 e_2

bopcommon r

whatis r

explode r

whatis r_1

vdisplay r_1

checkshape r_1
# In OCC 7.0.0:
# On Shape faulty_1 :
# BRepCheck_UnorientableShape
# Shape faulty_2 on shape faulty_1 :
# BRepCheck_NotClosed

bopcheck r_1

Public activity

5 archived notes

Participants are labeled by their role within this record.

01Commenter 12016-09-14 17:02

Looking at result shape in 7.0 (and current dev) version and in 6.9.1, we can see that in the current version the result form is right, while in 6.9.1 the result form repeats the shape e_2, and this is incorrect.
So, this is not a regression, because result in 7.0 is better.
I confirm that checkshape reports faulties, and this is a bug, but it is not a regression to 6.9.1.

02Author2016-09-14 17:13

Yes, you are right.

03Commenter 32016-09-14 17:22

The surface of the face e_2_1 has a fold, which is the cause of the fault. Please, see the attached picture that shows the fragment of v-isoline of that surface at parameter v=0.45688124426104931, u is between [0.17,0.225]. You can see this fold via this isoline. The extent of the fold is about 1e-4. Due to this fold, the intersection algorithm gives disconnected intersection line, and this leads to unclosed wire on face.

04Author2016-09-15 12:34

OK, thanks.
Then the issue could be closed.

05Commenter 52016-09-15 12:46

Dear Commenter 1, please close this bug.