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IDProjectCategoryView StatusDate SubmittedLast Update
0030158CommunityOCCT:Shape Healingpublic2018-09-24 13:342021-11-26 10:09
Reporterdenix56 Assigned Tobugmaster  
PrioritynormalSeverityminor 
Status closedResolutionfixed 
PlatformWindowsOSVC++ 2015 
Product Version7.3.0 
Target Version7.4.0Fixed in Version7.4.0 
Summary0030158: Shape Healing - Incorrect result produced by ShapeUpgrade_UnifySameDomain
DescriptionThe problem is caused by the process of shape fixing in 4 front faces, that has one edge as a seam. Firstly, the left pair of faces is merged and their right edges that are seams are adjusted to form closed wire. Then the right pair merged and again the adjustment is performed and it cracks the previous wire.

I propose not to merge such kind of faces (as ocad performs if the common edge of faces is seam).

The patch and examples of bodies are attached.
Steps To Reproducetest bugs modalg_7 bug30158_1
test bugs modalg_7 bug30158_2
TagsNo tags attached.
Test case numberNot required

Attached Files

  • ShapeUpgrade_UnifySameDomain.cxx.patch (1,902 bytes)
  • shape_after.brep (30,129 bytes)
  • shape2.brep (16,031 bytes)
  • 2_faces.PNG (7,473 bytes)
  • 2_faces_vori_1.PNG (9,186 bytes)
  • 2_faces_vori_4.PNG (8,867 bytes)
  • 2_faces_pcurves_1.PNG (4,783 bytes)
  • 2_faces_pcurves_4.PNG (4,104 bytes)
  • bug30158_1.brep (30,145 bytes)
  • bug30158_2.brep (32,090 bytes)

Relationships

duplicate of 0029504 closedbugmaster Open CASCADE ShapeUpgrade_UnifySameDomain produces invalid shape and ShapeFix_Shape is unable to fix it 

Activities

denix56

2018-09-24 13:34

reporter  

ShapeUpgrade_UnifySameDomain.cxx.patch (1,902 bytes)

denix56

2018-09-24 13:34

reporter  

shape_after.brep (30,129 bytes)

msv

2018-09-24 19:55

developer   ~0079377

I dislike this patch, because it limits the capabilities of the algorithm.

Indeed, the problem here is concluded in the following. The edge common between two faces lying on the same surface must have a special curve representation on that surface allowing specification of two p-curves (BRep_CurveOnClosedSurface).

Now the algorithm makes each face independently, and for this edge the simple curve representation is set (BRep_CurveOnSurface).

So, the solution is to perform postprocessing on the result shape, so as to find such edges and to replace their curve representation with the correct one.

msv

2018-09-24 19:59

developer   ~0079378

The bug 0029504 describes exactly the same problem.

denix56

2018-09-26 10:54

reporter   ~0079406

I have investigated the problem a bit and found out that (in my case) the edge has BRep_CurveOnClosedSurface but int both faces edge is reversed, meaning that it use same 2d curve.
I you know how to integrate face reverse in unify domain, please tell, because I tried different apporaches but the result is incorrect.

msv

2018-09-26 16:13

developer   ~0079414

May be you see in the edge BRep_CurveOnClosedSurface that is left from the old surface, but the algorithm for the new face inserts one more BRep_CurveOnSurface. I saw in your model exactly this issue. The edge in the result has one extra curve representation.
I did not observe non-coherent faces orientation there.

denix56

2018-09-26 20:08

reporter   ~0079419

I tried to add this code:

if(!sff.Status(ShapeExtend_FAIL))
      {
          aResult = sff.Face();

          ShapeBuild_ReShape sbrs;

          for(TopExp_Explorer exp(aResult, TopAbs_WIRE); exp.More(); exp.Next())
          {
              ShapeFix_Wire sfw(TopoDS::Wire(exp.Current()), aResult, Precision::Confusion());
              if(mySafeInputMode)
                  sfw.SetContext(myContext);
              sfw.FixAddPCurveMode() = true;
              sfw.FixEdgeCurves();

              sbrs.Replace(exp.Current(), sfw.Wire());
          }

          aResult = TopoDS::Face(sbrs.Apply(aResult));
        // perform substitution of faces

        myContext->Merge(faces, aResult);
      }

It seems to me that, as I mentioned before the problem is that edge is reversed in both faces, meaning that both faces use same 2d curve from curve_onclosedsurface.

msv

2018-09-26 22:07

developer   ~0079420

How did you find that edge has the same orientation in both faces? If we speak about the attached shape_before.brep then I have checked, and in both the input shape and the result of unification all common edges of concerned faces have different orientation in adjacent faces. Look at draw commands with output:

restore shape_before.brep a
unifysamedom r a

explode a f
explode a_1 e
explode a_5 e
explode a_2 e
explode a_8 e
whatis a_1_4 a_5_1
#a_1_4 is a shape EDGE REVERSED Modified Orientable
#a_5_1 is a shape EDGE FORWARD Modified Orientable
whatis a_2_4 a_8_1
#a_2_4 is a shape EDGE REVERSED Modified Orientable
#a_8_1 is a shape EDGE FORWARD Modified Orientable

explode r f
explode r_1 e
explode r_4 e
whatis r_1_3 r_4_1
#r_1_3 is a shape EDGE FORWARD Modified Orientable
#r_4_1 is a shape EDGE REVERSED Modified Orientable

msv

2018-09-26 22:13

developer   ~0079421

So, my first note 0030158:0079377 is left in force.

I think that such fix is to be done by FixShape algorithm. Now it misses such fix. So, the best way to solve the problem is to add new kind of fix to ShapeFix, and then call the fix from UnifySameDomain on the final result of the algorithm.

denix56

2018-09-27 11:39

reporter   ~0079435

It seems I misunderstand something.
I`ve attached file after performing such fix and fixshifting after that. But the face is still incorrect. Could you please check that shape as you done before?

msv

2018-09-28 11:08

developer   ~0079466

The new shape.brep looks to be valid:
Draw[1]> rest shape.brep r
r
Draw[3]> checksh r
This shape seems to be valid

I have checked the faces and edges deeper, and found out no problem. The edge now has the only curve on closed surface representation, and the face is closed in parameteric space.
How did you obtain such result? Can we add such fix in the code of UnifySameDomain?

denix56

2018-09-28 18:07

reporter   ~0079494

This fix does not fixed the face and when you perform brepcheck on faces it would be unorientable. I am convinced that problem is in the fact that common edge is reversed in both faces, and fix shifted will break it as before.

denix56

2018-10-04 08:44

reporter   ~0079663

Try to perform check on each face of the shape, maybe ut will show problems that occur.

msv

2018-10-05 18:48

developer   ~0079737

I have checked it twice, it is valid, no invalid faces in it. Which OCCT version do you use?

denix56

2018-10-16 15:59

reporter   ~0080019

Last edited: 2018-10-16 16:01

 Sorry, it seems that i provide not the shape that has a problem. Saved wrong one.
Here is one that has holes instead of faces

denix56

2018-10-16 15:59

reporter  

shape2.brep (16,031 bytes)

msv

2019-06-21 17:46

developer  

2_faces.PNG (7,473 bytes)

msv

2019-06-21 17:46

developer  

2_faces_vori_1.PNG (9,186 bytes)

msv

2019-06-21 17:47

developer  

2_faces_vori_4.PNG (8,867 bytes)

msv

2019-06-21 17:47

developer  

2_faces_pcurves_1.PNG (4,783 bytes)

msv

2019-06-21 17:47

developer  

2_faces_pcurves_4.PNG (4,104 bytes)

msv

2019-06-21 17:57

developer   ~0085209

Sorry for long delay.
I have inspected the shape2.brep. It is invalid according to checkshape. And it is correct information.
I have uploaded several screenshots to show what is incorrect in this shape.
The picture 2_faces.PNG shows two faces a_1 and a_4 built on the same cylinder in 3D space view.
The picture 2_faces_vori_1.PNG shows these faces, but the face a_1 is shown with orientations of its edges. The common edge is forward.
The picture 2_faces_vori_4.PNG shows the same, but the face a_4 is shown with orientations. The common edge is reversed.
The picture 2_faces_pcurves_1.PNG shows pcurves of a_1 in 2D space. We see that one edge is shifted in the right direction.
The picture 2_faces_pcurves_4.PNG shows pcurves of a_4. We see the same pcurve of the seam edge is used here but with another edge orientation.

This proves the conclusion I have made in the note 0030158:0079377.

jgv

2019-06-27 13:19

developer  

bug30158_1.brep (30,145 bytes)

jgv

2019-06-27 13:19

developer  

bug30158_2.brep (32,090 bytes)

msv

2019-08-12 17:36

developer   ~0086206

This bug is fixed with #30534. Please close it.

Issue History

Date Modified Username Field Change
2018-09-24 13:34 denix56 New Issue
2018-09-24 13:34 denix56 Assigned To => kgv
2018-09-24 13:34 denix56 File Added: ShapeUpgrade_UnifySameDomain.cxx.patch
2018-09-24 13:34 denix56 File Added: shape_before.brep
2018-09-24 13:34 denix56 File Added: shape_after.brep
2018-09-24 13:39 kgv Assigned To kgv => gka
2018-09-24 13:39 kgv Summary Incorrect result produced by ShapeUpgrade_UnifySameDomain => Shape Healing - Incorrect result produced by ShapeUpgrade_UnifySameDomain
2018-09-24 14:10 abv Assigned To gka => msv
2018-09-24 19:55 msv Note Added: 0079377
2018-09-24 19:59 msv Relationship added duplicate of 0029504
2018-09-24 19:59 msv Note Added: 0079378
2018-09-26 10:54 denix56 Note Added: 0079406
2018-09-26 16:13 msv Note Added: 0079414
2018-09-26 20:08 denix56 Note Added: 0079419
2018-09-26 22:07 msv Note Added: 0079420
2018-09-26 22:13 msv Note Added: 0079421
2018-09-27 11:36 denix56 File Added: shape.brep
2018-09-27 11:39 denix56 Note Added: 0079435
2018-09-28 11:08 msv Note Added: 0079466
2018-09-28 18:07 denix56 Note Added: 0079494
2018-10-04 08:44 denix56 Note Added: 0079663
2018-10-05 18:48 msv Note Added: 0079737
2018-10-16 15:59 denix56 Note Added: 0080019
2018-10-16 15:59 denix56 File Added: shape2.brep
2018-10-16 16:01 denix56 Note Edited: 0080019
2018-10-19 20:26 denix56 Tag Attached: ShapeUpgrade_UnifySameDomain
2019-06-21 17:46 msv File Added: 2_faces.PNG
2019-06-21 17:46 msv File Added: 2_faces_vori_1.PNG
2019-06-21 17:47 msv File Added: 2_faces_vori_4.PNG
2019-06-21 17:47 msv File Added: 2_faces_pcurves_1.PNG
2019-06-21 17:47 msv File Added: 2_faces_pcurves_4.PNG
2019-06-21 17:57 msv Note Added: 0085209
2019-06-27 13:18 jgv File Deleted: shape_before.brep
2019-06-27 13:18 jgv File Deleted: shape.brep
2019-06-27 13:19 jgv File Added: bug30158_1.brep
2019-06-27 13:19 jgv File Added: bug30158_2.brep
2019-08-12 17:36 msv Note Added: 0086206
2019-08-12 17:36 msv Assigned To msv => bugmaster
2019-08-12 17:36 msv Status new => feedback
2019-08-12 17:36 msv Steps to Reproduce Updated
2019-08-13 16:31 bugmaster Test case number => Not required
2019-08-13 16:31 bugmaster Status feedback => verified
2019-08-13 16:31 bugmaster Resolution open => fixed
2019-10-21 13:57 abv Target Version => 7.4.0
2021-11-26 10:09 kgv Tag Detached: ShapeUpgrade_UnifySameDomain