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IDProjectCategoryView StatusLast Update
0023999CommunityOCCT:Modeling Algorithmspublic2014-02-12 13:31
Reportershlkl99 Assigned Toifv 
Status assignedResolutionopen 
Product Version6.6.0 
Summary0023999: Error in BRepAlgoAPI_Section to compute the intersect line between two faces
DescriptionRecently, we worked on a program that used BRepAlgoAPI_Section to compute the intersect line between two faces.

And then, transfer the intersect line to bspline curve.

We used like this:

BRepAlgoAPI_Section sec(m_Face1,m_Face2,PerformNow);

  TopoShape = sec.Shape();
  if (!TopoShape.IsNull())

   TopExp_Explorer ex_Edge;
   for (ex_Edge.Init(TopoShape,TopAbs_EDGE);ex_Edge.More();ex_Edge.Next())

    Standard_Real Frist,Last;
    TopoDS_Edge m_Edge = TopoDS::Edge(ex_Edge.Current());
    Handle(Geom_Curve) bCurve = BRep_Tool::Curve(m_Edge,Frist,Last);
    Handle(Geom_TrimmedCurve) TrimmedCurve = new Geom_TrimmedCurve(bCurve,Frist,Last);
    Handle(Geom_BSplineCurve) m_BSplineCurve = GeomConvert::CurveToBSplineCurve(TrimmedCurve);




The faces we used are attached in attachment(surface2 and surface3).

But we find an error:

if we use opencascade to display the intersect line ,that is OK,like intersectline.igs(attachment)
but if we display in heekscad or UG or other cad software.
it is wrong,the intersect line have a part of a straight line more than before,
you can just try using heekscad.
Steps To Reproduce1. read the file in attachment:surface2 and surface3.
2. using the code i have posted and make intersect
3. export the intersect line (ex:iges file)
4. read in any 3d software(UG,heekscad,ICEM and so on)
5. you can find the error in the intersect line
Additional information
and documentation updates
I think it may be the problem of BRepAlgoAPI_Section
and also this alogrithm is realy slow ,Is any alogrithm faster than BRepAlgoAPI_Section ?
TagsNo tags attached.
Test case numberNot needed

Attached Files

  • sufaces-intersectline.rar (506,776 bytes)



2013-05-28 15:36


sufaces-intersectline.rar (506,776 bytes)


2014-01-29 17:16

administrator   ~0027694

Test case required to check issue.


2014-02-12 13:30

administrator   ~0027856

It's impossible to create test case is our testing system (only display intersect line in other 3d software and see is it OK or BAD).

Issue History

Date Modified Username Field Change
2013-05-28 15:36 shlkl99 New Issue
2013-05-28 15:36 shlkl99 Assigned To => ifv
2013-05-28 15:36 shlkl99 File Added: sufaces-intersectline.rar
2014-01-29 17:16 bugmaster Note Added: 0027694
2014-01-29 17:16 bugmaster Assigned To ifv => apn
2014-01-29 17:16 bugmaster Status new => assigned
2014-02-12 13:30 apn Note Added: 0027856
2014-02-12 13:31 apn Test case number => Not needed
2014-02-12 13:31 apn Assigned To apn => ifv