[vtkusers] Re : Re : Holes in mesh after vtkBooleanOperationPolyDataFilter

[Malsoaz James]

Ok I see. Thank you.

Meanwhile, I will try to look at another implementation of boolean operations (something with CSG maybe). I found something on the VTK Journal : http://www.midasjournal.org/browse/publication/726 about the use of GTS for such computations.

Did you try it ?

Best



________________________________
 De : Cory Quammen <cquammen at cs.unc.edu>
À : Malsoaz James <jmalsoaz at yahoo.fr> 
Cc : Bryn Lloyd <lloyd at itis.ethz.ch>; "vtkusers at vtk.org" <vtkusers at vtk.org> 
Envoyé le : Mardi 22 mai 2012 15h18
Objet : Re: [vtkusers] Re : Holes in mesh after vtkBooleanOperationPolyDataFilter
 
There's a known problem when vertices on one of the input surfaces are
within epsilon of a surface-to-surface intersection. It's on my to do
list to make this more robust.

Thank you for providing another example for me to test.

Thanks,
Cory

On Tue, May 22, 2012 at 9:02 AM, Malsoaz James <jmalsoaz at yahoo.fr> wrote:
> Thank you,
>
> I'm gonna try this solution.
>
> Is this problem due to the implementation of the algorithm to compute the
> boolean operation ?
>
> I'm a bit confused, because the holes doesn't appear in a place where there
> are intersections or unions.
>
> I have been trying to use this website : http://evanw.github.com/csg.js/ to
> test another implentation of the CSG and it works even with parallel
> surfaces.
> You can try the following in the text box at the end of the page (note that
> the page requires WebGL) :
>
> var a = CSG.cylinder({radius:0.2, center:[0, 0, 0]});
> var b = CSG.cube({radius:[1, 0.5, 0.2], center:[0, 0, 0]});
> var c = CSG.cylinder({radius:0.2, start: [-1, -1, 0], end: [-1, 1, 0]});
> return a.union(b).union(c);
>
> Best.
>
> ________________________________
> De : Bryn Lloyd <lloyd at itis.ethz.ch>
> À : vtkusers at vtk.org
> Envoyé le : Mardi 22 mai 2012 14h05
> Objet : Re: [vtkusers] Holes in mesh after vtkBooleanOperationPolyDataFilter
>
> The boolean operations are not robust for parallel surfaces.
>
> One way to try to resolve the problem is to move the objects by some small
> delta before applying the boolean operation.
>
>
> On 5/22/2012 11:15 AM, Malsoaz James wrote:
>
> Hi VTK users,
>
> I'm using the vtkBooleanOperationPolyDataFilter to apply boolean operations
> to polydata. Unfortunately, I got unexpected results (holes in the mesh).
>
> You can see here http://www.hostingpics.net/viewer.php?id=210273error.png an
> example.
> I'm creating a cylinder, then I'm adding a cube and finally I'm adding
> another cylinder. The holes appear with the last operation.
>
>
> Can someone explain me the reason(s) of these results ?
>
> Here are my source code :
> vtkCylinderSource * cylinder1 = vtkCylinderSource::New();
> cylinder1->SetCenter(0, 10, 0);
> cylinder1->SetHeight(50);
> cylinder1->SetRadius(5);
> cylinder1->SetResolution(100);
> cylinder1->Update();
>
> vtkTriangleFilter * cylinder1Triangle = vtkTriangleFilter::New();
> cylinder1Triangle->SetInput(cylinder1->GetOutput());
> cylinder1Triangle->Update();
>
> cylinder1->Delete();
>
> vtkCubeSource * cube = vtkCubeSource::New();
> cube->SetCenter(0, 10, 0);
> cube->SetXLength(50);
> cube->SetYLength(20);
> cube->SetZLength(10);
> cube->Update();
>
> vtkTriangleFilter *cubeTriangle = vtkTriangleFilter::New();
> cubeTriangle->SetInput(cube->GetOutput());
> cubeTriangle->Update();
>
> cube->Delete();
>
> vtkCylinderSource * cylinder2 = vtkCylinderSource::New();
> cylinder2->SetCenter(-25, 15, 0);
> cylinder2->SetHeight(30);
> cylinder2->SetRadius(3);
> cylinder2->SetResolution(100);
> cylinder2->Update();
>
> vtkTriangleFilter * cylinder2Triangle = vtkTriangleFilter::New();
> cylinder2Triangle->SetInput(cylinder2->GetOutput());
> cylinder2Triangle->Update();
>
> cylinder2->Delete();
>
> vtkBooleanOperationPolyDataFilter * add1 =
> vtkBooleanOperationPolyDataFilter::New();
> add1->SetOperationToUnion();
> add1->SetInput(0, cylinder1Triangle->GetOutput());
> add1->SetInput(1, cubeTriangle->GetOutput());
> add1->Update();
>
> cubeTriangle->Delete();
> cylinder1Triangle->Delete();
>
> vtkBooleanOperationPolyDataFilter * add =
> vtkBooleanOperationPolyDataFilter::New();
> add->SetOperationToUnion();
> add->SetInput(0, add1->GetOutput());
> add->SetInput(1, cylinder2Triangle->GetOutput());
> add->Update();
>
> add1->Delete();
> cylinder2Triangle->Delete();
>
> Am I doing something wrong in the use of vtkBooleanOperationPolyDataFilter ?
>
> Thank you.
> Best
>
>
> _______________________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at
> http://www.kitware.com/opensource/opensource.html
>
> Please keep messages on-topic and check the VTK FAQ at:
> http://www.vtk.org/Wiki/VTK_FAQ
>
> Follow this link to subscribe/unsubscribe:
> http://www.vtk.org/mailman/listinfo/vtkusers
>
>
> _______________________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at
> http://www.kitware.com/opensource/opensource.html
>
> Please keep messages on-topic and check the VTK FAQ at:
> http://www.vtk.org/Wiki/VTK_FAQ
>
> Follow this link to subscribe/unsubscribe:
> http://www.vtk.org/mailman/listinfo/vtkusers
>
>
>
> _______________________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at
> http://www.kitware.com/opensource/opensource.html
>
> Please keep messages on-topic and check the VTK FAQ at:
> http://www.vtk.org/Wiki/VTK_FAQ
>
> Follow this link to subscribe/unsubscribe:
> http://www.vtk.org/mailman/listinfo/vtkusers
>



-- 
Cory Quammen
Research Associate
Department of Computer Science
The University of North Carolina at Chapel Hill
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.vtk.org/pipermail/vtkusers/attachments/20120522/9fb77e51/attachment.htm>