[vtkusers] using vtkClipClosedSurface() on a box crashes

kent myers dakota_63124 at yahoo.com
Mon May 25 20:23:29 EDT 2015


Hi David,
I did display the box successfully.  This method was extracted from a complete demo  application that I submitted to the bug tracker as issue 0015487.  I have attached it here if you want to look at it.  This would not be the first time that the Java API crashes using methods that work in other languages.
You said it ran without errors.  Did you get a properly clipped box as a result?  It started out as a cube and I put the clipping plane half the height of the cube.
Thanks for taking a look.
Kent

 


     On Monday, May 25, 2015 5:09 PM, David Gobbi [via VTK] <ml-node+s1045678n5731996h29 at n5.nabble.com> wrote:
   

 Hi Kent,
Your code for building the polydata looks suspicious.  If you put your box polydata directly into the mapper (i.e. without vtkClipClosedSurface) does it display properly? 
I translated your code into python (I'm not much of a Java programmer), and it ran without any errors:

from vtk import *
points = [  0.0, 0.0, 0.0,  1.0, 0.0, 0.0,  1.0, 1.0, 0.0,  0.0, 1.0, 0.0,  0.0, 0.0, 1.0,  1.0, 0.0, 1.0,  1.0, 1.0, 1.0,  0.0, 1.0, 1.0,]
seq = [  4, 0,1,2,3,  4, 1,5,6,2,  4, 5,4,7,6,  4, 4,0,3,7,  4, 0,1,5,4,  4, 3,2,6,7]
# create a plane for clippingplane = vtkPlane();plane.SetOrigin(0.0, 0.0, 0.5);plane.SetNormal(0, 0, 1);
# create the box from points and sequencepolyData = vtkPolyData();pts = vtkPoints();for i in range(8):    pts.InsertNextPoint(points[i*3:(i+1)*3])polyData.SetPoints(pts);cells = vtkCellArray();for i in range(6):    cells.InsertNextCell(4)    for j in range(1,5):        cells.InsertCellPoint(seq[5*i + j])polyData.SetPolys(cells);
clipClosedSurface = vtkClipClosedSurface();planes = vtkPlaneCollection();planes.AddItem(plane);clipClosedSurface.SetClippingPlanes(planes);clipClosedSurface.AddInputData(polyData);clipClosedSurface.Update();   # THIS CRASHES
clipMapper = vtkDataSetMapper();clipMapper.SetInputConnection(clipClosedSurface.GetOutputPort());
boxActor = vtkActor();boxActor.SetMapper(clipMapper);boxActor.GetProperty().SetColor(0.8900, 0.8100, 0.3400);
ren = vtkRenderer()ren.AddActor(boxActor)
win = vtkRenderWindow()win.AddRenderer(ren)
iren = vtkRenderWindowInteractor()win.SetInteractor(iren)
iren.Initialize()iren.Start()
On Mon, May 25, 2015 at 5:18 PM, kent myers via vtkusers <[hidden email]> wrote:

I am trying to clip a box constructed as a polydata mesh.  I have tried the
vtkClipPolyData class based on the quadric surface example in the following
link, but have not succeeded.

http://www.vtk.org/Wiki/VTK/Examples/Cxx/Meshes/SolidClip

I found the vtkClipClosedSurface class and it seems like exactly what I am
looking for, but I could not find any examples of how to use it.  The code
below shows my attempt.  It crashes when calling the Update() method.
Without that call, I get no visible result.

Any help would be appreciated!

Kent

        private static void createBox() {
                float[] points = {
                                0.0f, 0.0f, 0.0f,
                                1.0f, 0.0f, 0.0f,
                                1.0f, 1.0f, 0.0f,
                                0.0f, 1.0f, 0.0f,
                                0.0f, 0.0f, 1.0f,
                                1.0f, 0.0f, 1.0f,
                                1.0f, 1.0f, 1.0f,
                                0.0f, 1.0f, 1.0f,
                                };
                int[] seq = {
                                4, 0, 1, 2, 3,
                                4, 1,5,6,2,
                                4, 5,4,7,6,
                                4, 4,0,3,7,
                                4, 0,1,5,4,
                                4, 3,2,6,7};


                // create a plane for clipping
                vtkPlane plane = new vtkPlane();
                plane.SetOrigin(0.0, 0.0, 0.5);
                plane.SetNormal(0, 0, 1);

                // create the box from points and sequence
                vtkPolyData polyData = new vtkPolyData();
                vtkPoints vtkPoints = new vtkPoints();
                vtkFloatArray d = new vtkFloatArray();
                d.SetJavaArray(points);
                d.SetNumberOfComponents(3);
                vtkPoints.SetData(d);
                polyData.SetPoints(vtkPoints);
                vtkCellArray vtkCells = new vtkCellArray();
                vtkIdTypeArray array = new vtkIdTypeArray();
                vtkIntArray intArray = new vtkIntArray();
                intArray.SetJavaArray(seq);
                array.DeepCopy(intArray);
                vtkCells.SetCells(seq.length, array);
                polyData.SetPolys(vtkCells);

                vtkClipClosedSurface clipClosedSurface = new vtkClipClosedSurface();
                vtkPlaneCollection planes = new vtkPlaneCollection();
                planes.AddItem(plane);
                clipClosedSurface.SetClippingPlanes(planes);
                clipClosedSurface.AddInputData(polyData);
                clipClosedSurface.Update();   // THIS CRASHES

                vtkDataSetMapper clipMapper = new vtkDataSetMapper();
                clipMapper.SetInputConnection(clipClosedSurface.GetOutputPort());

                boxActor = new vtkActor();
                boxActor.SetMapper(clipMapper);
                boxActor.GetProperty().SetColor(0.8900, 0.8100, 0.3400);

        }



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