[vtkusers] Picking Point Problem

[Andrea Gavana]

Hello NG,

      by using the very nice suggestion from Prabhu, I was able to transform a 
Numeric matrix into a vtkStructuredGrid object and to display it very fast. 
Unfortunately, now I'm facing a more complicated problem. 
      I'm using wxPython together with VTK in order to build a small GUI. Now, 
in order to use wxPython with VTK, I use wxVTKRenderWindow and 
wxVTKRenderWindowInteractor from the VTK 4.2 (VTK/Wrapping/Python/wx) release. 
Everything goes fine, I can interact with my window (even if I always have the 
feeling that wxVTKRenderWindowInteractor is never called, and wxVTKRenderWindow 
is called instead to do interactions...). I can zoom, pan, rotate, transform to 
wireframe, surface, and so on...

BUT, when I try to use the "P" key from the keyboard (I think it is used to 
Pick a point), Python (IDLE, Pythonwin, whatever you prefer) crashes with a 
Window$ message dialog like this (sorry I'm translating the error from italian 
language, so it may not be exactly the same in an english/us computer):

-- ERROR MESSAGE BEGIN --

VTK Reservoir Surface: pythonwin.exe - Application Error (THIS IS THE TITLE)

The instruction "0x02a9749e" has made refernce to the memory "0x0cf30020". The 
memory could not be "read".

Click on OK to terminate the application
Click on Abort to debug the application

-- ERROR MESSAGE END --

I don't know what happens, every time is the same. I would just like to be able 
to pick a point in the 3D grid and show it on a small GUI (like mayavi), but 
using wxPython seems to be not so easy.

I include the code I'm using. In the code, nanna refers to my matrix that 
contains all the coordinates of the 3D grid, while zcentout is an array of 
scalars I use to color my 3D grid.

Does anyone has some suggestion? Even other ideas on how to build my GUI or a 
GUI-point picker are welcome...

Thank you a lot for every suggestion.

# CODE BEGIN

vtk_xyz = vtkpython.vtkFloatArray()
vtk_xyz.SetNumberOfTuples(8*nx*ny*nz)
vtk_xyz.SetNumberOfComponents(3)
vtk_xyz.SetVoidArray(Numeric.ravel(nanna),24*nx*ny*nz,1)

vtk_pts = vtkpython.vtkPoints()
vtk_pts.SetNumberOfPoints(8*nx*ny*nz)
vtk_pts.SetDataTypeToFloat()
vtk_pts.SetData(vtk_xyz)

# create vtk data
a = vtkpython.vtkStructuredGrid()
a.SetDimensions(2*nx, 2*ny, 2*nz)
a.SetPoints(vtk_pts)

# create scalars
vtk_scal = vtkpython.vtkFloatArray()
vtk_scal.SetNumberOfTuples(8*nx*ny*nz)
vtk_scal.SetNumberOfComponents(1)
vtk_scal.SetVoidArray(Numeric.ravel(zcentout),8*nx*ny*nz,1)

a.GetPointData().SetScalars(vtk_scal)

mapsurface = vtkpython.vtkDataSetMapper()
mapedge = vtkpython.vtkDataSetMapper()
meshGeom = vtkpython.vtkExtractGrid()

meshGeom.SetInput(a)

mapsurface.SetInput(meshGeom.GetOutput())
mapedge.SetInput(meshGeom.GetOutput())
	
actsurface = vtkpython.vtkActor()
actsurface.SetMapper(mapsurface)
actedge = vtkpython.vtkActor()
actedge.SetMapper(mapedge)
	
data_range = a.GetScalarRange()
mapsurface.SetScalarRange(data_range)
mapsurface.ScalarVisibilityOn()
mapedge.SetScalarRange(data_range)
mapedge.ScalarVisibilityOff()

actsurface.GetProperty().SetRepresentationToSurface()
actsurface.SetScale(1.0,1.0,6.0)
actsurface.SetOrientation(135.0,0.0,0.0)

actedge.GetProperty().SetRepresentationToWireframe()
actedge.GetProperty().SetLineWidth(1.5)
actedge.SetScale(1.0,1.0,6.0)
actedge.SetOrientation(135.0,0.0,0.0)
actedge.GetProperty().SetColor(0,0,0)
actedge.GetProperty().SetAmbient(1.0);
actedge.GetProperty().SetDiffuse(0.0);
actedge.GetProperty().SetSpecular(0.0);
	
ren = vtkpython.vtkRenderer()

self.window = wxFrame(None, -1, "VTK Reservoir Surface", wxPoint(100,10), 
wxSize518, 282), 
style=wxDEFAULT_FRAME_STYLE|wxRESIZE_BORDER|wxNO_FULL_REPAINT_ON_RESIZE)

hiwin = wxVTKRenderWindow(self.window,-1,1)
hirenWin = hiwin.GetRenderWindow()
hiren = vtkpython.vtkRenderer()
hiren.SetRenderWindow(hirenWin)

hiren.AddActor(actsurface)
hiren.AddActor(actedge)

hirenWin.AddRenderer(hiren)
hiren.GetActiveCamera().Zoom(1.5)
self.window.Show(TRUE)
self.window.SetSize((1000,900))

iren = wxVTKRenderWindowInteractor(self.window, -1,1)
iren.SetRenderWindow(hirenWin)

iren.Initialize()
iren.Start()


# CODE END