[vtkusers] associating data to polydata

[Malcolm Drummond]

> this means that I need to tessellate each polygon in a different polydata to keep the link between original objects 
> number and final tessellated objects

No, in your case I don't think you have to. vtkTriangle filter should copy the polygon cell-data to respective triangles, so you'll only need ids plus whatever values you require for visualization in your original polygon cell-data, the rest can be held in the polydata field-data or wherever. I just tried it in the script below with ids in scalars and they're carried through, so you can use these to look into the original field-data. I had a peek at the vtkTriangleFilter source code and it should copy any array in cell-data that doesn't have the copy flag set to off ... or maybe I misunderstand you.

HTH
Malcolm

#-------------------------------------------

from vtk import *
import sys

pts = vtkPoints()
polys = vtkCellArray()
scalars = vtkIntArray()
pd = vtkPolyData()
pd.SetPoints(pts)
pd.SetPolys(polys)
pd.GetCellData().SetScalars(scalars)

scalars.InsertNextValue(0)
scalars.InsertNextValue(1)

pts.InsertNextPoint(-100.0, -50.0, 0.0)
pts.InsertNextPoint(   0.0, -50.0, 0.0)
pts.InsertNextPoint(   0.0,  50.0, 0.0)
pts.InsertNextPoint(-100.0,  50.0, 0.0)
pts.InsertNextPoint( 100.0, -50.0, 0.0)
pts.InsertNextPoint( 100.0,  50.0, 0.0)

# define contour
polys.InsertNextCell(4)
polys.InsertCellPoint(0) 
polys.InsertCellPoint(1) 
polys.InsertCellPoint(2) 
polys.InsertCellPoint(3)
polys.InsertNextCell(4)
polys.InsertCellPoint(1) 
polys.InsertCellPoint(4) 
polys.InsertCellPoint(5) 
polys.InsertCellPoint(2)  

tf = vtkTriangleFilter()
tf.SetInput(pd)

pdm = vtkPolyDataMapper()
pdm.SetInput(tf.GetOutput())

actor = vtkActor()  
actor.SetMapper(pdm)
actor.GetProperty().SetColor(0,0,1)

ren = vtkRenderer()
renwin = vtkRenderWindow()
renwin.AddRenderer(ren)
iren = vtkRenderWindowInteractor()
iren.SetRenderWindow(renwin)

ren.AddActor(actor)
ren.SetBackground(1,1,1)
renwin.SetSize(600,600)

iren.Initialize
renwin.Render()
iren.Start()

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