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0000564

VTK

(No Category)

public

2004-02-02 05:03

2016-08-12 09:54

Reporter

Sander Niemeijer

Assigned To

Will Schroeder

Priority

normal

Severity

major

Reproducibility

always

Status

closed

Resolution

moved

Platform

OS Version

Product Version

Target Version

Fixed in Version

Summary

0000564: vtkPolyData + vtkCellData + multiple cell types

Description

When using a combination of cell types within a vtkPolyData object (i.e. both vertices, lines, polys, and/or strips) the cell data property of the vtkPolyData object does not get handled properly (there is no fixed relation between the cell ids of the vtkCellData object and the cell ids of the vtkPolyData object). Furthermore, the polydata mappers are also not consistent in how they deal with the CellData of a vtkPolyData object when the cell data is used for coloring information.

The python code below illustrates the problem:
If things would be correct you should see a red triangle, a green line, and a blue bar. But both the vtkPolyDataMapper and vtkPolyDataMapper2D give different results.

-----
import vtk

VTK_LINE = 3
VTK_POLYGON = 7

# initialize polydata object
polydata = vtk.vtkPolyData()
polydata.SetLines(vtk.vtkCellArray())
polydata.SetPolys(vtk.vtkCellArray())

points = vtk.vtkPoints()
# points for poly 1 (triangle)
points.InsertNextPoint(0.2, 0.3, 0)
points.InsertNextPoint(0.4, 0.55, 0)
points.InsertNextPoint(0.2, 0.8, 0)
# points for line 1 (line)
points.InsertNextPoint(0.5, 0.3, 0)
points.InsertNextPoint(0.5, 0.8, 0)
# points for poly 2 (bar)
points.InsertNextPoint(0.6, 0.3, 0)
points.InsertNextPoint(0.8, 0.3, 0)
points.InsertNextPoint(0.8, 0.8, 0)
points.InsertNextPoint(0.6, 0.8, 0)
polydata.SetPoints(points)

# set scalar cell data
colors = vtk.vtkFloatArray()
polydata.GetCellData().SetScalars(colors)

# create poly 1
ids = vtk.vtkIdList()
ids.InsertNextId(0)
ids.InsertNextId(1)
ids.InsertNextId(2)
cell = polydata.InsertNextCell(VTK_POLYGON, ids)
# poly 1 should get the first color (red)
colors.InsertTuple1(cell, 0.0)

# create line 1
ids.Reset()
ids.InsertNextId(3)
ids.InsertNextId(4)
cell = polydata.InsertNextCell(VTK_LINE, ids)
# line 1 should get the second color (green)
colors.InsertTuple1(cell, 1.0)

# create poly 2
ids.Reset()
ids.InsertNextId(5)
ids.InsertNextId(6)
ids.InsertNextId(7)
ids.InsertNextId(8)
cell = polydata.InsertNextCell(VTK_POLYGON, ids)
# poly 2 should get the third color (blue)
colors.InsertTuple1(cell, 2.0)

# create reference poly with colors as they should be
refpoly = vtk.vtkPolyData()
refpoly.SetLines(vtk.vtkCellArray())
refpoly.GetCellData().SetScalars(colors)
scalars = refpoly.GetCellData().GetScalars()
print scalars.GetNumberOfTuples()
refpoints = vtk.vtkPoints()
refpoints.InsertNextPoint(0.2, 0.2, 0)
refpoints.InsertNextPoint(0.4, 0.2, 0)
refpoints.InsertNextPoint(0.6, 0.2, 0)
refpoints.InsertNextPoint(0.8, 0.2, 0)
refpoly.SetPoints(refpoints)
ids.Reset()
ids.InsertNextId(0)
ids.InsertNextId(1)
cell = refpoly.InsertNextCell(VTK_LINE, ids)
ids.Reset()
ids.InsertNextId(1)
ids.InsertNextId(2)
cell = refpoly.InsertNextCell(VTK_LINE, ids)
ids.Reset()
ids.InsertNextId(2)
ids.InsertNextId(3)
cell = refpoly.InsertNextCell(VTK_LINE, ids)

# define colors
lut = vtk.vtkLookupTable()
lut.SetNumberOfTableValues(3)
lut.SetTableRange(0, 2)
lut.SetTableValue(0, 1.0, 0.0, 0.0, 1.0) # red
lut.SetTableValue(1, 0.0, 1.0, 0.0, 1.0) # green
lut.SetTableValue(2, 0.0, 0.0, 1.0, 1.0) # blue
lut.Build()

# create mapper and assign colortable
polyMapper = vtk.vtkPolyDataMapper()
polyMapper.SetInput(polydata)
polyMapper.SetScalarModeToUseCellData()
polyMapper.UseLookupTableScalarRangeOn()
polyMapper.SetLookupTable(lut)
coordinate = vtk.vtkCoordinate()
coordinate.SetCoordinateSystemToNormalizedViewport()
polyMapper2D = vtk.vtkPolyDataMapper2D()
polyMapper2D.SetTransformCoordinate(coordinate)
polyMapper2D.SetInput(polydata)
polyMapper2D.SetScalarModeToUseCellData()
polyMapper2D.UseLookupTableScalarRangeOn()
polyMapper2D.SetLookupTable(lut)

# same for the refpoly
refpolyMapper = vtk.vtkPolyDataMapper()
refpolyMapper.SetInput(refpoly)
refpolyMapper.SetScalarModeToUseCellData()
refpolyMapper.UseLookupTableScalarRangeOn()
refpolyMapper.SetLookupTable(lut)
refpolyMapper2D = vtk.vtkPolyDataMapper2D()
refpolyMapper2D.SetTransformCoordinate(coordinate)
refpolyMapper2D.SetInput(refpoly)
refpolyMapper2D.SetScalarModeToUseCellData()
refpolyMapper2D.UseLookupTableScalarRangeOn()
refpolyMapper.SetLookupTable(lut)
refpolyMapper2D.SetLookupTable(lut)

# create actors
polyActor = vtk.vtkActor()
polyActor.SetMapper(polyMapper)
polyActor2D = vtk.vtkActor2D()
polyActor2D.SetMapper(polyMapper2D)
refpolyActor = vtk.vtkActor()
refpolyActor.SetMapper(refpolyMapper)
refpolyActor2D = vtk.vtkActor2D()
refpolyActor2D.SetMapper(refpolyMapper2D)

# create renderers
renderer = vtk.vtkRenderer()
renderer.SetViewport(0, 0, 0.5, 1.0)
renderer.AddActor(polyActor)
renderer.AddActor(refpolyActor)
renderer2D = vtk.vtkRenderer()
renderer2D.SetViewport(0.5, 0.0, 1.0, 1.0)
renderer2D.AddActor(polyActor2D)
renderer2D.AddActor(refpolyActor2D)

# render it
renderWindow = vtk.vtkRenderWindow()
renderWindow.SetSize(600,300)
renderWindow.AddRenderer(renderer)
renderWindow.AddRenderer(renderer2D)
iren = vtk.vtkRenderWindowInteractor()
iren.SetRenderWindow(renderWindow)
renderWindow.Render()
iren.Start()

Issue History
Date Modified	Username	Field	Change
2011-06-16 13:11	Zack Galbreath	Category	=> (No Category)
2016-08-12 09:54	Kitware Robot	Note Added: 0036711
2016-08-12 09:54	Kitware Robot	Status	expired => closed
2016-08-12 09:54	Kitware Robot	Resolution	open => moved

Notes
(0036711) Kitware Robot (administrator) 2016-08-12 09:54	Resolving issue as `moved`. This issue tracker is no longer used. Further discussion of this issue may take place in the current VTK Issues page linked in the banner at the top of this page.

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