Hello and happy new year to everyone,
I’m trying to import some triangulated surfaces DEMs (digital elevation models) from a csv file to vtk. I have no problem importing the file and creating the triangles in VTK, I also wanted to add a colormap for elevation. I managed to add the scalar values and it automatically creates a black and white colormap if i set the scalars with a range from 0 to 255. But somehow I cannot manage to change any properties of this automatic LookUpTable that is being created.
Here is the code to create the triangulates surface (with zcolor set to True):
def tri2poly(tri,zcolor=False):
#setup points and vertices
Points = vtk.vtkPoints()
Triangles = vtk.vtkCellArray()
#puntos de los vertices del primer triangulo
if zcolor:
Zs=[]
min=float('inf')
max=float('-inf')
for vert in tri:
for i in range(0,3):
Points.InsertNextPoint(vert[i])
if zcolor:
z=vert[i][2]
Zs.append(z)
if z<min: min=z
if z>max: max=z
if zcolor:
Colors = vtk.vtkUnsignedCharArray()
Colors.SetNumberOfComponents(1)
Colors.SetName("Colors")
Zs_norm=[255*(z-min)/(max-min) for z in Zs]
for i in range(0,len(tri)):
Triangle = vtk.vtkTriangle()
Triangle.GetPointIds().SetId(0, i*3)
Triangle.GetPointIds().SetId(1, i*3+1)
Triangle.GetPointIds().SetId(2, i*3+2)
Triangles.InsertNextCell(Triangle)
if zcolor:
Colors.InsertNextTuple1(Zs_norm[i*3])
Colors.InsertNextTuple1(Zs_norm[i*3+1])
Colors.InsertNextTuple1(Zs_norm[i*3+2])
#create polydata and add triangles
polydata = vtk.vtkPolyData()
polydata.SetPoints(Points)
polydata.SetPolys(Triangles)
if zcolor:
#ingresar los datos de los atributos
polydata.GetPointData().AddArray(Colors)
#definir cual atributo define el color por default
polydata.GetPointData().SetActiveScalars("Colors")
return polydata
And here is the code to plot the data. For some reason, it simple wont respond to any changes in the lut settings. I can skip the lut altogether and it will always display the same black and white colorbar. Set scalarRange doesnt seem to change anything either, it always chooses to use 0 to 255.
def plotPolydata(polydata):
colors = vtk.vtkNamedColors()
#This LUT does nothing??
lut=vtk.vtkLookupTable()
# lut.SetValueRange(0,255)
# lut.SetSaturationRange(0,1)
lut.SetHueRange(0.667, 1)
lut.Build()
mapper = vtk.vtkPolyDataMapper()
mapper.SetInputData(polydata)
#mapper.ScalarVisibilityOff()
mapper.SetLookupTable(lut)
#mapper.SetScalarRange(0,100)
#mapper.SetScalarRange(polydata.GetScalarRange())
actor = vtk.vtkActor()
actor.SetMapper(mapper)
#actor.GetProperty().SetColor(colors.GetColor3d('Tan'))
# Create a rendering window and renderer
ren = vtk.vtkRenderer()
renWin = vtk.vtkRenderWindow()
renWin.AddRenderer(ren)
renWin.SetWindowName('Preview')
renWin.SetSize(640,480)
# Create a renderwindowinteractor
iren = vtk.vtkRenderWindowInteractor()
iren.SetRenderWindow(renWin)
# Assign actor to the renderer
ren.AddActor(actor)
# Enable user interface interactor
iren.Initialize()
renWin.Render()
ren.SetBackground(colors.GetColor3d('AliceBlue'))
renWin.Render()
iren.Start()
If someone can guide me to solve this problem I would be very grateful.
Cheers,
Ignacio Villalón