[vtkusers] Problems with scalar contours

[Daniel Rypl]

Dear Vtk users,

is it correct that when applying color to a vtkActor as

vtkActor meshActor
   meshActor SetMapper meshMapper
   [meshActor GetProperty] SetColor 1 0 0

then the scalar contours (defined together with an unstructured
grid in vtk DataFile Version 2.0) are made in that color only
(red in this case) ?

The problem is that I do not know in advance that scalar values
are present in the data file and I still want to use the same Tcl script.
When using without color assigment, scalar contours are OK but
if there are no scalars in data file, the drawing is white (of course).


I am using Vtk 4.2 on Linux RedHat 9 with Mesa 4 and Tcl/Tk 8.3.
It was working fine on Vtk 3.1 RedHat 5.2.

Could anyone advise me?

Thanks a lot for any help

Daniel Rypl


PS: Below is the Vtk data file and Tcl script. Should you be so kind


PS: Below is the Vtk data file and Tcl script. Should you be so kind
    and try it running using your vtk, please save the Vtk data file
    as m.vtk.

=========================================================================
# vtk DataFile Version 2.0
# simple example
ASCII
DATASET UNSTRUCTURED_GRID
POINTS 4 float
1 1 0
2 1 0
1 2 0
2 2 0
CELLS 6 16
1 0
1 1
1 2
1 3
3 0 1 2
3 1 3 2
CELL_TYPES 6
1
1
1
1
5
5
POINT_DATA 4
SCALARS sample_scalars float
LOOKUP_TABLE my_table
0.0
1.0
2.0
3.0
LOOKUP_TABLE my_table 3
1.0 0.0 0.0 1.0
0.0 1.0 0.0 1.0
0.0 0.0 1.0 1.0




==========================================================================
#package require vtk
package require vtkinteraction

# Display unstructured mesh

set inputFileName m.vtk

# Create renderer stuff
#
vtkRenderer ren1
vtkRenderWindow renWin
   renWin AddRenderer ren1
vtkRenderWindowInteractor iren
   iren SetRenderWindow renWin

# create pipeline
#
vtkUnstructuredGridReader geometryReader;
   geometryReader SetFileName $inputFileName

vtkDataSetMapper meshMapper
   meshMapper SetInput [geometryReader GetOutput]
   meshMapper ScalarVisibilityOn
   meshMapper SetScalarRange -0.00001 3.00001

vtkActor meshActor
   meshActor SetMapper meshMapper
#
## Comment the following line to see scalar contours
#
   [meshActor GetProperty] SetColor 1 0 0

vtkAxes meshAxesSource
   meshAxesSource SetScaleFactor 1
   meshAxesSource SetOrigin 0 0 0

vtkPolyDataMapper meshAxesMapper
   meshAxesMapper SetInput [meshAxesSource GetOutput]

vtkActor meshAxes
   meshAxes SetMapper meshAxesMapper

ren1 AddActor meshAxes
meshAxes VisibilityOff

# Add the actors to the renderer, set the background and size
#
ren1 AddActor meshActor
ren1 SetBackground 0.1 0.2 0.4
renWin SetSize 640 480
[ren1 GetActiveCamera] SetPosition 0 0 10
[ren1 GetActiveCamera] Azimuth 0
[ren1 GetActiveCamera] Dolly 1.4
ren1 ResetCameraClippingRange

meshAxes VisibilityOn
renWin Render

iren AddObserver UserEvent {wm deiconify .vtkInteract}

# prevent the tk window from showing up then start the event loop
#
wm withdraw .