[vtkusers] newbie question - drawing a line!

[Anusha]

Hi,

I'm trying to draw lots of raypaths on a 3-D model I've created by 
plotting a lines joining up the multiple points which define these 
paths.  I am sure it is a very trivial thing to do and that I'm making 
a basic mistake somewhere but have been grappling with it for a while 
and but can't seem to to make it work so any help/suggestions would be 
much appreciated!  Am I on the right track - should I be trying to turn 
the set of points into cells or should my data be defined as lines in 
the data file to begin with?

Many thanks!
Anusha


My data set is a set of x,y,z grid points and looks like...

# vtk DataFile Version 2.0
Ray paths
ASCII

DATASET POLYDATA
POINTS 143088 float
21.3300 50.9900 -0.0241
21.3300 50.9900 -0.0241
21.3300 50.9900 -0.0328
21.3300 50.9900 -0.0327
....etc


and this is the chunk of code I've been attempting to make work (but 
get an error when trying to get the output of the vtkPolyData "rays" in 
the vtkPolyDataReader.)



vtkPolyDataReader raysReader
raysReader SetFileName "rays.vtk"

vtkPolyData rays
vtkPoints points
vtkCellArray line

set numPoints [[raysReader GetOutput] GetNumberOfPoints]

for {set i 0 } { $i <  $numPoints} { incr i } {
     set val [[raysReader GetOutput] GetPointData]
     points InsertPoint $i $i $val
}
rays SetPoints points
points Delete

line InsertNextCell $numPoints
for {set i 0 } { $i <  $numPoints} { incr i } {
     line InsertCellPoint $i
     ptIds[1] =
}

rays SetLines line
line Delete


vtkPolyDataMapper mapRays
   mapRays SetInput [rays GetOutput]
vtkActor raysActor
   raysActor SetMapper mapRays