[vtkusers] what kind input data does vtkstreamline need?

[Zhao Yongqiang]

Hi all,
       After i get the segmented data, i use marching cube to visualize 
the blood vessel. Then,  I want to use vtkstreamline to simulate blood 
flow. But when i use the output of the marching cube as the input of 
vtkstreamline , it said that "No vector data defined!".
      Can someone tell me the reason? and how to solve it?
      Thanks in advance!


Zhao Yongqiang
2005.5.16