[vtkusers] picking and displaying data points

[Gopalakrishnan, Gowri]

Hi 

i pass (x,y,Z) coordinates and render it and then I add glyph3d to put
points on it which correspond to 
data points. If I use vtkpointpicker->GetPosition it gives me coordiantes in
global coord and if i use 
vtkworkpointpicker it gives me coordinates in world coord. But none of them
are my point position
(the world one is closer to mine)
If i click on the glyphpoint and to get my exact data point what should i
do?
Thanks for any help

Regards
Gowri