[vtkusers] HELP vtkPointPicker question

[xiaofeng qi]

Hi,vtkusers

  I am using vtk+java to develop a application to visualize
some CFD data.I use vtkPointPicker to pick the  point 
from a section plane,then i use the point's coordinate
as start point of a streamline , but something cause me annoyed,
The point's coordinate i got from vtkPointPicker is not
the same  to the start point of the streamline,when I 
press the mouse ,and the streamline do not start from the
cursor'position, it starts from some place else.
here is some of my codes,
     

    vtkPointPicker picker=new vtkPointPicker();
       picker.InitializePickList();
       picker.AddPickList(sectionActor);
       picker.PickFromListOn();
       picker.SetTolerance(0.01);
       picker.Pick(lastX, lastY, 0, renWin.GetRenderer());
      
      
   if(picker.GetPointId()<0){

        System.out.println("Mouse point: ("+lastX+","+lastY+")");
        System.out.println("notok");
         }else{
     
        double []selPt = picker.GetSelectionPoint();
        double []pickPos = picker.GetPickPosition();
	
        drawStreamline(pickPos);
        }
       ..............................
　　　　　　　　
 Do i miss something?Any help will be appreciate.

Thanks !!!

 				

　　　　　　　　xiaofeng qi
　　　　　　　　xiaofeng_qi at sina.com
　　　　　　　　　　2003-10-22