[vtkusers] vtkPointPicker

[Sarah Graham]

I am using vtkPointPicker to select points on a surface.  Once selected, I
am placing a small sphere in that location as a marker.  I am having
problems with the model interaction in this process.

The process of placing markers works fine if I only pick points and do not
use the mouse buttons to interact with the model. (i.e. rotate the model)
In addition, the model interaction works fine before I add any spherical
markers. (created using multiple sphereActors)  However, if I try to
interact with the model after placing one or more spherical markers, the
program crashes.

To handle the point picking, I define a PickerHandler method and call
iren->SetPickerHandlerMethod(PickerHandler...).  Inside PickerHandler, I
create a new sphereActor each time a valid point is picked and add that
actor to the renderer.  

So...2 questions:
1) Any idea why the program is crashing when I try to add markers and then
move the model.
2) Is there a better way to add multiple spherical markers other than
creating a new sphereActor each time?

Thanks,
-Sarah

------------------------
Sarah Graham
Johns Hopkins University
sarah at cs.jhu.edu
http://www.sarahgraham.org