[vtkusers] vtkCellPicker

[Patrick de Koning]

"David J. Netherway" wrote:
> 
> Hello,
> 
> I am using a daily vtk from August 7, 2000 on winNT.
> 
> >From a single cube source and a single mapper I generate multiple actors
> at different positions.
> 
> I use SetPosition on each actor to position each of them.
> 
> They appear where I expect them.
> 
> Using a cellPicker I can select them and have code to move them around,
> again using SetPosition.
> 
> They move to where I put them using the mouse.
> 
> At this stage they cannot be picked unless I click the mouse at their
> original position.
> 
> Does anyone know of problems relating to cellPicking and repeated use of
> the SetPosition method?
> 

Yes, I know of this problem. When you use SetPosition on the actor, the
points which make up the polydat fro the cube are NOT modified, only the
display coordinates are modified. If you use something like
vtkCubeSource->SetCenter(..) then the points of the polydata are
modified and the cellpicker will work.

I mailed this problem to the list some time ago, but didn't get any
response from Kitware if this is a bug or not.

> I use
> set assembly [[[cellPicker Getpath] GetFirstNode] GetProp]
> to get the actor.
> 
> This is successful for repeated pickings if the actor stays at its first
> location.
> 
> Thanks, David
> 
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-- 
--------------------------------------------------------------------
Ir. P.J.H. de Koning                    Leiden University Medical Center
Department of Radiology, C2S            Division of Image Processing
P.O. Box 9600                           2300 RC  LEIDEN
the Netherlands                         Tel. +31-71-5266206  
Fax +31-71-5266801                      Email patrick at lkeb.azl.nl