[vtkusers] Polydata filtering in real-time

[Nil Goyette]

While waiting for an answer, I tried coding the third solution I had: 
"Extend vtkPolyData to add the concept of visibility". I took 
vtkStructuredGrid as an example, noted where this->CellVisibility 
appears and extended vtkPolyData with the important methods: Initialize, 
GetCellType and GetCell_1-2, added Blank, UnBlank, etc.

Of course, it didn't work and I'm not sure why.  It seems GetCell and 
GetCellType are never called. I was sure that one method somewhere 
during the rendering process called them but it's not the case. What I 
don't understand then is, if all methods related to CellVisibility are 
not called, how can it works for vtkStructuredGrid? There's no example 
using vtkStructuredVisibilityConstraint. Do I need to pass the result of 
polydata->GetCellVisibilityArray() to another method?

Le 2014-05-21 10:43, Nil Goyette a écrit :
> Hi,
>
> I'm searching how to recreate the FiberNavigator [1] using vtk and I'm 
> stuck on one problem. As you can see in my screenshot [2], we use a 
> little teal cube to filter which fibers we want to see. The cube will 
> be a vtkBoxWidget and the fibers are a vtkPolyData. The problem is 
> that there's no concept of cell visibility in a vtkPolyData. I found 
> this feature in vtkStructuredGrid but I believe my data doesn't fit 
> the class' description. I found three ways to do what I want:
>
>  1. Use vtkExtractSelectedPolyDataIds to extract only the cells I
>     need. I think this would be super slow.
>  2. Add/delete cells when the cube pass by. I think this would also be
>     slow.
>  3. Extend vtkPolyData to add the concept of visibility
>     (vtkStructuredVisibilityConstraint). This looks like the best
>     option to me but I may be wrong.
>
> I wonder what's the best way to filter the fibers. Do you have any 
> suggestions for me? Thanks for your time.
>
> [1] https://github.com/scilus/fibernavigator
> [2] http://imgur.com/1edZpWT 
-- 
Logo Imeka <http://imeka.ca/> 	Nil Goyette, M.Sc.
Programmeur
www.imeka.ca <http://imeka.ca/>
819.820.5231

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.vtk.org/pipermail/vtkusers/attachments/20140523/2ba9df4c/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Imeka.png
Type: image/png
Size: 6630 bytes
Desc: not available
URL: <http://www.vtk.org/pipermail/vtkusers/attachments/20140523/2ba9df4c/attachment.png>