[vtk-developers] VTK 5.2

John Platt jcplatt at dsl.pipex.com
Tue Jun 17 15:06:37 EDT 2008



A couple of crashes I had in CVS version 14th Jan 2008.


If you try to render the prop assembly tree vtkActor > vtkPropAssembly >
vtkPropAssembly (from leaf to root), vtkProp3D::PokeMatrix() crashes
because this->CachedProp3D is NULL. The tree vtkActor > vtkPropAssembly
renders OK.

The same problem was reported some years ago


In vtkPropAssembly::BuildPaths(), the line




will always add a null matrix even if the prop is a vtkProp3D. I have
changed this to


    path->AddNode( prop, prop->GetMatrix() );


and my particular problem is resolved.



Clipping an unstructured grid containing (theoretically) more than 8
quadratic hex's with a plane may fail with an access violation copying
the cell data. In practice, at least 24 cells are needed on Win XP and
probably many more for nix.


I think the problem is in vtkQuadraticHexahedron::Clip() with the call 


            this->Hex->Clip( , , , , , , this->CellData, cellId, , );


this->CellData stores 8 identical copies of the quadratic hex's cell
data for each subdivided linear hex but cellId has a maximum value of
the number of cells in the grid - 1. The access violation occurs in
vtkTetra::Clip() in the calls outCD->CopyData() where an attempt is made
to copy cell data for cellId.


I think the call should be 


            this->Hex->Clip( , , , , , , this->CellData, i, , );


where 'i' is the index of the linear hex.




I don't understand why it is necessary to copy the cell data in the
first place. I would have thought that all subdivided cells have the
same cell data as the parent. In this case, dispense with this->CellData
and just use


            this->Hex->Clip( , , , , , , inCd, cellId, , );


A similar problem may also exist in vtkQuadraticHexahedron::Contour().


My apologies if you were not soliciting this type of response :-).








-----Original Message-----
From: vtk-developers-bounces at vtk.org
[mailto:vtk-developers-bounces at vtk.org] On Behalf Of David Cole
Sent: 17 June 2008 14:30
To: VTK Developers
Subject: [vtk-developers] VTK 5.2


Hello VTK developers,

Yesterday I merged in a handful of changes to the VTK-5-2 branch. Is
there anything else anybody knows about that should be merged to the
VTK-5-2 branch before we build a 5.2.0 release...? Any changes made to
CVS HEAD since April 28 when the branch was created that should be
merged over?

Let me know in the next couple of days if there is anything else.

David Cole
Kitware, Inc.

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