[vtk-developers] Why wasn't vtkCellArray in vtkPolyData designed similar to vtkCellLinks?

[Will Schroeder]

In the early days of VTK it was envisioned as a "read-only" system where
data was loaded and then viewed. The idea was to minimize data structure
size (as Dave says) yet enable more
sophisitcated topological representations on an incremental / as needed
basis.

With the success of VTK its usage pattern has changed. Many of us now want
to load and edit structures. Work has been done to create full-blown
topological hierarchies in VTK to support complex mesh editing operations
and engineering simulation (like adaptive refinement). While these have not
yet fully made their way into VTK proper, it is likely such structures will
be added to the system as funding and support becomes available.

W

On Fri, Feb 10, 2012 at 8:28 AM, David E DeMarle
<dave.demarle at kitware.com>wrote:

> Because iteration is the more common access pattern (most importantly
> when pushing the elements to GL). Thus making the primary structure a
> sequential layout and making the random access layout optional saves
> both time and memory.
>
> David E DeMarle
> Kitware, Inc.
> R&D Engineer
> 21 Corporate Drive
> Clifton Park, NY 12065-8662
> Phone: 518-881-4909
>
>
>
> On Thu, Feb 9, 2012 at 7:26 PM, Mingcheng Chen <linyufly at gmail.com> wrote:
> > Hi all,
> >
> > Currently, without vtkCellTypes we cannot randomly access cell in poly
> data
> > because there is no uniform "entry length" in vtkCellArray (cells may
> have
> > different number of connectivities).
> >
> > However, vtkCellLinks can support random access for every point, because
> it
> > uses local linked list in each entry.
> >
> > Why wasn't vtkCellArray designed like vtkCellLinks? If so, we can deal
> with
> > only three arrays instead of four.
> >
> > Could anyone please help me with that puzzle? What is the advantage of
> the
> > current design?
> >
> > Thanks!
> >
> > Best regards,
> > Mingcheng Chen
> > February 9th, 2012
> >
> > _______________________________________________
> > Powered by www.kitware.com
> >
> > Visit other Kitware open-source projects at
> > http://www.kitware.com/opensource/opensource.html
> >
> > Follow this link to subscribe/unsubscribe:
> > http://www.vtk.org/mailman/listinfo/vtk-developers
> >
> >
> _______________________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at
> http://www.kitware.com/opensource/opensource.html
>
> Follow this link to subscribe/unsubscribe:
> http://www.vtk.org/mailman/listinfo/vtk-developers
>
>


-- 
William J. Schroeder, PhD
Kitware, Inc.
28 Corporate Drive
Clifton Park, NY 12065
will.schroeder at kitware.com
http://www.kitware.com
(518) 881-4902
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/vtk-developers/attachments/20120210/c37c4c43/attachment.html>