[vtk-developers] Fwd: Surface

[Bill Lorensen]

This is definitely not a bug.

You should also apply:
BoundaryVertexDeletionOff()

It is on by default. The default behaviour will delete vertices on the
boundary. When you do the Append, the boundary vertices from adjacent
pieces will not match.

This does mean that you will have possibly many triangles at the
"seams". If this is troublesome trying making a second pass with
DecimatePro.

After trying this, if you still have problems, then it may be a bug of
a different kind.

Bill

On Mon, Feb 21, 2011 at 11:40 AM, Mark Roden <mmroden at gmail.com> wrote:
> Hi VTK developers,
>
> There appears to be some problems running decimation routines of large
> volumes in parallel.  This is a bug report forwarded by one of the
> gdcm contributors for their large project involving both gdcm and vtk.
>
> Thanks,
> Mark
>
>
> ---------- Forwarded message ----------
> From: totonixsame at gmail.com <totonixsame at gmail.com>
> Date: 21 February 2011 10:21
> Subject: Superficie
> To: Paulo Henrique Junqueira Amorim <paulojamorim at gmail.com>
>
>
> Hi,
>
> In InVesalius we generate a vtkPolydata from a medical vtkImageData
> using marching cubes. But the vtkImagedata we are working are very
> large, like 512x512x1000, in a 32-bit OS it crashes and is a lot slow.
> So we thought in parallelize this part of software, then InVesalius
> could generate vtkPolydata faster. To do that firstly we split the
> vtkImagedata in smaller pieces, to each pieces we do this pipeline:
>
> vtkMarchingCubes -> vtkTriangleFilter -> vtkDecimatePro
> (PreserveTopologyOn and SetTargetReduction(0.3)
>
> Each piece can run in parallel.
>
> After all piece are processed we join them, using this pipeline:
>
> vtkAppendPolyData -> vtkCleanPolyData -> vtkStripper
>
> Then it shows to the user. But it has a problems: In junctions there
> is some marks like showed in [1] and [2]. When I open the STL
> generated from that vtkPolydata in Meshlab, for example, in those
> junctions there are some holes [3] and [4].
>
> Do you have some idea why that problem occurs? I have to use some
> other filter(s)?
>
> Thanks!
>
> [1] - http://i.imgur.com/MLXPw.png
> [2] - http://i.imgur.com/DRFHy.png
> [3] - http://i.imgur.com/0RB45.png
> [4] - http://i.imgur.com/70fIa.png
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