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<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:navy'>Hello, I am studying the problem
of associating data to vtkPolyData</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:navy'>What happens if, for
example, you call vtkTriangleFilter on a vtkPolyData composed of several
polygons, each being assigned an ID in the vtkPolyData “main” field
data array?</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:navy'>Is it necessary to handle
the inheritance of those Ids to all the created triangles, which means handling
polygons one by one and recreating a vtkPolyData for input for each of them.</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:navy'>This issue occurs with
nearly all “complex” processing, and it is a big amount of work to associate
Ids with each new cells created (I am also thinking about banded contours, etc)</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:navy'>Sebastien</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal style='margin-left:35.4pt'><font size=2 face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma'>-----Message d'origine-----<br>
<b><span style='font-weight:bold'>De :</span></b> vtkusers-admin@vtk.org
[mailto:vtkusers-admin@vtk.org] <b><span style='font-weight:bold'>De la part de</span></b>
Malcolm Drummond<br>
<b><span style='font-weight:bold'>Envoyé :</span></b> mercredi 25 février
2004 15:33<br>
<b><span style='font-weight:bold'>À :</span></b> vtkusers<br>
<b><span style='font-weight:bold'>Objet :</span></b> Re: [vtkusers]
associating datra to polydata</span></font></p>
<p class=MsoNormal style='margin-left:35.4pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'> </span></font></p>
<div>
<p class=MsoNormal style='margin-left:35.4pt'><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial'>Hi Sebastien</span></font></p>
</div>
<div>
<p class=MsoNormal style='margin-left:35.4pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'> </span></font></p>
</div>
<div>
<p class=MsoNormal style='margin-left:35.4pt'><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial'>There is the issue of
'compound' objects: ie when you glyph data associated with
points or when you tesselate or otherwise decompose concave polygons
and/or polygons with internal boundaries into simpler primitives. In both
cases, to avoid a massive duplication of data, I append an array that
just stores indexes into the original cell-ids or data (which I usually
keep out of the pipeline). When a pick takes place, the cell-id is
used as an index into the stored indexes - and so on to the
original data.</span></font></p>
</div>
<div>
<p class=MsoNormal style='margin-left:35.4pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'> </span></font></p>
</div>
<div>
<p class=MsoNormal style='margin-left:35.4pt'><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial'>I visualize a lot of mining
layouts that use an arc/node model similar to many GIS. In my
reader I build the polygon boundaries (internal and external) and then
tessellate, after which I add the triangular cells to the polydata. I have
two arrays in the cell-data, one for the scalar value of interest and the
other for the original polygon id, which are also updated as the triangles are
added. I've also used this approach to visualize polygon
data from shapefiles and associated dBase tables.</span></font></p>
</div>
<div>
<p class=MsoNormal style='margin-left:35.4pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'> </span></font></p>
</div>
<div>
<p class=MsoNormal style='margin-left:35.4pt'><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial'>I've used a
similar technique glyphing seismic events from an access database.
I wrote my own glyph filter but I see there is an option in vtkGlyph3D to
store ids in the point data (which you could still get at using
vtkPolyData::GetCellPoints if you used a cell picker).</span></font></p>
</div>
<div>
<p class=MsoNormal style='margin-left:35.4pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'> </span></font></p>
</div>
<div>
<p class=MsoNormal style='margin-left:35.4pt'><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial'>I think the most efficient approach
is to only put data relevant to the visualization into the pipelines (plus one
array for indexes if required) - keep additional data upstream or out
of the pipeline and use indexing to get it when required.</span></font></p>
</div>
<div>
<p class=MsoNormal style='margin-left:35.4pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'> </span></font></p>
</div>
<div>
<p class=MsoNormal style='margin-left:35.4pt'><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial'>HTH</span></font></p>
</div>
<div>
<p class=MsoNormal style='margin-left:35.4pt'><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial'>Malcolm</span></font> </p>
</div>
<div>
<p class=MsoNormal style='margin-left:35.4pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'> </span></font></p>
</div>
<div>
<p class=MsoNormal style='margin-left:35.4pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>----- Original Message
----- </span></font></p>
</div>
<blockquote style='border:none;border-left:solid black 1.5pt;padding:0cm 0cm 0cm 4.0pt;
margin-left:3.75pt;margin-top:5.0pt;margin-right:0cm;margin-bottom:5.0pt'>
<div style='font-color:black'>
<p class=MsoNormal style='margin-left:35.4pt;background:#E4E4E4'><b><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial;font-weight:
bold'>From:</span></font></b><font size=2 face=Arial><span style='font-size:
10.0pt;font-family:Arial'> <a href="mailto:maraux@ondim.fr"
title="maraux@ondim.fr">Sébastien MARAUX</a> </span></font></p>
</div>
<div>
<p class=MsoNormal style='margin-left:35.4pt'><b><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial;font-weight:bold'>To:</span></font></b><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'> <a
href="mailto:vtkusers@vtk.org" title="vtkusers@vtk.org">vtkusers@vtk.org</a> </span></font></p>
</div>
<div>
<p class=MsoNormal style='margin-left:35.4pt'><b><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial;font-weight:bold'>Sent:</span></font></b><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'> Tuesday,
February 24, 2004 4:40 PM</span></font></p>
</div>
<div>
<p class=MsoNormal style='margin-left:35.4pt'><b><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial;font-weight:bold'>Subject:</span></font></b><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'> [vtkusers]
associating datra to polydata</span></font></p>
</div>
<div>
<p class=MsoNormal style='margin-left:35.4pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'> </span></font></p>
</div>
<p class=MsoNormal style='margin-left:35.4pt'><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial'>Hello,</span></font></p>
<p class=MsoNormal style='margin-left:35.4pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'> </span></font></p>
<p class=MsoNormal style='margin-left:35.4pt'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'>I am working in GIS
field, where many polygons/lines or points groups are associated with data
(data for points, for lines, for polygons, and for general group information).</span></font></p>
<p class=MsoNormal style='margin-left:35.4pt'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'>What is the simpliest way
of keeping my associated information (which can be float, double, string
arrays) when I convert a GIS format into a vtkPolyData + ???(for associated
information)</span></font></p>
<p class=MsoNormal style='margin-left:35.4pt'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'>And keep the link between
information and what it is relevant to (points with their data, lines with
their data, general group data) ?</span></font></p>
<p class=MsoNormal style='margin-left:35.4pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'> </span></font></p>
<p class=MsoNormal style='margin-left:35.4pt'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'>Seb</span></font></p>
<p class=MsoNormal style='margin-left:35.4pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'> </span></font></p>
<p class=MsoNormal style='margin-left:35.4pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'> </span></font></p>
<p class=MsoNormal style='margin-left:35.4pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'> </span></font></p>
<p class=MsoNormal style='margin-left:35.4pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'> </span></font></p>
</blockquote>
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