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I am trying to display polygons in ParaView and VTK, but I do not
get correct "surface" view. It seems that it draws redundant lines
(areas); all excessive lines originated from point with index 0 and
each line end up to all other points. Then surface view fills the
area between consecutive redundant lines, sometimes with different
color. The issue can be accentuated by using a concave polygon.
Consider the following vtk file (file attached, <font face="Courier
New, Courier, monospace">Polygon.vtk</font>):<br>
<br>
<font face="Courier New, Courier, monospace"># vtk DataFile Version
3.0<br>
output of my filter<br>
ASCII<br>
DATASET POLYDATA<br>
POINTS 12 float<br>
-3 3 0<br>
-3 -3 0<br>
-2 0 0<br>
-1 1 0<br>
-1 -1 0<br>
0 2 0<br>
0 -2 0<br>
1 1 0<br>
1 -1 0<br>
2 0 0<br>
3 3 0<br>
3 -3 0<br>
<br>
POLYGONS 2 14<br>
8 0 2 1 6 11 9 10 5<br>
4 3 4 8 7</font><br>
<br>
Three points with indices 0, 5 and 10 are on a concave boundary
segment, with edges 0 to 5 and 5 to 10. However, surface view shows
a link from point 0 to 10 (screenshot attached, <font face="Courier
New, Courier, monospace">Polygon.png</font>). Same issue happens
from point 0 to point 1. If you try polygons with more vertices, you
can see it draws lines from point 0 to "all" other points. Only
wireframe view reveals the two polygons properly in this file.<br>
<br>
Additionally, I have attached an editted Polygon.cxx code from wiki
(files attached, <font face="Courier New, Courier, monospace">Polygon.cxx</font>
and <font face="Courier New, Courier, monospace">CMakeLists.txt</font>)
to display a simpler concave polygon with 6 vertices in VTK. Please
switch comments in actor properties to see the inconsistency between
surface and wireframe views.<br>
<br>
I would like to ask that is it a bug or am I doing something wrong?<br>
<br>
Thank you.<br>
<br>
-Siavash<br>
<br>
<pre wrap="">---------------------------------------------------
Siavash Ameli
Ph.D student at Mechanical and Aerospace Eng. Dept.
Illinois Institute Of Technology
10 West 32nd St. E-1, Suite 130H
Chicago IL 60616
Phone: (312) 567-3555</pre>
<br>
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