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IDProjectCategoryView StatusDate SubmittedLast Update
0011454ParaViewBugpublic2010-11-13 00:272010-11-16 18:19
ReporterJedrek 
Assigned ToKen Moreland 
PrioritynormalSeverityfeatureReproducibilityalways
StatusclosedResolutionnot fixable 
PlatformOSWindows OS VersionWindows 7 64 bit
Product Version3.8.1 
Target VersionFixed in Version 
Summary0011454: Paraview show nonsymmetrical visualizations for two rotated squares
DescriptionLet us consider two vtk files (file1.vtk, file2.vtk which are attached to this message). They show two theoretically the same squares (just rotated). Unfortunately the visualizations are not similar. Why these pictures are not symmetric? (compare file1.png, file2.png which are attached to this message).
I checked that in MayaVI with similar results.
I used VTK_QUAD, VTK_PIXEL, VTK_POLYGON with similar results. It looks like each square is created with two triangle. And these triangles are clearly visible.
I think that for square (the picture should be more symmetric).
Steps To Reproduceuse attached vtk files.
TagsNo tags attached.
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Attached Fileszip file icon file.ZIP [^] (8,358 bytes) 2010-11-13 00:27

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  Notes
(0023238)
Ken Moreland (manager)
2010-11-13 08:29

 The behavior you are seeing is an artifact of the rendering system of your system. Rendering hardware, and most software implementations, typically break polygons into triangles to streamline rasterization. The field you have defined on the square is highly nonlinear and therefore results in a different interpolation depending on which way the rendering system happens to divide the square into triangles.

I recently gave a more thorough description of the phenomenon on the ParaView mailing list: http://markmail.org/message/sbdhgr44rvzjcyqg [^]
(0023316)
Alan Scott (manager)
2010-11-16 18:19

 I also believe that Ken's explanation is correct. If you disagree, please either e-mail the ParaView e-mail list and start a discussion, or re open this bug explaining why you think that Ken is wrong.

 Issue History
Date Modified Username Field Change
2010-11-13 00:27 Jedrek New Issue
2010-11-13 00:27 Jedrek File Added: file.ZIP
2010-11-13 08:29 Ken Moreland Note Added: 0023238
2010-11-13 08:29 Ken Moreland Status backlog => @80@
2010-11-13 08:29 Ken Moreland Resolution open => not fixable
2010-11-13 08:29 Ken Moreland Assigned To => Ken Moreland
2010-11-16 18:19 Alan Scott Note Added: 0023316
2010-11-16 18:19 Alan Scott Status @80@ => closed

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