[vtkusers] problem creating a vtu file with a VTK polyhedron

[kenichiro yoshimi]

Hello,

OpenGL may not render non-convex polygons correctly, hence polyhedrons
with concave faces too.
http://vtk.1045678.n5.nabble.com/Polyhedron-with-concave-faces-td4363498.html

In my experience, multiple non-convex polyhedrons which are mounted
side by side are correctly displayed  even though the rendering fails
for an individual concave polygon. (Please see the attached)

By the way, the data of "connecitivity" and "offsets" in the vtu file
may be wrong.
---
<DataArray type="Int64" Name="connectivity" format="ascii"
RangeMin="0" RangeMax="9">
0 1 2 3 4 5 6 7 8 9
</DataArray>
<DataArray type="Int64" Name="offsets" format="ascii" RangeMin="10"
RangeMax="10">
10 </DataArray>
----

Thanks

2017-12-11 8:20 GMT+09:00  <JFSLB at gmx.de>:
> <VTKFile type="UnstructuredGrid" version="1.0" byte_order="LittleEndian" header_type="UInt64">
> <UnstructuredGrid>
> <Piece NumberOfPoints="10" NumberOfCells="1">
> <CellData Scalars="level">
> <DataArray type="Float32" Name="level" format="ascii" RangeMin="0" RangeMax="0">
> 0
> </DataArray>
> </CellData>
> <Points>
> <DataArray type="Float32" Name="Points" NumberOfComponents="3" format="ascii" RangeMin="-1" RangeMax="1">
> 0.0204729 -0.000857723 0.0396787
> 0.0206677 -0.000857723 0.038172
> 0.0212252 -0.000857723 0.038172
> 0.0212252 -0.000857723 0.0396787
> 0.0207424 0.0006489 0.038172
> 0.0207424 0.0006489 0.0387988
> 0.0206286 0.0006489 0.0396787
> 0.0212252 0.0006489 0.0396787
> 0.0212252 0.0006489 0.038172
> 0.0207501 -6.0656e-05 0.038172
> </DataArray>
> </Points>
> <Cells>
> <DataArray type="Int64" Name="connectivity" format="ascii" RangeMin="0" RangeMax="6">
> 0 1 2 3 4 5 6
> </DataArray>
> <DataArray type="Int64" Name="offsets" format="ascii" RangeMin="7" RangeMax="7">
> 7 </DataArray>
> <DataArray type="UInt8" Name="types" format="ascii" RangeMin="42" RangeMax="42">
> 42
> </DataArray>
> <DataArray type="Int64" Name="faces" format="ascii" RangeMin="0" RangeMax="9">
> 7
> 4 0 1 2 3
> 5 4 5 6 7 8
> 5 9 4 8 2 1
> 4 6 0 3 7
> 4 2 8 7 3
> 3 9 5 4
> 5 6 5 9 1 0
> </DataArray>
> <DataArray type="Int64" Name="faceoffsets" format="ascii" RangeMin="38" RangeMax="38">
> 38
> </DataArray>
> </Cells>
> </Piece>
> </UnstructuredGrid>
> </VTKFile>
>
>
> On 10.12.2017 22:56, Bill Lorensen wrote:
>> Post the new data set please.
>>
>> On Dec 10, 2017 4:08 PM, <JFSLB at gmx.de> wrote:
>>
>>     I have reversed the order in "faces" so that the normals of the polygons point outwards, but he image is still the same. I have also reversed the order in "connectivity" but that did not help. For some reason two polygons (one in the x-y-plane and one in the x-z-plane) are rendered as a polygons with 4 points although they contain 5 points.
>>
>>     When I generated the data set there were some duplicated vertices, i.e. vertices with identical coordinates but different index and only one of the polygons was rendered incorrectly. I eliminated the duplicates and the second polygon was rendered incorrectly. I have no idea if that helps.
>>
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