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| ID | Project | Category | View Status | Date Submitted | Last Update | ||||
| 0008080 | VTK | (No Category) | public | 2008-11-11 09:08 | 2016-08-12 09:55 | ||||
| Reporter | Thomas F Albrecht | ||||||||
| Assigned To | Kitware Robot | ||||||||
| Priority | normal | Severity | major | Reproducibility | always | ||||
| Status | closed | Resolution | moved | ||||||
| Platform | OS | OS Version | |||||||
| Product Version | |||||||||
| Target Version | Fixed in Version | ||||||||
| Summary | 0008080: FindCell in vtkPointData does not work for partitioned grids like those read with vtkXMLPUnstructuredGridReader | ||||||||
| Description | For grids that are made up of several parts, like those put together from parallel computations or read with one of the vtkXMLP* readers, the function FindCell() is not guaranteed to find the cell containing a point at the border of two parts of the grid. FindCell() uses the following strategy: Find the closest point to the query point and then check which one of the cells contains the query point. However, when the grid is made up of several parts, the same physical point may be listed several times in the mesh, once for each part of the mesh it is contained in. So the closest point used in FindCell is always has the correct coordinates but maybe the wrong ID. It could refer to the ID of the point with the correct coordinates but from a part of the grid that does not contain the query point. A solution, which I already tried out and which works is to try not only the closest points but the ClosestNPoints as returned by the point locator. Then, all point IDs referring to the closest physical point in the mesh can be tried out and the cell containing the query point can always be found. Another solution would be to establish cell neighborhood information when reading grids made up of several parts with vtkXMLPUnstructuredGridReader. | ||||||||
| Additional Information | I added a screenshot of the problem. We are trying to find the cell containing a query point (blue) in a grid read by vtkXMLPUnstructuredGridReader. The correct closest point is found. But only the first occurence of that physical point with a point ID of 314 is used. But the cells using this point (pink) do not contain the query point. The same physical point has been added by the vtkXMLPUnstructuredGridReader a second time and when using that point ID, the cell containing the point can be found. Note that here, several parts of the grid come together at this point, so the closest point is present several, not just two times of the grid. So when using FindClosestNPoints(), we have to look for as many points as there are possible occurrences of the same point in the grid. | ||||||||
| Tags | No tags attached. | ||||||||
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| Attached Files |  cellNotFound.png [^] (50,881 bytes) 2008-11-11 09:08
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(0026936) Thomas F Albrecht (reporter) 2011-07-01 08:58 |
Why has this expired? |
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(0037039) Kitware Robot (administrator) 2016-08-12 09:55 |
Resolving issue as `moved`. This issue tracker is no longer used. Further discussion of this issue may take place in the current VTK Issues page linked in the banner at the top of this page. |
| Notes |
| Issue History | |||
| Date Modified | Username | Field | Change |
| 2008-11-11 09:08 | Thomas F Albrecht | New Issue | |
| 2008-11-11 09:08 | Thomas F Albrecht | File Added: cellNotFound.png | |
| 2011-06-16 13:11 | Zack Galbreath | Category | => (No Category) |
| 2011-07-01 08:58 | Thomas F Albrecht | Note Added: 0026936 | |
| 2016-08-12 09:55 | Kitware Robot | Note Added: 0037039 | |
| 2016-08-12 09:55 | Kitware Robot | Status | expired => closed |
| 2016-08-12 09:55 | Kitware Robot | Resolution | open => moved |
| 2016-08-12 09:55 | Kitware Robot | Assigned To | => Kitware Robot |
| Issue History |
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