1. Selection in ParaView Utkarsh Ayachit Kitware Inc.

2. Selection • Mechanism to identify subset of a dataset • Focus on selected subset • Inspect properties of the subset • Further process subset alone • Track subset over time

3. Focus on subset

4. Track subset over time

5. Selection in ParaView • What are we selecting? • Data produced by a source • Active Selection • One application wide selection • All views show the same selection if possible • Creating a new selection results in removing the old one • Transient: cannot be saved in state files, does not respect undo/redo.

6. Selection Components • Selection Inspector • Inspect the active selection • Spreadsheet View • Inspect the selected data

7. ActiveSelection Inspector • Accessible through View | Selection Inspector • Used to create/modify active selection • Shows the properties of the active selection • Control how the active selection is shown

8. Create new selection Active selection properties Selection type Selected cells ids Selection display Properties/Labeling

9. Spreadsheet View • Used to view the raw cell/point data • To create: split an existing view and select “Spreadsheet view” • Display tab provides option to view only selected items

10. What is shown in the view Show only selected items Attribute shown Select block to inspect

11. Selecting using 3D View • Surface cells/points • Cells/Points within a frustum • Blocks in a composite dataset

12. Select Cells on surface • Used to select any set of visible cells on the surface of a dataset • Representation should be points / wireframe / surface / surface with edges • With 3D view active, use the ‘Select Cells On’ tool button (shortcut ‘S’) to enter selection mode • Click and drag to select cells

13. Select Points on surface • Same as selecting cells on surface except use ‘Select Points On’ tool button.

14. Selection Linking • Selection is linked among all views (whenever possible) • Active selection is shown in all view (whenever possible)

15. Select Cells Through • Select all cells intersecting a frustum • Use ‘Select Cells Through’ • Selection Inspector has a check button to show the selection frustum • Use ‘Select Points Through’ for selecting points

16. Select Blocks • Select blocks in a composite dataset

17. Composite Datasets • Composite datasets are datasets comprising of other datasets. • Group together assemblies: vtkMultiBlockDataSet • Adaptive mesh refinement: vtkHierarchicalBoxDataSet

18. Select Blocks • Use ‘Select Block’ (shortcut ‘B’) to select blocks in a composite dataset • Keep Ctrl pressed when clicking to add to existing selected blocks

19. Selecting using Spreadsheet View • Can create Point/Cell index based selections (depending on what attribute is being shown) • Click to select rows as one would in any spreadsheet application • Can use modifiers such as Ctrl, Shift while selecting • Selection is shown in all views

20. Selecting using Selection Inspector • Create new selections • Convert selections • id based to global id based • frustum to id based • Modify existing selection

21. Location based selection • Select cell enclosing the location or select point closet to the location within a threshold • Created using the Selection Inspector and changing the selection type to Locations • Provides widgets to specify locations

22. Threshold based selection • Select cells or points that have an attribute value within the specified range • Created using Selection Inspector

23. Labeling Selected Items • Label selected cells/points using Selection Inspector • Choose the array/id to label with

24. Extract Selection • Extract selected subset for further processing • Create ‘Extract Selection’ filter • Make selection and ‘Copy Active Selection’ • Hit ‘Apply’

25. Extract Selection • Once a selection is extracted it’s treated as a first class data source. • One can apply filters to it as usual. • Extracted selection get saved in state files.

26. Plot Selection over Time • Plot data variable changes over time for a set of cells or points • Use ‘Plot Selection Over Time’ filter • Make selection and ‘Copy Active Selection’ • Output can be shown on a XY plot

27. Plot Selection over Time • Changes for each cell/point selected can be plotted, one at a time, by choosing the block on the Display Tab

28. Conclusion • Selection provides mechanism to focus on a subset of the dataset • Selection identifies the cells/points in the output of a filter/source • Active selection is shown in all views (when applicable) • Selection inspector can be used to create/modify the active selection • Spreadsheet view can be used to explore the attribute values for the selected items • Extracting a selection makes it possible to further processes the selected subset