Selection in ParaView

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Selection in ParaView

• Utkarsh Ayachit
• Kitware Inc.

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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

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Focus on subset
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Track subset over time
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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.

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Selection Components

• Selection Inspector
• Inspect the active selection
• Spreadsheet View
• Inspect the selected data

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Active Selection 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

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

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What is shown in the view
Show only selected items
Attribute shown
Select block to inspect
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Selecting using 3D View

• Surface cells/points
• Cells/Points within a frustum
• Blocks in a composite dataset

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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

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Select Points on surface

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

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Selection Linking

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

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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

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Select Blocks

• Select blocks in a composite dataset

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Composite Datasets

• Composite datasets are datasets comprising of
  other datasets.
• Group together assemblies vtkMultiBlockDataSet
• Adaptive mesh refinement vtkHierarchicalBoxDataSe
  t

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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

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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

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Selecting using Selection Inspector

• Create new selections
• Convert selections
• id based to global id based
• frustum to id based
• Modify existing selection

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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

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Threshold based selection

• Select cells or points that have an attribute
  value within the specified range
• Created using Selection Inspector

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Labeling Selected Items

• Label selected cells/points using Selection
  Inspector
• Choose the array/id to label with

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Extract Selection

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

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Extract Selection

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

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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

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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

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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