Selection in ParaView

Utkarsh Ayachit

Kitware Inc.

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

Focus on subset

Track subset over time

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.

Selection Components

• Selection Inspector• Inspect the active selection

• Spreadsheet View• Inspect the selected data

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

Create new selection

Active selectionproperties

Selected cells ids

Selection type

Selection displayProperties/Labeling

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

What is shown in the view

Show only selected items

Select block to inspect

Attribute shown

Selecting using 3D View

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

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

Select Points on surface

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

Selection Linking

• Selection is linked among all views (whenever possible)

• Active selection is shown in all view (whenever possible)

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

Select Blocks

• Select blocks in a composite dataset

Composite Datasets

• Composite datasets are datasets comprising of other datasets.

• Group together assemblies: vtkMultiBlockDataSet

• Adaptive mesh refinement: vtkHierarchicalBoxDataSet

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

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

Selecting using Selection Inspector

• Create new selections• Convert selections

• id based to global id based• frustum to id based

• Modify existing selection

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

Threshold based selection

• Select cells or points that have an attribute value within the specified range

• Created using Selection Inspector

Labeling Selected Items

• Label selected cells/points using Selection Inspector

• Choose the array/id to label with

Extract Selection

• Extract selected subset for further processing

• Create ‘Extract Selection’ filter• Make selection and ‘Copy

Active Selection’• Hit ‘Apply’

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.

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

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

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