For scatter_selection folder, there are three files as: points_selection_vispy.py(a standalone script), selection_common.py and selection_widget.py(these two are functionally diveded from points_selection_vispy.py).

For volume_selection folder, it's mostly the same as scatter points case, except using MultiVolume developed by @astrofrog on the repository.

Users can either run the standalone script with python points_selection_vispy.py or python volume_selection.py

or run the widget scripy with python selection_widget.py

There are four selection modes switched with key press:

• '1' stands for free lasso selection;
• '2' stands for rectangle shape selection;
• '3' stands for ellipse shape selection;
• '4' stands for picking (not available for volume selection yet)

While under selection mode, the mouse operation for controlling the viewport is not available, users could press one of above key press to swith between selection & view mode.