Line Above Selection
Function Description: This tool allows the user to select the point cloud according to the online method.
Steps
1.After clicking Line Above Selection 
button, the function is activated and selection mode will be on.
2.Left-click in the window to select the starting point, move the mouse, and preview the online area.
3.Finally, double-click the left button to end the selection, and identify the point clouds in the selected area for highlighting (red) display.
4.After the first selection is over, the next selection can be made on the basis of the first selection.
5.Each time the selection area is selected according to the reverse selection, the corresponding plus selection area or minus selection area will be selected.
Note: This function is only for point cloud data.