Click the Front Facing check box on the Pointcloud Operator dialog box if you only want to select the points that are front facing in the selection view. When you disable this check box, PC-DMIS selects the points that are in both the front and rear facing views.
To see the front and rear faces as contrasting colors, right-click the pointcloud in the Graphic Display window and select Pointcloud Display | Two sided.
The pointcloud must have stripe information or IJK values for each point to use this option.
Examples of Selection View (left), Selection with Front Facing disabled (middle), Selection with Front Facing enabled (right)