Click Viewpoint tab Save, Load & Playback panel Saved Viewpoints drop-down, and choose the viewpoint that you want to review.
Click Review tab Redline panel Draw drop-down, and click Line String.
Click in the viewpoint to begin. Each time you click, a new point is added to the line string. When the string is complete, click the right mouse button to end the line, and you can then start a new line string.