Sometimes caves are so complicated that looking at a line plot can be very confusing. Line plots are two dimensional, but caves are three-dimensional. This means that you cannot tell which passages are far away and which passages are near. In fact, passages that appear to be close together can actually be hundreds of feet apart.
Stereo Mode. To solve this problem, the Viewer allows you to create and view true three-dimensional images of a cave. The Viewer creates three-dimensional images using the method called "stereo pairs." With stereo pairs, you can view the cave in three dimensions and see exactly how the cave is constructed. You can enable the Stereo Viewing option by clicking-on the Stereo button on the tool bar or by selecting the "Display->Show->Stereo View" option from the menu bar.
Here is detailed information about stereo viewing: