This tool turns on and off the walls whose surface normal is pointing away from your viewpoint.
Figure 10. Without backface visibility (left) and with (right).
This tool is useful when you wish to see through the near side of a building. With one camera on the outside both the inside and outside of a building can be easily viewed instantaneously in rview. For this tool to work, the surface normals of the wall surfaces must be oriented toward the inside of the building. What this tool in essence does is turn off the wall surfaces whose surface normal is pointing away from the viewpoint. For more information on orienting surface normals see Adjust Normal Orientation.
