However, the calculation of the visible part of the object from the viewpoint involving thousands of objects is a time consuming task even for high-speed computers. Specifically, basic algorithms for point visibility, weak visibility, shortest paths, visibility graphs, link paths and visibility of all the questions discussed. It will also be useful as a reference for researchers working in algorithms, robotics, computer graphics and geometric graph theory, and some algorithms from the book can be used in a first course in computational geometry.