This approach attacks the problem by modeling a 3D object by a set of 2D views. Think of the 3D object surrounded by a viewing sphere and pictures are taken from different points of the viewing sphere. Each picture is called an aspect .
Aspects are the same if the set of visible and hidden surfaces seen in both pictures are the same.
Equivalence relationship between views in graphs is isomorphic while visual events correspond to curves on the viewing sphere. This occurs when a vertex transitions between occlusion and disocclusion in the picture. You can construct an aspect graph by making each aspect a node in the graph and connect neighboring aspects with edges. 1.4 Problems with multiple views approach While the multiple views approach is sound in theory, this idea does not work well in practice due to too many aspects that are needed. Another problem with this method occurs because of bad segmentation.