Abstract: An algorithm based on dynamic division of sub-views is proposed to find out profile loops of complicated three-views of complex solids with some elementary volumes concealed by the others.First,fundamental loops are searched using traditional turn-to-most-left method.Then,inertia loops are searched in unidirectional sub-views,which are divided from orthographic views using the fundamental loops as hints.Finally,bidirectional sub-views are divided using the double-matching-loops generated from the existing loops.The inertia loops are found out in the bidirectional sub-views.Using extrusion or rotation,the elementary volumes are generated from triple-matching-loops constructed from the loops found out previously,and Boolean operations are applied on the elementary volumes to generate the solution solid.Experiments show that the proposed algorithm can effectively and completely find out all profile loops of the elementary volumes of the complex solids,including the obscured ones,which ensures the correctness of the solution solid.