A new method was presented for computing the tight-fitting enclosing minimum volume oriented bounding boxes for constructing the model of complex object point sets in three dimensions. The relationship between the convex hull and its minimum volume oriented bounding box with the smallest volume was analyzed，and four kinds of edge contact types were summarized. The optimal box orientations are uniquely determined by combinations of edges in the convex hull of the input point set. Empirical evidence shows that this process always yields the globally minimum bounding box by volume feature, which concludes that this method provides a good simulation.