The present invention relates to a kind of method and system, come the first extension apparatus (14) for the first shape observed there is the first length and the elongated devices of the second sensing shape 1/10th seconds (16) to have the second length. First extension apparatus (14) and the second extension apparatus (16) are physically connected to the first and second length of upper at least part (28) each other. First sensing shape and the shape of the second sensing are to obtain from each other independently. The described method includes:: the first and second sensing shapes are provided as another first and second sensing shape of reference figuration as link shape； It determines the shape overlapped region along reference figuration and link, should be matched in the reference figure and the shape of link, since the first and second elongated devices of physical overlap (14,16) are in the region； It duplicates, overlapping region, the shape that the part of overlapping region reference figuration is connected to overlapping region, so that the shape of connection is envisioned as matching reference figuration in overlapping region.
