Abstract: The approach includes three parts:(1) image information processing, (2) body primitives separating,(3) 3-D representation of engineering object. Part (1) symbolizes the image in figural form of loops of linesand curves suitable for higher level processing. Part (2) separates all body primitives which compose theobject in accordance with special expert rules in the field of engineering drawing and relations among itsthree views by heuristic inferring method. Part (3) represents the whole body on a two-level model net.This approach has been succesfully used by assembly robot in block world.