disclosed is a method for converting a freehand drawing into a 3d model corresponding to the freehand drawing in real time . this method can be used to automatically convert a picture of an object into a 3d model of the object for further interaction . the method can seamlessly be implemented by optical head - mounted computers to convert the picture of the objects located in front of the user into 3d models , even showing parts of the objects that are hidden from the user &# 39 ; s direct line of view .