Abstract: A method for the spatial mapping of a model of a surgical tool onto a spatial position of the surgical tool includes a) providing a surgical tool having a working part and a marker in the form of a visual image on a surface; b) providing a tool model of the surgical tool; c) providing a viewing device configured to be carried by a user and including a camera configured to capture a view and to generate camera data representative of the view; d) creating a spatial model of a space viewed by the camera; e) bringing the surgical tool within the space viewed b y the camera; f) identifying a representation of the marker in the camera data; g) determining a position and rotation of the representation of the marker with respect to the spatial model, and h) creating a spatial mapping of the tool model in the spatial model.