Abstract: A consultation system enables a user of a lightweight client terminal (3) to interact with a three-dimensional digital model by displaying images produced in a server (2) from a detailed version of the model and displaying, during manipulation of the observation conditions, images calculated in the client terminal (3) based on coarsened data received from the server (2) and representing a simplified version of the model's geometry. The detailed images are accompanied by semantic mappings specifying, for the image pixels, an identifier of the part represented at the corresponding image location. The user designates a part in the model by indicating an image pixel and the user terminal identifies the part by referring to the semantic mapping. Parts selected by the user are highlighted by displaying over the main image either an image produced from the semantic mapping or a thumbnail calculated from the digital model.