This study is interested in the attribution of technological properties to geometrical elements in a 3D architectural modeler. We propose an original method based on the principle of semantic groupings of faces by geometrical requests. We describe the method and the results of interviews led with architects to identify the relevant groupings, then we list the simple geometrical requests developed within the modeler for the selection of these groupings and we report the efficiency of the method on a case. We conclude by the benefits and limits of our method.