In this paper we present a method to determine which symbols are probable to be found in technical drawings using vectorial signatures. These signatures are formulated in terms of geometric and structural constraints between segments, as parallelisms, straight angles, etc. After representing vectorized line drawings with attributed graphs, our approach works with a multi-scale representation of these graphs, retrieving the features that are expressive enough to create the signature. Since the proposed method integrates a distortion model, it can be used either with scanned and then vectorized drawings or with hand-drawn sketches.