Abstract: A computer-implemented method of creating 2D annotation data for annotating one or more perception inputs comprises: receiving at the annotation computer system at least one captured frame comprising a set of 3D structure points, in which at least a portion of a structure component is captured; computing a reference position for the structure component within the frame; generating a 3D model for the structure component by selectively extracting 3D structure points of the frame based on the reference position; computing a projection of the 3D model into an image plane; and storing 2D annotation data of the computed projection in persistent computer storage for annotating the structure component within the image plane.