Patent ID: 6978230

Claim:
A computer implemented method for annotating the surface of a computer model having a set of computer model vertices and computer model polygons, wherein the annotations comprise line segments and are specified as geometry in the form of a set of annotation vertices and annotation edges that connect the vertices, comprising the steps of: a) Selecting an annotation edge that connects a pair of the annotation vertices; b) projecting the pair of annotation vertices of the edge onto the surface of the computer model to obtain projected vertices; c) selecting a cutting plane between the pair of the projected vertices in which the cutting plane is selected by one of i) the pair of projected vertices and a midpoint of the relevant annotation edge and ii) the pair of projected vertices and an average of normals to surface polygons that contain the pair of projected vertices; d) cutting the surface of the model with the cutting plane, the plane intersecting the model on a cutting line; e) reconnecting the pair of projected vertices on the surface of the model by identifying points of intersection of the cutting plane with edges of the surface polygons, connecting one of the projected vertices to the nearest intersection point on the surface polygon edges, connecting the intersection points on each successive polygon that was intersected till the surface polygon on which the second projected vertex lies and then connecting a last intersection point to the second projected vertex, to produce the projection of the annotation edge on the computer model; and e) repeating steps b) to e) for each annotation edge in the annotation specified.