Computing constant offsets of a NURBS B-Rep

Abstract

An approach for the automatic offset of a NURBS B-Rep has been presented which can be used for a class of manifold B-Reps. The approach offsets each of the trimmed surfaces (faces) of the B-Rep and then removes the gaps and intersections between offset faces automatically, if any. The offset B-Rep is then created by sewing all the updated offset faces. The practical approach and the treatment of the subject presented are unique and have not been reported earlier. The approach works under the assumption that the number of faces in both base and offset B-Reps is the same. It further assumes that the faces are at least G 1 continuous and non-self intersecting after constant offset. The present approach has given accurate and robust offsets of many lay-up surfaces (B-Reps) in the composite laminate modeling. The approach has better error control. Some of the offsets of lay-up surfaces that are generated using this approach have been presented.