Parametric blends for shape modeling

Blends are surfaces that arise in manufacturing and do not usually appear on blue-prints. Methods are presented for modelling them in CAD/CAM systems. Modelling of two types of blends for parametric surfaces is considered; rolling sphere blends and general cross-section blends. The blend surface design task is split into two subtasks: identification of the normal cross section as well as the path followed by it. The path is identified as the intersection of the offsets of the given two surfaces. The offsetting technique establishes a natural parametric correspondence between the two blend boundary curves. The design of the shape of the cross section curve is left to the user. This provides the flexibility demanded by the application at hand