| | One of the most significant aspects of BRepFeat functionality is the use of local operations as opposed to global ones. In a global operation, you would first construct a form of the type you wanted in your final feature, and then remove matter so that it could fit into your initial basis object. In a local operation, however, you specify the domain of the feature construction with aspects of the shape on which the feature is being created. These semantics are expressed in terms of a member shape of the basis shape from which - or up to which - matter will be added or removed. As a result, local operations make calculations simpler and faster than global operations. In BRepFeat, the semantics of local operations define features constructed from a contour or a part of the basis shape referred to as the tool. In a SplitShape object, wires or edges of a face in the basis shape to be used as a part of the feature are cut out and projected to a plane outside or inside the basis shape. By rebuilding the initial shape incorporating the edges and the faces of the tool, protrusion or depression features can be constructed. More...
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