| | A topological attribute can be seen as a hook into the topological structure. To this hook, data can be attached and references defined. It is used for keeping and access to topological objects and their evolution. All topological objects are stored in the one user-protected TNaming_UsedShapes attribute at the root label of the data framework. This attribute contains map with all topological shapes, used in this document. To all other labels TNaming_NamedShape attribute can be added. This attribute contains references (hooks) to shapes from the TNaming_UsedShapes attribute and evolution of these shapes. TNaming_NamedShape attribute contains a set of pairs of hooks: old shape and new shape (see the figure below). It allows not only get the topological shapes by the labels, but also trace evolution of the shapes and correctly resolve dependent shapes by the changed one. If shape is just-created, then the old shape for accorded named shape is an empty shape. If a shape is deleted, then the new shape in this named shape is empty. Different algorithms may dispose sub-shapes of the result shape at the individual label depending on necessity: More...
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