Feature

The main design unit in the modern CAD, an element that sets the product form. Changing feature parameters can change the form of a designed product. Building 3D solid bodies most often requires such features as pad, shaft, rib, pocket, groove and slot (using the British engineering terms). The second group is based on modification of already built topological features of a 3D model -– fillet, chamfer, draft, etc. The third group includes the features built on the basis of curvilinear surfaces – split, thick, close. Finally, there is a group of features built on the basis of transformation of other features (displacement, rotation, reflection).

The variational approach to parametric design links parameters of these features with each other in a random manner, while knowledgeware engineering environment enables linking feature parameters with formula and rules, provided there are no circular references between parameters. Features are also used to design 2D profiles, 3D wire-frames, surfaces, sheet-metal work, assemblies and processes.