TABLE OF CONTENTS In engineering design modeling, base features created with simple standard geometries in Chapter Five are rarely capable of carrying out the desired functions alone because of limited modeling options or difficult approaches. To be useful, these base features need additional modeling element features and more practical approaches to accomplishing modeling actions. On one hand, from the viewpoint of engineering design modeling, additional element features are the constituents "built" into the base features. On the other hand, they are likely to be machined results on raw stock materials. A complete engineering design model is nothing other than a base feature with a series of additional modeling elements/ features. The presence of these features enables a design model to be a functional machine component.
Element features can be divided into two categories according to their functionality: functional and nonfunctional features.
Functional features are the modeling elements that enable the model to perform its desired functions, and they either play direct roles in installing individual components to form final machine assembly or are the structural element in the model. For example, in Figure 6-1 the function of the screw hole features is to install the bearing support to the base plate; and the rib on the bearing holder is to strengthen its load-carrying capability. Nonfunctional features are modeling elements that do not have a direct role in building the overall mechanical functions of the model but act by indirect means. For example, there are rounds (or blends)...
