Abstract: A storage medium and computer system that, in an embodiment, in response to a request to create a target object, create a reference object for the target object and bind the reference object to a name space without the target object being instantiated. In response to an invocation of a method on the reference object, a determination is made whether a target object associated with the reference object exists. If the target object does not already exist, the target object is instantiated. If the target object does already exist, the target object is returned. In this way, target objects are not instantiated until a method on the reference object is invoked, which in an embodiment increases the performance of the invoking application.

Abstract: A storage medium and computer system that, in an embodiment, in response to a request to create a target object, create a reference object for the target object and bind the reference object to a name space without the target object being instantiated. In response to an invocation of a method on the reference object, a determination is made whether a target object associated with the reference object exists. If the target object does not already exist, the target object is instantiated. If the target object does already exist, the target object is returned. In this way, target objects are not instantiated until a method on the reference object is invoked, which in an embodiment increases the performance of the invoking application.

Abstract: A method, apparatus, system, and signal-bearing medium that, in an embodiment, in response to a request to create a target object, create a reference object for the target object and bind the reference object to a name space without the target object being instantiated. In response to an invocation of a method on the reference object, a determination is made whether a target object associated with the reference object exists. If the target object does not already exist, the target object is instantiated. If the target object does already exist, the target object is returned. In this way, target objects are not instantiated until a method on the reference object is invoked, which in an embodiment increases the performance of the invoking application.

Abstract: A computer-aided design system includes a method and apparatus for defining various datums with respect to a three dimensional object shown on the CAD system. The datum is labeled on the computer screen. The computer screen includes a cursor and menus for selecting a datum and various tolerance types with respect to the datum or a face related to the datum. A tolerance type and numerical value is selected for the tolerance and is also displayed on the screen. A geometric element from the CAD model or object displayed is selected to which the tolerance applies to the selected element. Data relating to the tolerance data, the geometric element, and the datum are stored within the computer. Linkage relationships are used to relate the data stored.