1. A computer-implemented method for creating a reference to data used to construct a computer-aided design model, the method comprising: from a subject computer-aided design model comprising model data, storing the model data with tracking data, wherein the tracking data identifies the model data; creating a reference, wherein the tracking data is associated with the reference to enable the reference to refer to the stored model data; and executing a modeling operation on the subject computer-aided design model, wherein the modeling operation is one of a geometry-based operation and a layout operation, and wherein executing comprises: retrieving the tracking data associated with the reference; traversing an assembly structure defining the computer-aided design model, the assembly structure configured to avoid loading all current model data each time a modeling operation is executed by loading portions of model data as a function of the modeling operation being executed and enabling a least amount of model data to be loaded for a greatest number of operations performed on the subject computer-aided design model, said traversing including attempting to match the retrieved tracking data associated with the reference to the tracking data stored with the model data; finding the tracking data stored with the model data; and returning geometric data stored in the model data.