This paper presents problems encountered within the simulation modeling community of General Motors when they are faced with the requirement to verify all new plant designs for their entire global manufacturing enterprise. Given that the Body Shop, Paint Shop, and General Assembly areas of an automotive plant are modeled independently in two different simulation packages, we desire this clinic session to address issues encountered when attempting to model the entire plant with one simulation package. Obtaining accurate total plant throughput from this one model representation is of interest. The Paint Shop, in particular, is modeled in a 3D simulation package and its results need to be represented correctly in terms that are interoperable with a 2D simulation package.