One embodiment of a modular base assembly comprises a frame and leveler assemblies used to support a vehicle model. The frame has a frame segment with several parts including a cross-support and a side-support having a surface defining a plurality of holes where model-making components can be attached and unattached thereto. Leveler assemblies level the base assembly, and each can include a wheel hub locator that adjustably fixes a hub along a longitudinal horizontal, a vertical, and a horizontal direction. Another embodiment comprises a motorized vehicle undercarriage that carries a frame. The frame has a platform with a top surface defining a plurality of holes in the form of a matrix. Model-making components can be attached and unattached thereto.

Auto-leveling is accomplished with linear actuators. Each actuator features 0-10” of movement up/down and an individual load capacity of 1½ tons, for a combined load of 12,000 lbs., a 24 volt motor, 110/230 AC power (no switch) and is PLC controlled for height. Leveling feedback is via high gain electronic inclinometer. Auto-leveling is achieved by moving the armature to the approximate height and pushing the single push button on the hand box to initiate the leveling sequence this is accomplished in less than two minutes. Tests have provided 0.010” levelness repeatedly. Actuators may be packaged inside or outside the frame.