In AutoCAD 2D you learnt how to put your design ideas on electronic drafting board. The days are old where 2D drawings alone were used to design a structure or a component. The drawings created in 2D, though represented the engineering details, pre-requested by the manufacturer, it doesn't confine a solid view of your drawing. Although 2D drawings can produce gradient shades, yet they do not produce realistic effects. In these above cases, there is one thing that was missing – 3rd Dimension.
In today's fiercely competitive manufacturing market, "A 3D model is worth a 1000 2D drawings". A 3D model promotes greater degree of comprehension than an abstract line representation in 2D.