Manufacturing products directly from CAD, for example rapid prototyping.
Direct manufacturing is an evolving concept in manufacturing technology. The idea is to obtain the advantages of conventional mass production (such as high output volume, low unit cost, reliable interchangeability and quality control, and minimized need for person-hours of labor) while bypassing its disadvantages (mainly the capital intensity and lead time associated with toolroom work). Another way to understand the concept is to view it as the next step in the gradual development of manufacturing technology, which since the Industrial Revolution has evolved from skilled handcrafts to armory practice to (what we currently call) conventional mass production. The next step involves further innovation in information technology (IT) and its further integration into manufacturing, to the point where computer-controlled machines can create finished products directly from information (via digital files, that is, "electronic blueprints") without the need for intermediate toolroom work. The analogy of a "next step" has its limits, as the evolution of IT-based automation in manufacturing technology has been a continuous spectrum rather than a set of discrete steps. However, the analogy is useful for basic understanding.
While armory practice and conventional mass production succeeded in drastically reducing the need for skill and human labor time per unit output of finished goods, they did not eliminate it. They did eliminate a good portion of it, and transferred another portion from the factory floor to the toolroom. (The latter transfer has often been called "building the skill into the machine tool.") Instant manufacturing aims to one-up this achievement by using IT to whittle down what remains of the need for human labor time (of any type—skilled or unskilled, factory floor or toolroom).
Some simple examples through which to understand this idea are the following:
If you have a robot that has the ability to move quickly while also knowing its position in 3D space to within a fraction of a millimeter, it is more efficient to have a computer program instruct the robot to move to a certain spot and drill a hole than to have a laborer measure carefully to the spot and drill, or to have a toolmaker create a jig or fixture for the laborer to use.
If you can create a plastic part by aiming lasers at certain spots where powder or liquid is changed to solid, then you don't need to make a mold, as would traditionally be needed for such parts.
Mechanical, electromechanical, and hydraulic forms of automation all existed in impressive states by the time of the second world war; but in order for instant manufacturing to evolve from pre-WWII-style mass production, computer technology was needed (transistors, integrated circuits, software, CNC, PLC, robotics, and so on). (Advancing materials science and engineering has also been key.) Although every decade since that war has brought impressive advances in the development of IT and its integration into manufacturing, an era of robust and widely distributed instant manufacturing is only now just beginning.