Detail design, or design-for-manufacture, is the stage where the necessary engineering is done for every component of the product. During this phase, each part is identified. Tolerances, materials, and finishes are defined, and the design is documented with drawings or computer files. Increasingly, manufacturers and developers are turning to 3D solid modeling programs. Three-dimensional computer models form the core of today's rapid prototyping and rapid manufacturing technologies. Once the database has been developed, prototype components can be rapidly built on computerized machines such as CNC mills, fused deposition modeling (FDM) devices, or stereo lithography systems (SLA). This detail drawing courtesy of 4tek