Computer 3D model is the basis for the yacht building. It's created in real dimensions, its developable surfaces and solids are basically parts almost completely ready for CNC cutting, waterjet and other computer- to- product machines, allowing much faster production process. This is the stage when free hand sketches and general arrangement / layouts are to be proven. Computer 3D modeling, as the final stage of engineering is the most appropriate way to confirm shapes and lines from previous phases, to improve looks, to help in ergonomics checks, to help in studies of all kinds of kinematic details, functional openings, etc.
Creation of a 3D model demands involvement of a naval architect. At this stage, he needs to create a perfect hull shape, to do measurements, to check materials he'd use, hydrodynamic characteristics, etc. All this makes this stage of design process almost crucial for the whole project.