Hi, this video with some animation is an original way of showing a typical general Product Design Process cycle. The left part, CAD & CAE, indexes and rotates like a knob, to show various Iterations of Design, and the corresponding Revision numbers for Prototypes. These are typical of engineering changes that seem to be never ending !! . The loop between CAD-to-CAEFEA -to-prototyping-to- Validation testing - back to design changes, is shown as a rotating circle. That's life. The best designers and engineers will of course use their vast experience to manage a program with least number of changes and loops in design cycle, saving time and saving huge costs for the company in the process, and enabling faster Launches without problems. The stages leading to release for Final Tooling, followed by Final Testing, and no surprises should ideally be discovered at this stage, are shown to explain an ideal product development cycle. Real life could be more complicated than this.  br Visit kad24.com. Get in touch with kad24, for any advise or consultancy needs.