The current article presents a new approach to computer aided design based on an abstract geometric entity called a C-loop (Convex/Concave-loop). The approach currently being developed overcomes design limitations in current systems. Design-by-features systems are fast, but not flexible. Design-by-surfaces systems are flexible but cumbersome to use. The current research integrates a design-by-features approach with a design-by-surfaces approach followed by feature recognition. It allows the designer to create a design using design features and to modify these features as needed. The C-loop is the design feature that allows such flexibility. Subsequent to the design step, features pertinent to manufacturing are recognized from the model to perform Design-for-Manufacturability evaluation of the part.