Which term describes a product development process obtained through 3D, parametric and associative CAD systems?

• A. Top-down modelling
• B. Prototypes
• C. Scale drawings
• D. Sketches

Answer: (A)

Top-down modelling describes a product development approach where the overall geometry and design intent guide the creation of components. In 3D, parametric, and associative CAD systems, you build a master model with relationships and constraints so that dimensions and features propagate through the entire design. This means changing a key dimension or feature at the top level automatically updates all dependent parts and assemblies, keeping everything consistent and accelerating exploration of design variations.

This fits the description because it emphasizes interconnected, parameter-driven geometry rather than isolated parts, 2D drawings, rough sketches, or physical prototypes. Prototypes are physical iterations, scale drawings are 2D representations, and sketches capture early ideas without a linked, feature-driven model.