Solid modelling is a technique used in computer-aided design (CAD) and involves creating 3D digital models of objects that are solid in shape, rather than made up of surfaces or wireframes. It is a specialized skill that requires a high level of proficiency in CAD software and an understanding of engineering principles and design. It is widely used in engineering, manufacturing, product design, and architecture. Solid modeling allows designers to make precise measurements, simulate real-world conditions, and analyze the physical properties of objects before they are built or manufactured.