Boundary Representation (B-rep) is a method used in computer graphics and modeling to define the shape of 3D objects by specifying their boundaries - namely, surfaces, edges, and vertices. Instead of describing the interior of an object, B-rep focuses on the exterior features, allowing for detailed and accurate modeling. This approach is widely used in computer-aided design (CAD) and engineering because it enables complex shapes to be represented precisely, supports realistic rendering, and facilitates operations like editing and analysis of 3D models.