A key difference between point clouds and mesh models is found in their digital representation and data structure. Point clouds are collections of individual points depicted in 3D space. Each point represents a specific location and can contain additional information like color or intensity. In contrast, mesh models are surfaced-based representations built from interconnected polygons like triangles or quadrilaterals. They provide a closed surface that approximates the shape of the object, with edges, faces, and vertices defining its structure. Point clouds retain the raw data and details, while mesh models offer a more compact and structured representation.