In which entities can work points be defined or projected onto?

The correct choice highlights the various geometric features within engineering design where work points can be established or projected. Work points are critical in 3D modeling and drafting, as they act as reference points for creating relationships between different elements of a design.

Part faces, linear edges, arcs, and circles are specific features of 3D models where work points can be effectively defined. For instance, defining a work point on a part face can aid in positioning other components or features accurately in the assembly. Similarly, projecting work points onto edges and curves allows designers to ensure that parts fit together correctly, which is essential for the functionality of the final product.

In contrast, the other options encompass broader concepts or elements that are not specifically related to defining or projecting work points. While sketches and models are involved in design, they do not directly relate to the geometric features where work points are typically positioned. Understanding these definitions is essential for effectively utilizing computer-aided design (CAD) tools and ensuring precision in engineering tasks.