Unlike other CAD systems, you may make as many parts in a single Part Studio as you want. This technique is called Multi-Part Modeling and it’s very powerful because, as we’ve seen, you can make parts that highly depend on one another.
Bottom-Up Design is when a product is designed by creating sketches, then features, then parts (often one per Part Studio), and then assemblies. In this approach, the geometry is created starting with the lower level entities (like 2D lines and circles) up the hierarchy to the highest level assembly (such as the final product being built).
Top-Down Design is when the shape of an overall product is sketched first, and then different regions of that sketch are used to create the lower level parts and their features. Top-Down is a more intuitive way to approach a design because typically we, as designers, envision the final product first, then as time goes on, we refine the concept into finer and finer detail.