Part designing is the section where you can design specific components of the machine you are making. For example if you are making an engine, then the piston, connecting rod, screws, etc. are the individual parts that u have to design separately in part designing. Later you assemble them.
The Part Design application makes it possible to design precise 3D mechanical parts with an intuitive and flexible user interface, from sketching in an assembly context to iterative detailed design. Part Design application will enable you to accommodate design requirements for parts of various complexities, from simple to advance.
This application, which combines the power of feature-based design with the flexibility of a Boolean approach, offers a highly productive and intuitive design environment with multiple design methodologies, such as post-design and local 3D parameterization.
As a scalable product, Part Design can be used in cooperation with other current or future companion products such as Assembly Design and Generative Drafting.