SOLIDWORKS Masterclass Assemblies focuses on building clean, efficient assemblies using structured design and effective mate control. It highlights using sub‑assemblies to reduce top‑level mates, aligning the first component to the assembly origin, and applying quick and reliable mating tools such as width mates, profile centre mates, smart mates and reference mates. The session demonstrates speeding up workflows using drag‑and‑drop placement, copy‑with‑mates, pattern‑driven components and mirror components. It also covers interference checks, collision detection, dynamic clearance, physical dynamics and mechanical mates like gears, belts and screws. The mate controller is used to create controlled motion, animations and configuration states.