Custom weldment tube profiles are created by sketching concentric circles representing outer diameter and wall thickness, then configuring these dimensions into multiple size variations. Profiles are saved as library feature parts for use in weldments. Structural members are added to form the chassis, following rules for grouping parallel or connected segments. Additional groups are created for inclined or non‑parallel tubes, with trim and extend tools used to cleanly join members and define weld gaps. Bracing elements, roll hoops and bulkhead structures are built systematically, ensuring manufacturability and structural logic. Materials are applied to the completed frame so mass properties, centre of mass and mechanical characteristics can be evaluated for later simulation stages.