One master geometry everything else is built from: the model, mechanism positions, drawings and renders.
Take the geometry from a sketch, photos, a video or your STEP and fix the key dimensions
Build a parametric model and assembly with real bought-in parts from manufacturer STEP files
For mechanisms, define the positions and check interferences in each, as in the AP17 boom and the KD304 housing
Run repeat products through a Fusion 360 API script: change the data and the model and drawings rebuild themselves
Issue F3D, STEP, STL or DXF, drawings and renders from the same model