This complex appearing model of a clutch assembly is actually very easy to create in CAD. The process involves creating 3D entities, and then adding and subtracting component parts until you arrive with exactly what you have envisioned. The clutch plate itself is a cylinder with many cylinders spaced around it, and then subtracted from it to produce the friction holes. The bolts are created with a 3D prism tool. What appears difficult is really simple, once you know the tools to use