Its really a two step process with engine parts. You have to add machining allowances and taper to some surfaces. If you set it up correctly in 3D, you can toggle the machining allowances/taper on and off, since you need them on for printing 3D patterns, and off for creating 2D drawings.
I use Solidworks, not Fusion 360, but generally speaking, both will do the same functions. There is a list of components on the left side of the screen, and you can toggle things on and off using the light bulb? in Fusion. So I assume Fusion is like SW in that you can group components into names, and then toggle the names on and off. You can always toggle the machining tolerances on/off manually. I add the machining tolerances and draft at the end of a part creation, so that all of the toggled stuff is at the bottom of the list on the left. I will look for a part where I have that function set up. Edit: Generally, you have to turn off fillets, machining allowances, sometimes tapers, etc. else the 2D drawings may become unusable. The 2D drawings represent the parts in their final machined state; at least that is how I set them up. Edit02: One other thing that I do is use a different color for machining allowances, so that it is immediately apparent when they are turned on (a brilliant color). I basically offset the sketch slightly (the width of the desired machining allowance), and then loft that shape with draft angle. You have to first determine which surfaces need machining allowances, and then which surfaces need machining allowances and draft angle. Not every machining allowance has a draft angle. .
