Generative design is a 3D modeling technology that is incorporated into the Fusion 360 CAD Software. Instead of modeling structural, load bearing designs, the user inputs the base geometry, the fixed geometry, and any and all forces that the part will undergo. After first running the simulation, the computer connects the base geometry with a solid piece of material than, by automatically running simulations, the computer cuts away unnecessary geometry which leaves us with a natural-looking geometry which efficiently connects load-bearing parts. For example, if I wanted to create a motor mount I would tell the computer to preserve the holes that mount the motor onto the part I am creating (lets call it 2 holes) and also the holes mounting my part to the chassis of the design (lets say there are 4 holes of this type). Because holes are empty, we need to give some thickness to the hole so we can create a ring around each of the 6 holes (2 motor holes, and 4 mounting holes). Before running the generative design process, we need to select our material and we also want to tell the computer that the 4 mounting holes are locked in place. We also can select the motor as an obstacle geometry so, when the computer is generating results, it will avoid intersecting into the motor. We then finally add in our forces (either in Newtons or in Pounds) and we run our simulation. After usually around 30 iterations the computer outputs a resulting design. We can scroll back in the design's timeline to see how it ended up with the result it did. If we don't like how the design turned out we can go back and change the input parameters. If we do like the design, we can then export the design into a new model and then we can actually edit the form (using Fusion 360's sculpting tool) and change certain geometry as we see fit. If we then want to make sure this final piece will be able to endure the forces we can run a simulation (also integrated in the Fusion 360 software) and confirm it is strong enough.
Generative design is great for 2 reasons. By nature of the process, it is efficient in every sense of the word: smallest design possible, uses minimal material, optimal strength and optimal weight. It is a great tool for 3D printing both functional mechanical pieces and aesthetic artistic sculptures. If you want a low cost, awesome looking, unique design then generative design is the right use-case. Some good examples uses of generative design is a shelf bracket, car frame, bike frame, and many more types of mounts, brackets and frames.
If generative design is extremely efficient, cool looking and modern then you might be asking why isn't it used everywhere? The answer comes down to manufacturing. Manufacturing these complicated, 3D structures is a very difficult process if you want to do more than 3D printing (and in some cases injection molding). There are ways to restrict the software so the part can be manufactured with a 3 axis and 5 axis CNC machine but it simply isn't as robust in those cases. This software excels when the constraints are on the forces, obstacle geometry and initial geometry and without any constraints in the generative process itself. It is very likely that, in the future, we will have robust generative design tools that can create machinable generative design parts, but Fusion 360's software is not yet there.