Yeah that’s my point. All the normal engineering steps apply for sure. Just some of them are made more difficult due to a complex shape instead of a beam.

Yes. These designs are basically highly optimized, non-uniform load structures. You validate their load capability the same way you validate complex parts designed by humans: finite element analysis (FEA).

Edit: FEA is how you validate before your first prototype is made. You also CNC or 3D print a prototype and physically stress it just like any other part. Design validation is NOT just done on paper. It also is done on prototypes made using non-production equipment / tooling.

A big one is that designing with this process means at every step you are highly dependent on complex software modeling. Instead of using well known design rules to develop your design, you have to run a sophisticated algorithm that probably needs a hefty amount of compute power. Then you have to run FEA on literally every part, again needing lots of resources. That kind of software isn’t cheap and neither are the computer clusters.

Also, you have to put a lot of effort into defining your requirements very precisely and uncovering hidden requirements. For example, if you need a lot of strength in a part do you need that in both directions or only one? If you only need strength in one direction the best solution might be a steel cable, but I don’t know if there algorithms would consider that.

There’s also part integration. Things have to be designed for manufacturing and service (part tolerance stack up, order of operations, tool and hand clearances, etc.)

You also have to carefully consider your validation and what assumptions it makes about the parts that might no longer be true.

In the end, generative design is probably only worth the effort for specific parts or even portions of those parts, not the whole product.

Aerospace is completely different to building design.

In aerospace designs are custom out of necessity due to each part being highly mass optimized, interdependent on other parts and having different design goals and trade offs from project to project. Also, each part is highly validated and inspected as well as painstakingly assembled in (usually) very clean environments. The exact safety factor of the product is well known and controlled to a low ratio.

In building design, designs are using either commodity parts or commodity materials that are produced too much less exacting precision, often made on site exposed to the elements. So design knows the exact safety factor isn’t known and needs to be large to make up for this. There’s also always human lives at risk.

So building design rightfully has to be very conservative, regulated and has no impetus to change quickly. Aerospace design has to be less prescriptive and less safe just to make it to orbit. That doesn’t mean there’s not a ton of very good engineering involved in both fields, it just means more design freedom for aerospace.

I agree that downsides should be discussed along with benefits.

I disagree that we don’t know how they work. Part of the process of generating these designs is defining the interfaces to other parts, the loads and the pass/fail criteria. You literally have to define how it works to the algorithm to get the design in the first place.

If you get those things wrong, even classically designed parts can fail. Garbage in yields garbage out.

This is also the reason for validation. Validation often finds unanticipated or misunderstood interactions and manufacturing defects. Which is why it’s needed regardless of design method.

And if a part fails, then you know something in the process (design or manufacturing) is flawed and you chase down the root cause, find an effective solution and correct the process that produced the issue.

Basically, it’s all standard engineering practices for bespoke designs. It’s not easy, but it’s nothing new.