I wanted to wade into this a bit and offer some insight for anyone curious...
Generative Design from the Autodesk perspective is built upon four distinct pillars (as I call them). Those pillars are:
- Topology Optimization
- Lattice Optimization
- Trabecular Structures
- Topology Synthesis
It's worth talking about these in slightly more detail.
Topology Optimization
Topology Optimization is a branch of FEA studies where a given design space is run through a static stress solver to determine where the loads travel through the part as to remove non-critical mass/volume. The hallmark of this type of study is that the design space must be defined before the study can determine the shape. What this means is that topology optimization needs an existing shape to remove mass from. Because the initial conditions contain a fixed shape, there is typically only one optimization for a given set of inputs (meaning similar results would come from any package that does this type analysis). This is Inventor's Shape Generator and Fusion 360's Topology Optimization.

Lattice + Skin Optimization
Lattice and Skin Optimization is a branch of FEA studies where a given volume is replaced with an intentional lattice structure (or lattice and skin) to further save on weight and to intentionally route loads. This area of design is pretty bleeding edge and has yet to be fully validated in the context of engineering at large. While simulations and lab tests are validating this method of design, the long-term results are still out because of unknowns like fatigue and the progressive failure nature of a lattice. It should also be said that lattices can be used for reasons other than mass reduction. A common usage of lattices is to provide fluid flow through a normally solid boundary (e.g. airflow through a unibody drone design). Additionally, conformal lattices can be used as external scaffolds or as non-stochastic increases in surface area. In the Autodesk family, this space is currently represented by Netfabb Premium and Ultimate.

Trabecular Structures
Trabecular Structures are a stochastic approach to increase the surface area of a design. This also creates high surface roughness. The name comes from Latin for "small beams." The typical application here is the medical field where an implant is to interface with bone. The micro-pockets and high roughness are used to create a "biological velcro" where the bone grows inside to create positive locking between the implant and the host. Other uses of trabecular structures include embedding of chemicals inside the pores to provide a timed-release (e.g. targeted chemo or radiation therapy), high surface roughness for fluid flow (thermal or boundary layer), or the development of formed abrasive tools (e.g. surgical burrs). In the Autodesk family, this space is occupied by Within Medical. You could theoretically do the same with Netfabb and a very high number of lattice elements (though that would be a very heavy file).

Topology Synthesis
Topology Synthesis is a new an exciting offshoot from topology optimization where the initial shape is no longer a prerequisite. By leveraging cloud solvers and a myriad of input variables the system is able to generate unlimited results with different shapes. In this context, we switch from documenting the design we have in our brains with tools like Inventor and Fusion and instead move to letting the computer perform the actual design. This is interesting because it lets humans do what we do best - infer and distill contextual information - while letting the computer do what it does best - computation and alternative exploration. In the Autodesk family, this started out as a research project called Dreamcatcher. It was announced at AU2016 that Dreamcatcher would be undergoing commercialization efforts. Over the past year, the project has spawned Autodesk Generative Design (AGD). AGD is still in development; however, you can find information about it on the official blog, AU's online learning from last year (I spoke on it), or by just researching Dreamcatcher. If you search the forums for AGD you'll find a couple of minor references (largely by me). I'm not certain as to the status of the tech preview program at this juncture. It was announced at AU2017 that Fusion Ultimate subscribers would be able to access it, but I am not certain the availability at the moment.

(note: The only difference between each study shown here was a suggested seed. The loads, constraints, materials, targets, and parameters were identical.)
Hopefully, this sheds some light on the subject for those interested. Feel free to reach out via PM if you'd like a deeper discussion on how Generative Design is impacting manufacturing right now. It's not as science-fictiony as it seems...
K. Cornett
Generative Design Consultant / Trainer