I just noticed that Fusion 360 SIM also has generative design / shape optimization included for Mac and PC which is great by the way.
I am curious what the different between the Fusion internal and stand alone app is.
From screenshots I can see maybe some soft of comparison of results which were created via adjusting slider values?
Claas Kuhnen
Faculty Industrial Design – Wayne State Universit
Chair Interior Design – Wayne State University
Owner studioKuhnen – product : interface : design
Hey Claas,
Here's a good thread discussing the differences. Let me know if there's anything else you're curious about, I can find someone on that team to chime in-
Claas Kuhnen
Faculty Industrial Design – Wayne State Universit
Chair Interior Design – Wayne State University
Owner studioKuhnen – product : interface : design
No, but at least answers the question you asked me offline 😉
(difference between shape/topology optimization and generative design)
The thread thread was referred to was exactly what I was looking for but I could not find it in my link collection and the search fictionality of the forum is a unhappy mixture between rudimentary and useless.
Topology optimization has been part of Fusion for a while, but Generative design was added just recently and currently is only accessible for Fusion 360 Ultimate Users with Windows machines. I've head from the Program Manager, however, that they are working on making it available for macOS.
@MikeSmell_ADSK might be able to answer the A vs B question.
I'll elaborate on my answer in the other thread. This is also the exact topic of my AU course this year...
Both systems are topology optimization algorithms, but their approach is dramatically different.
The more traditional approach is referred to as SIMP (solid isotropic microstructure penalization) which uses an FEA engine to determine what voxels are required (and which voxels are not) in order to carry the load. Technically speaking, the SIMP method looks at the voxels as partial density between 0 and 1 (0 being empty space, 1 being fully dense). Since this is (nearly) impossible to realize in all practicality, the penalization occurs which forces the voxel to either go to a density of 0 or 1. This is where the "load path criticality" comes from - When you run a shape optimization inside of Fusion you tell the algorithm what percentage of mass you want to remove. The solver then shows you a result at that reduction with the LPC set to 0.5. You can then adjust the slider up and down to show where each of the voxels falls in that partial density scale for the given mass removal amount. In other words, if the LPC is set to ZERO then the voxels present have at least a ZERO density. As that slider moves up, the voxels start to remove because they begin to have a calculated density lower than the LPC threshold. It becomes up to the designer to identify what level of reduction you're comfortable with (with the understanding that the 0.5 LPC result should carry the loads imposed during the optimization). This solve method (as currently implemented) can only find a single solution for the given domain - whether it is a global minima or just a local is a total unknown.
The level set approach (Generative Design) uses a different math model to achieve similar types of results. The math here gets more than a little deep. Essentially, the solver uses iterations (time steps) to move the surface boundary of the part in question in a normal direction to the load path while satisfying the parameter for minimal strain. There is a bit of "philosophy" here as well, that given enough iterations, the solver would be able to find the global minima of a design domain. I say "philosophy" because it's really an academic exercise rather than a practical reality. It quickly comes down to the designer's intuition as to whether continuing on is really worth it.
The math models aren't all that's happening here, though.
In reality, both methods are topology optimization. What makes Generative Design so different is a couple of features that other products don't offer:
1) Generative Design works specifically with interface geometry. You include all your bosses and flanges and then the first step that happens behind the scenes is that the design space is shrinkwrapped - to give a starting shape of the general envelope of your part. From there on, the two systems are quite similar in terms of (end) results. You do have the ability to provide specific starting geometry (see #3).
2) Level set methods are highly scalable across multiple processors. This means that tools like GPUs can crunch the numbers faster than a CPU would. This further manifests itself as being a differentiator when you begin to throw in multiple variables (e.g. multiple materials, multiple fabrication types). When you see Generative Design pump out tons of different results, it is because the solvers are actively chewing on different variables. In theory, you could do the same thing with a SIMP tool - but you'd be running individual instances on individual CPUs.
3) The level set method can be "hacked" to improve performance and to "guide" the solver to a specific solution. One of the math quirks of the level set method is that the more surface area a shape has, the faster the algorithm can remove mass. When we couple this knowledge with the ability to include specific starting shapes, we can then intentionally seed high-surface area models into the solver to improve the mass burn down rate. A second math quirk is that the solver can easily create (or merge) holes, but it struggles with where to put them. We can leverage this by including starting shapes with a large number of topological holes to get entirely different results than you might expect. Lastly, we can include exotic seeds (specific shapes) to guide the solver into a quasi-aesthetic. You may reach an acceptable answer based on your specific input shape - but it may not be the global minima - and that may be your intention all along.
I like to show (3) as an example:
Here is a design space where I want to create a shelf bracket.
If I don't include any starting shape, I tend to get things that look something like this:
But maybe I want to follow a more specific look. So, I add this as a starting shape:
And here is a result with that as a seed:
You'll see my comments around the forums that this isn't the black box where design goes to die that most people think it is. No, I don't have explicit control over the outcome... but the purpose of these softwares (at this stage of the development of them) is primarily about ideation and not end-design creation.
I'm sure I've left off info (the level set method is difficult to explain without more time/graphics/math). Keep asking questions, though (as it also helps me prep for AU!).
@I_Forge_KC wrote:
... but the purpose of these softwares (at this stage of the development of them) is primarily about ideation and not end-design creation.
We are sorry to inform you that at this time unfortunately your application for the position of the Marketing Director has been rejected.
😄
Claas Kuhnen
Faculty Industrial Design – Wayne State Universit
Chair Interior Design – Wayne State University
Owner studioKuhnen – product : interface : design
oh nice - I guess those who applied then did not get a rejection email.
Claas Kuhnen
Faculty Industrial Design – Wayne State Universit
Chair Interior Design – Wayne State University
Owner studioKuhnen – product : interface : design
Thank you for the longer explanation. What I did not know is the desktop app uses a different math model.
From the images it looked like the end result is more or less the same just the way you got to there is different.
Somewhat ten years ago SolidThinking brought this type of structural design proposal tool to the Mac and PC and it is great that this is to a certain degree also now part of Fusion 360.
The shape optimization in Fusion will be more than sufficient for my students to learn and work with since they are not engineers but designers.
If I look at many of those examples online I cannot help but chuckle a little when I see the untouched shapes.
The GM example makes sense because it is a hidden part but for visible parts I somewhat want to clean up the surfaces.
I just by accident discovered the shape optimization in the SIM module since we hardly ever do sims, so this is great to know now that we can use it for a project.
Students will love it.
Claas Kuhnen
Faculty Industrial Design – Wayne State Universit
Chair Interior Design – Wayne State University
Owner studioKuhnen – product : interface : design
I have not toyed around with these abilities. I was under the impression that Topology/Shape optimization was already part of Fusion 360 and that Generative Design was added recently but is only currently available for Fusion 360 Ultimate and Windows users.
My assumption was that this is what is behind the new "G" icon in the Fusion 360 main tool bar.
So I am not sure what Claas is referring to as the Desktop app. What am I missing ?
Aha. Thanks for the explanation.
I knew that export for shape optimization was in mesh format only and had assumed it would be the same for generative design. Currently not very usable in Fusion 360 without some T-Spline skills but I'd guess for more intricate results that would get very tedious very fast.
@kenikd I see what you mean with generative design - in this case here it makes sense.
While I have to say that at least at the current situation and the visuals I see the generative design examples are not fully convincing me since they also require often certain manufacturing processes. But I think this is always the case with a new tool making its debut - so I am not seeing this in a negative way.
I am not 100% sure if I can agree with your point that topology optimization in Fusion 360 is only a last step design.
We used this type of solver for various cases ranging from product to also architecture as a structural suggestion when coring out a mass volume body.
The provided solution then was used as a guide to actually design the part.
That is why I am quite excited to have learned that this tool is in Fusion 360 now.
Claas Kuhnen
Faculty Industrial Design – Wayne State Universit
Chair Interior Design – Wayne State University
Owner studioKuhnen – product : interface : design
