Max Harris

This week (with the blessing of Prof. Katz), I explored the generative design tools of Dynamo’s sister app, Fusion 360! As a product design major, most of my work is in Fusion 360, which is a CAD application made by Autodesk. Though it has many similarities to Dynamo, its function differs greatly; while Dynamo focuses on architecture, Fusion focuses on product development and assemblies. Through this post you’ll see how this difference percolates down into the generative design space and leads to a similar but unique experience!

Currently Fusion has 3 broad categories of generative design tools: automated modeling, shape optimization, and generative design. They each have a similar workflow and setup, but use computational power to achieve different types of optimization. I tried each of them out and explain will my experience below!

To get accustomed to the tools, I stepped through an example designing a wrench (explained in next section). After I felt comfortable, I used generative design on two other models to test out its capabilities.

In each category I made a variation of the above “adjustable wrench” through following a tutorial. It has two load cases:

1) The left most hex goes onto the hex nut and a handle is placed in the circle, which is used to rotate the wrench. So, when constraining, the inner faces of the left most hex stays constant and there is a 50N load applied to the inner surface of the circle. This is simulating how you could get the most torque out of the wrench.

2) The hex in the middle goes onto the hex nut and a handle is placed in the circle. When constraining, the inner faces of the middle hex stay constant and a 25N force is applied to the inside of the circle. This is simulating the fastest way to rotate the wrench.

The goal of using the following design tools is to minimize the mass of the above shape while maintaining stiffness and stress resistance.

This is the simplest of the Fusion generative suite. It is a relatively new feature (released July 2022) and it sits directly in the design window (second from the left).

The goal of automated modeling is to provide a quick way to create a connection between multiple parts. It does not take loads or constraints into consideration.

I started with the cutouts of each necessary shape on the wrench. Then I clicked Automate and selected the faces I wanted to connect. After running for a little bit, I was presenting with six options and chose the first. I forgot to specify that material could not go OVER the holes, so I used other modeling tools to remove that material.

It definitely is the most basic functionally, but in a pinch or for a quick connection, I can see this being really helpful!

Shape Optimization is in the simulations section of fusion and works by removing unneeded material based on stress.

For this I started by analyzing the stress in the rectangular wrench. Shape optimization targets those low stress areas (the two load cases shared below).

Then I set up my conditions and constraints in the shape optimization space. I specified:

1) Constraints (fixed faces)

2) External loads acting on part (forces)

3) Material of desired solution

4) Desired mass reduction (I chose about 30%, but ended up picking a result closer to 40%)

I ran the study and got a shape close to the result below! However the shape was jagged and rough on the edges. So, I took that shape, exported it into the design shape and traced the edges to make a more smooth profile. Finally, I ran a stress test on it below, and it has some higher areas of stress, but nothing that would break it, and it’s mass is 40% reduced!

However while exploring, my favorite BY FAR was generative design! It has its own tab in fusion and creates such unique shapes. Instead of starting with the big shape and carving out like in shape optimization, I started with the shapes for each hole separated. First, I applied the constraints and loads in the same way as above (the lock icons represent fixed faces and the arrows represent forces). However, after that generative design branches into a unique space.

The three models above are green because I made them “preserved geometry”. This means that any design generated has to keep those shapes in it. You can also set obstacle geometry which is area Fusion CANNOT place material. I didn’t use obstacles for this one, but I did for the project below!

After setting your geometry you can choose parameters (similar to Dynamo) and you will get a solution for each parameter pair.

1) Material. You can add multiple materials to the study and Fusion automatically sets the properties, which could lead to different solutions. For all of mine I chose Aluminum and Tough Resin (for 3D printing).

2) Objective. You can either aim to minimize mass or maximize stiffness. I always chose to minimize mass because that’s how you get the coolest results (for my applications).

3) Safety factor. I always chose 2.

4) Manufacturing. Here is where you can really rack up the options. Each manufacturing pathway chosen will give you a different option becuase they each have to be made differently. These are the following options: Unrestricted (will not consider manufacturing), additive, milling, 2 axis cutting, die casting. I always chose unrestricted and additive because those are ideal to 3D print, however sometimes I also chose 2-axis just in case I wanted to laser cut/mill.

After that you’re ready to run your study! Here are some of my results below. The left is 2-axis cutting, the right is unrestricted.

After walking through the wrench example and getting comfortable with the functions, I wanted to design something from scratch. Recently I’ve been playing my kalimba (pictured below) a lot, so I decided to design a stand for it.

I started by creating a base shape and a backing shape that were unconnected. Then, I went into the generative design space and applied loads/constraints to models (shown left). I added the red obstacle shape (right) to ensure no material would be generated over the flat part of the stand.

After choosing materials (aluminum & Tough Resin), objectives (Minimize mass), safety factor (2), and manufacturing methods (unrestricted & additive), I ran the study! It took about an hour to complete, but when it finished, I was so excited by the result!

It created this natural, tree-esque shape that seamlessly molds into the back of the stand. Someone once told me a lot of generative design looks “natural” because nature is the best engineer when designing for mass efficiency, which is definitely the case here. Similar to dynamo, you can compare models side by side before picking your ideal option. The other model it generated was a little thicker (which I didn’t love), so I picked the above.

It also has a couple different viewing modes available before you choose including model view, transparency, and stress analysis.

Finally, I exported my model to the design space! Next step is to 3D print it, which I will do this upcoming week. I’ll post the updates here when it’s done (Its a long print, so it might take a while :)

I am so happy I got to try out Fusion generative design this week! I’ve always seen the products and been so amazed, but never really understood how to get there. After putting in the time and walking trhough the tutorials I feel pretty confident in my ability to set up a scenario that will produce good results. I don’t know what it is about the nature-y feel but it hits me to my core. When that image of the stand came up, I audibly gasped. That feeling is what I am constantly searching for while I design and to be able to get that on CAD so simply, is just awesome. Thanks for letting me explore and add a great new tool to my toolkit!