Generative Design

The second half of this year has been pretty busy for me.  One area that I have invested a lot of my time has been learning Generative Design.  I still remember being at Autodesk University when Autodesk first started talking about this technology.  They had a bulkhead from an Airbus plane.  They talked about how much weight they were able to remove from just that one subassembly.  I knew then that this would be the future of design.

It has been a few years, but I have really had my first opportunity to really get into Fusion 360's Generative Design process and learn how to perform the design studies.  It really is a powerful technology and even though the studies are done in Fusion 360, I have sought ways to bring this ability to Inventor.  Through this learning and investigation, I have come to discover that Fusion 360's Generative Design process can be used on almost any file.  If you are using Fusion Team, you can use the Desktop Connector to sync your local files to the cloud.  Then use Fusion 360's Any CAD ability to place the Inventor model in a new Fusion 360 design.  If you can't leverage Any CAD, then you can always export and import an STP file.

Regardless of how you get your design into Fusion 360, either by designing right in Fusion 360, using Any CAD, or importing an STP file, you will need to do some sort of setup.  Generative Design has two key geometry definitions, Preserve Geometry and Obstacle Geometry.  Preserve Geometry is a body, or bodies, that need to be part of the final design.  They usually represent key connection points.  Obstacle Geometry is a body, or bodies, that need to be avoided in the final design.  Both of these can be component bodies or bodies modeled specifically for the design study.  You do have the option of creating a Starting Shape, which is a body that represents the shape you want to start with.  This is not a requirement and I don't often define a Starting Shape.

Preserve Geometry

 

Obstacle Geometry

The Connector Obstacle command does a great job of allowing you to define assembly hardware as obstacles.  You can pick a hole and define a bolt, with or without a nut, shown as cylinders.  You also can define a tool clearance, shown as another cylinder, which will ensure you have access to properly assemble your components.

Connector Obstacle

After you have all of the Preserves and Obstacles defined, you can begin defining your Load Cases.  Load Cases are Structural Loads and Constraints that represent different scenarios that your design is going to face.  You can apply static forces, pressure, moments, bearing loads, and remote forces, which were added in November of 2020.

Next comes defining your Objectives and Limits, this is where you can define the objectives for the study.  You have a few choices as to what types of outcomes you are looking for.  The most common is the Minimize Mass with a minimum Safety Factor.

One of the best parts of the Generative Design workflow in Fusion 360 is that it is manufacturing aware, meaning, that we can identify potential manufacturing methods and the study will take those into consideration when generating the outcomes.  We have choices of Unrestricted, meaning it will just generate the best shape possible, Additive, 2 1/2-Axis Milling, 3-Axis Milling, 5-Axis Milling, 2-Axis Cutting, and Die Casting.  Each will have its own specific parameters.  There is also the ability to enable cost estimation for the outcomes.  This enables you to enter the number of pieces you need to make and Fusion will use the aPriori database to also estimate manufacturing cost.

The last criteria you will have to define is the materials.  You can define the potential materials that are being considered for the component.  You can set materials for all manufacturing methods, or you set specific materials for specific manufacturing methods.

After all the setup, you can then Preview the outcome.  This is a good idea because it can help you see if you forgot to include a preserve or obstacle, which has happened to me once or twice.  

Then it is time to run the study.  The study will be done in the cloud.  When Autodesk first introduced this workflow, it cost 25 Cloud Credits to calculate the outcomes, however, they have since removed that cost.  Now the only cost associated with running the Generative Design Study is just a cost of 100 Cloud Credits per outcome that you generate an actual design file from.  The time it takes to fully calculate all the outcomes is a combination of how many manufacturing methods and materials you have chosen.  For me, it usually takes a couple of hours, but the actual time will vary.

As the study outcomes are being generated, you will be able to start looking at the results.  There are different display modes for the results and the left-hand side of the dialog gives you the ability to filter the outcomes of a variety of factors.  One of the newer enhancements is that you will receive recommendations as to which ones are seen as the best possible outcomes.

I could go on and on about filtering and sorting individual results, but the goal would be to export an outcome to a design file.  That would be better as another blog post soon, so this will all for now.  Hopefully, you will be able to leverage this workflow, regardless of which tool you use as your primary design tool.  

If you would like to see more, please watch my recent webinar on how to perform a Generative Design Study on an Inventor model.