Forté: User-Driven Generative Design

What is Forté?

Have you ever wondered how you can design one of those organic-shaped furniture that has both aesthetic and structural appeals? Forté is a tool that can let you simply sketch and generate such designs.

Here is a (toy) example

“The Great Wave off Kanagawa” is favorite painting. Wouldn’t it be great if you can design a reading chair that looks like the shape of the wave?

Using Forté, you simply start by sketching a few strokes overlaying the painting (Fig. 1a). Then you sketch the loads (Fig. 1a, red inks and arrows): where a person will sit and what’s the approximate weight; maybe there’s a light at the tip of the wave; and a shelf on the other end to place a few books . Finally, draw a (blue) line to show that the chair will be placed on the ground.

Figure 1. Using Forté, you can sketch a reading chair design that looks like your favorite painting (a); Forté then generates structures that aesthetically approximate your sketch (bc); a miniature prototype was 3D printed (d).

That’s it. With the click of a button, Forté will generate detailed structural components based on your sketch (Fig. 1b), as well as the loading scenario, that the chair needs to support a person, hang a light, and accommodate a few books. Voilà! Here’s your Kanagawa reading chair design (Fig. 1c). You see a 3D-printed miniature prototype (Fig. 1d). You can also choose to make a real one, as I will show you later down the page.

Here are some more (serious) examples

To start, a pair of high heel shoes made from Forté’s generated structural patterns. The actual physical shoes were 3D printed and are both wearable and functional.

A bike seat.

A pet jumping platform. That’s my youngest chinchilla.

An alternate leg design for a quadruped robot.

Now it’s time for some real furniture. A tea table. The legs were designed using Forté. Everything was cut using a CNC and then assembled.

Now even more seriously real furniture. We made these meeting tables for our new lab space in the HCI Institute at Carnegie Mellon University.

Here’s what our study participants designed …

It’s not fair if we just kept the tool to ourselves. So we recruited 10 participants with various backgrounds and let them play with Forte for about an hour. Here’s what they designed.

Under the hood: topology optimization

Forté is based on a generative design process called topology optimization, which optimally distributes material within a given space in a way that the resultant structural layout has the highest strength.

For example, imagine you give topology optimization a piece of clay and tell it you want a step stool that has four legs touching the ground and should support weights on the top. Topology optimization will test the strength of the clay as if were a four-legged stool supporting those weights, and then it will slightly change the shape in a way that makes it a little stronger, and then repeats the process again until eventually the resultant shape can’t be stronger any more (unless you give it more clay).

Forté puts humans in the loop of topology optimization

Here’s why Forté has gone far beyond the conventional topology optimization.

Three optimization techniques. Once a user sketches a design (say, the robot leg), Forté provides three optimization techniques to generate structures that mimic the sketch.

  • Add structures: adding extra structures to reinforce the user’s sketch, while keeping it as part of the final result;
  • Obtain variations: creating a variation of the user’s sketch that, while different in details, maintains an overall similarity;
  • Optimize within: expanding the user’s sketch and then optimize the internal material layout.

Global similarity control. The user can tune a global similarity value to control how much the optimization is allowed to deviate from the original sketch. You see below how the results differ with high/low similarity values.

Local suggestive edits. The user can also locally refine a generated result. For example, erasing part of the result will trigger the optimization to rerun, and this time it will try not to avoid generating anything where the user has erased before. Likewise, the user can suggestively draw something in the empty space and the optimization will rerun and try to generate structures around that area. You see below how users’ edits influence the optimization.

Visualizing structural strength. To keep the user informed, Forté can always display the current ‘heatmap’ of the structure’s strength.

Summary and take-aways

With Forté, you don’t have to be an industrial designer or a mechanical engineer to make your next piece of furniture.

  • Forté allows you to simply sketch your design and the loading scenario, which is then turned into generated structures optimized to support the specified loads.
  • Instead of sitting there and waiting for the optimization to spit out unpredictable results, Forté lets you interactively control how much the generated structures can deviate from your original sketch, how you want to refine places here and there by adding or removing parts, and you can always see how the strength changes as your design evolves.
  • We have used Forte to make a range of things, including a reading chair inspired by the Kanagawa painting, a pair wearable high heel shoes, a bike seat, robot legs, a jumping platform for my chinchilla, and furniture that is currently being used.

To learn more about Forté, check out our project page. For a more technical experience, you can also download, set up and try out the system here.

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