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Nov 13 2012

To follow up on the post Fabricating Nature let us consider what we mean by 'man-made' objects. Clearly, they are objects that are produced by human effort through a process of design and fabrication, rather than through a process of evolution and natural growth. But what if we start to blur the distinction between objects that we produce and objects that are produced directly from nature. What if we could produce objects that aren't the clunky things we have now, but ones which appear to have been grown. While it won't change the dictionary definition, it just might change our perception of manufacturing.

One of the ideas that our CTO and joint founder Turlif has mentioned in some of his talks is the idea of a Physical Turing Test. The traditional Turing Test was proposed by Alan Turing as a way of testing for artificial intelligence. Here a machine was said to pass if a human conversing with it in a blind test thought that they were talking with another human being. The idea of the Physical Turing Test is that we test objects against nature. If a human believes that a man-made object was actually made by nature, then the object passes.

An amusing example of this is in the Dilbert cartoon on 3D printing. Here, the 3D printed object was mistaken for the actual character, so physically the object passed the test. While mistaking a constructed object for a human being might seem unlikely, waxworks have always been popular not to mention the field of robotics. In the distant future, who knows – perhaps the traditional Turing test and the physical Turing test will one day need to be combined...

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Nature is unbelievably complex. Animals and humans have evolved in this world without in-built digital systems. Our minds have evolved in ways that allow us to make sense of our environment, so that we can abstract and categorize the things that we encounter and experience. As such, we have an in-built tendency to represent the world in terms of simple, clearly identifiable boundaries of space and objects. When we create objects ourselves, we continue to follow this path without even realizing it. Traditional manufacturing and design assumes that each object, or each independent part of a larger object, is made of a single homogeneous material. This makes human-made objects clearly stand apart from nature. A tree, for example, is not made from a single material and nor does it have 'parts' that are as easily discernible as we would think - if we look up close we can see that roots blend into the trunk, which blends into branches which blend into twigs, which blend into leaves. Our abstractions are useful for recognition and categorization, but they do have limitations when it comes to creating or recreating complex objects like this.

Historically then, we've interacted with nature through powerful but reductive simplifications and approximations - the way we look at it, the way we model it and the way we attempt to reproduce it. Cheap computing power is now extending our capabilities, putting us in a far better position to understand the complexities of nature. We have better control over matter and can design and fabricate a whole new class of human-made objects. These objects offer more localized, dynamic, sustainable and natural interactions with the world. Unfortunately, we've hit a stumbling block. The current generation of digital design and fabrication systems have failed to fully capitalize on the raw computational power that is available to us. We still can't create objects that offer a comparable wealth of detail, complexity and combination of materials that we find in nature. Here is an example of how a typical user might model a watermelon using 3D modeling tools and a real watermelon. There is little to compare other than the rough outside shape. How can we truly represent a slice of watermelon digitally?

Let us take a very basic example, one that is even human made, a glass marble. Marbles are simple children's toys, but how can we exactly model their construction?

The only real 'surface' here is the outer shape, but modelling it with polygons will always leave it faceted. Perhaps we can try to overcome this inaccuracy and using a parametric surface, but can we efficiently represent the minute chips made by numerous games of marbles? Still, a spherical surface won't allow us to define what's inside. Perhaps each of those different colors could be a separate part? If we look closely at the swirls we can see that they don't have sharply defined edges. The colors mix and blend together throughout the interior. Our traditional approach of modelling with surfaces falls apart completely. Our entire approach is wrong because this is a problem that requires real volumes with no neatly defined 'parts'.

Is this a fair example? Would anyone actually want to recreate a watermelon or 3D print a glass marble? Perhaps not, but what about a human organ such as a kidney. That's also a challenging volumetric problem and one that would be of huge benefit if we could design and fabricate them as required.

So, the way we think about the world allows us to make sense of it, but doesn't necessarily let us reproduce it. Existing digital systems have followed our natural way of thinking and have led us to an impasse. They are imprecise and fundamentally incapable of accurately representing real objects. If we want to move forwards, we will need to take a very different approach.

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