Stoffwechsel and 3D Printing in Architecture

semper oper dresden image taken at night
The Semper Oper Dresden, Oliver Haler.

Gottfried Semper was the architect for a number of important buildings such as the Dresden Opera and the ETH Zurich building. He also is jointly responsible for the Kunsthistorisches Museum, Naturhistorisches Museum and the Burgtheater in Vienna.

two sculptures, both busts the left is colored the white marble.
Comparison between a polychrome bust and one as we now can see without color.

As well as an architect he was a theorist and researcher. Capable of original thought and an iconoclast he was a key proponent of polychrome architecture and statues in antiquity. At the time theorists and researchers refused to believe that Roman and Greek statues were in reality painted in many colors to be as lifelike as possible.

images showing colored and white roman statues
Statues as we imagine them and how they were.

Ancient Roman and Greek buildings were also very colorful. Still to this very day the art and architecture of Rome and Greece is imagined to be very sedated and white whereas in actuality it was a riot of colors. Even contemporary movies and shows featuring Rome and Greece often imagine all the surfaces to be a calm and anaemic white.

A panel from a Sarcophagus showing how it was originally colored
Alexander’s Sarcophagus, Sidon.

This hampers our understanding of the Romans and Greeks. We can’t help but see them as somehow clinically detached aesthetes. On some level, Rome will always feel like some ancient space station where “great men” calmly walked on every street corner. White, clean, scarcely populated and quiet. Royal slippers side by side soft clicking set to a measured debate. The riotous multicultural chaos where people of every hue mingled (albeit not all equally, but this at least was a theoretical possibility for many) is unimaginable for many of us. Fascists often borrowed Roman grandeur replete with the clean and “pure” lines to give power to their rallies or buildings. It is unclear to what extent their borrowing was driven by pure esthetics or by the mistaken belief that ancient Rome was some kind of white Aryan populated operating theatre.

an image showing a polymer stencil that can make concrete floors look like bricks
This faux brick stencil can be considered a good example of a product that recreates past patterns.

In addition to some very significant works in paper and stone, many of Semper’s ideas have always intrigued. The one that grabbed me the most is stoffwechsel. Stoffwechsel is the idea that an object’s purpose will shine through, throughout successive changes in the material. The surface of an object could have patterns, shapes or texture of some kind. A new manufacturing process would then come of age. This process would not need these vestigial patterns, but they would be included anyway.

A wall showcasing different kinds of brick veneer, thin stone patterns that make things look like actual stone walls.
Brick veneer lets you apply a brick or stone pattern to existing concrete or other walls.

The classic example of this is wall coverings. Previously carpets were used as wall dividers in houses. Later on, new building techniques saw walls being used. These walls were then covered in tapestries to provide for isolation while simultaneously evoking the same look of previous rooms. In a later period, 16th-century wealthy people replaced wallpaper with floor to ceiling paintings. Then stone walls where developed and these were often covered in wallpaper. This wallpaper gave a blank plastered wall similar and familiar geometric patterns and warmth as the previous generation tapestries. Later on, we see bricks get replaced (in some cases) with concrete. The concrete is however given patterns to appear to look like bricks.

The Google Material Design Save Icon. This is an example from graphic design, where the old behaviour of storing files on a removable disk still lives through representations of that disk in some software programs.

Gottfried Semper’s theory of stoffwechsel is not widely referenced today (Please do correct me if I’m wrong, I have rarely come across him). Although in some quarters his work is revered more contemporary architects have replaced him in the collective mind’s eye. By firmly rooting architecture as an (at least partial) expression of communities driven by ritual and habit, Semper firmly roots architectural practice in history. By knowing him, we see architecture a little less as “great men drawing” and much more as a practice driven development within society as a whole. In Semper’s architecture, there are constraints, communities, practices and solidified ideas contained within a specific time. 

As we, hopefully, come down a little from our pedestal starchitect world. A more humble and humanistic view of architecture such as Semper’s would in my mind be more fitting.

Products such as Marmoleum (made from jute, wood flour and linseed oil) have patterns that evoke parquet floors which in turn remind us of wood plank floors which in turn remind us of wood beam covered floors who in turn evoke homes made of wood entirely.

I’ve always felt that some starchitects made buildings to build their portfolios rather than homes or spaces that worked for the customer or the public. The result is an architecture that is pure Ego over function. Architectural awards have always struck me as analogous to giving surgeons points for the beauty of the scars they leave behind. Yes, it may very well matter, but the health of the patient matters more. By rooting architecture as a product of time and place while seeing patterns of vestigial structures repeat themselves through different materials and technology paradigms Semper gives us an architecture that to me feels real and expressive. Materials and history to a certain extent dictate form. While at the same time, to me, it feels comforting that the patterns and practices that surround us are lines of history signalling past technological shifts and the familiar. The room I’m in is not as a space drawn by a “macher” but rather a space communicating its current place and past patterns. It is as if every building is not only a statement but also a timeline showcasing past paradigms and shapes back to the beginning of building itself.

On the iPhone 7 Apple replaced the physical mechanical home button with its taptic engine. Once pressed the taptic engine moves the phone so the person gets a sensation of pressing a button even though there is no button. This complex part replaces the button assembly and allows for better weather sealing on the phone. In this example a complex new technology has been developed precisely to reinfornce an old behavior.

Some conservators removed pigment and paint spots from Roman and Greek statues. So convinced were they that these were meant to be white that they took scalpels to historical evidence so that the statue would conform to their idea of them. We still do this. In 3D printing houses, we are trying to recreate past shapes with new technology. A drawing and idea become the jumping off point to developing a technology. Brick houses, ideas and patterns are being made with 3D printing. The old paradigm is still in the driving seat esthetically, as is the old way of doing things. There are a lot of renderings and overclaim in the 3D printing houses business, and not a lot of actual buildings. Stoffwechsel is not just now driving a wall covering but firmly in the driving seat of the overall design with brutalist ideas and fanciful idiocy now possible with new technology. Rather than look at improving functionality or making better homes silly drawings are being printed. Some startups do seem focussed on functionality and technology, but most look for something space aged and then run with that.

Essentially we should make the Pantheon.

If we honestly looked at how a 3D printed building could be made in the least expensive way possible we would then have to change our ideas to match reality. The most optimal building would be a self-supporting dome. In this way, no supports or support materials would be needed, and prints would be quick, and all be in one layer with no lifting or retraction required. For many types of building, design retraction is not needed, and it is precisely these forms that can be printed the quickest, safest and cheapest. Doors and windows could be cut out of the dome form after the fact for example. Alternatively, a complete technical core of a building could be made offsite and lowered through the oculus. In that way, this cylinder could contain all of the water, electricity and other technical parts of the home and even be serviced or replaced centrally. Is this the be all end all idea of Additively Manufactured Architecture? I hope not, but it is at least an idea grounded in the process and limitations of the process that hopes to be efficient.

Made from clay the Musgum people of Cameroon make these Obo homes. The shape is an efficient catenary arch. The building has vents in it that keep occupants cool by circulating air. The spare, efficient shape has no waste on it, even the outside decoration is made to be foot and handholds so that the building can be repaired.

Lack of process understanding by architects and an idea lead approach is causing people to have to develop completely unnecessary features in 3D printers and unnecessarily raising the cost of 3D printing. Please let’s let the engineers run it this time?

When I used to live in Bahrain I was amazed that the most comfortable places to be where the traditional houses in Muharraq. They had thick walls to keep out the heat and were pleasantly cool due to the wind towers that guided wind through. This in contrast to all the other buildings which were freezing and clammy because of the air conditioning. The old buildings were designed with constraints in mind.

Design for Additive Manufacturing and optimising design choices from the start for 3D printing is where smart companies are now placing their efforts. Designing with constraints and advantages in mind is how rewards can be reaped. Its as if we’ve designed a roller ball pen and everyone is obsessed with making it look and work as a pencil does. I love stoffwechsel as a concept for viewing ceaselessly into the past, but it should not guide architecture’s future.

Desktop FDM 3D Printers Will Win in the Manufacturing of End Use Parts

A 3D Print in Matte Grey of an FDM part.
A Facilan C8 3D Printed Part by 3D4Makers.
  • Over 500 OEMs and over a 400 3D printing filament vendors have joined the desktop FDM 3D printing market.
  • One that has now seen the sale of over one million desktop FDM 3D printers worldwide.
  • Desktop FDM systems have developed very quickly with reliability, repeatability and print quality improving rapidly.
  • FDM is the most vibrant, competitive and fastest developing area of 3D printing
  • Touch screens, bed levelling and dual extrusion, are all emerging features. More companies are developing 3D printing software, and bulk filament prices are cratering.
  • Rapid shifts in this market have made open FDM desktop systems a viable contender for manufacturing.
  • With reliability and part quality improving, desktop FDM has gotten close (in some areas) to the output from industrial Additive Manufacturing systems.
  • For B side parts, tough parts and strong parts FDM is now a viable solution for manufacturing at scale using 3D printing.
  • Automotive, aerospace, industrial, machinery and manufacturing industries are using thousands of desktop type systems to manufacture parts.
  • Companies who wish to lead in manufacturing the future are now deploying hundreds of systems in arrays to produce end-use parts.
  • With high dimensional accuracy and good part, strength manufacturers are also finding that using desktop FDM to manufacture gives them the lowest part cost in 3D printing.
  • If one includes finishing and post finishing the part costs are much lower in desktop FDM than with other technologies.
  • There are of course exceptions, but as a general rule, a Kilo of desktop 3D printed parts can cost between $12 and $50 in desktop FDM compared to ranges of between $100 and $1000 per Kilo for other technologies.
  • Additionally FDM materials and material properties are often more familiar to them than the rather more exotic SLA (stereolithography, vat polymerisation) and SLS (selective laser sintering, powder bed fusion) materials.
  • The fact that the desktop FDM systems market is open and lets people use whichever material they would like is the main reason why I advise clients that manufacturing with desktop FDM is an excellent alternative to other technologies.
  • Materials developments are accelerating with flexibles, filled materials and custom materials being developed much more readily and inexpensively for desktop FDM.
  • By providing a low kilo price per part, a good time to part and OK looking parts, desktop FDM is winning in manufacturing.
  • In medical SLS still reigns supreme, indirect and smooth parts are still governed by SLA while for many individual parts and applications closed ecosystems are still more desirable.
  • In general manufacturing applications, however, it is FDM that is quietly gaining the upper hand.
  • Whereas some of my colleagues (and wannabe general consultancies without any 3D printing knowledge) believe in closed systems, I believe in the crazy, tempestuous world of desktop FDM.
  • A friend of mine opined that he thought that desktop FDM was dead. I was thoroughly surprised by this.
  • The rollercoaster is just picking up steam, and it will get crazier before it gets saner.
  • But, tens of thousands of end-use parts are being made on desktop FDM systems and used in industry at scale today.
  • I believe that in general manufacturing of end-use parts it is desktop FDM that will win out over other technologies.

Ecobibots: 3D Printed Soft Robots Will Hug You and you will Dispose of Them

A 2004 paper by Hod Lipson and Evan Malone was what inspired me to work in 3D printing. The two researchers later showed us that one could make a simple 3D printed robot with 3D printed batteries and actuators. They also developed the open source Fab@Home desktop printer in 2007. Both are a huge inspiration to me so when some of Hod’s papers started to veer off into soft robotics and resilient machines I took a long hard look at the emerging field.

And…I didn’t get it. Around 2010 I concluded that this was a lot of grant-giving for grant giving’s sake stuff. The only real useful application I could see were 3D printed pneumatic soft grippers.  Super Releaser has an excellent history of soft grippers here. Soft grippers could make robots more capable of interacting with people and the world and I saw that as a very interesting development. Hod and others were looking to make the entire robot a soft robot, however. Soft bodies, soft actuators, soft sensors, soft everything. Some of the stuff seemed outlandish with chemical reactions powering pneumatic assemblies and many bioinspired robot fish. It didn’t help that most of this soft robotics stuff initially looked a bit hokey and contrived.

A Soft Robotics Octopus arm also called a muscular hydrostat is a bionspired arm using Shape Memory Alloys. It has been made by the team behind the Octopus Integrating Project that aims to replicate an entire octopus. 
An Animated GIF of a Shape Memory Alloy Soft Robotics Octopus Arm
The Shape Memory Alloy muscle is a copy of the Octopus’ muscle and has been used to move the arm and grasp objects. Shape memory materials are increasingly being 3D printed as well.

It took me years to come to grips with soft robots. I was sceptical for a very long time. I kept reading paper after paper. YouTube videos emerged as well as soft robotics GIFs but still, I thought that this was a detail or a fad. Then I had a thought: what if all the Sci-Fi robots were just silly imaginings made by authors looking to entertain? What if we were wasting billions developing humanoid robots that can walk up stairs just because those are in the movies? That would be insane right? Imagine there were billions of dollars in research funding going towards making Quidditch happen? All of this humanoid robot research is just plain silly. If countries were building a Death Star people would ask questions right? If billions were being spent on AT-AT walkers people would wonder, protest? But, whole industries, countries and tens of thousands of researchers are making C3PO happen and we don’t bat an eye? Look, I want real lightsabers as much as the next guy but we need to be rational. And this whole humanoid robot thing is just like AT-AT walkers and light sabres: cool but stupid, infeasible and unnecessary. It would be cheaper to make a new robot for every floor rather than one that could walk upstairs. Whats the business case for humanoid robots? Why are we developing them?

Why would you give a robot a knife? And why would you need a knife for Oreos?

What if we dispensed with the humanoid robot idea altogether and instead think of functional robots designed for sets of tasks. What if we dropped the one universal Commander Data robot and instead thought of small cheap disposable robots that would live not in a novel but in the real world? Disposable bots, I called them in my mind. Not multi-million dollar Asimos teeteringly kicking a ball but cheap inexpensive robots that would disappear or be thrown away as soon as their task has been completed. Not billions spent making a robot that could walk like a human or some terrifying nightmarish Boston Dynamics Hound of Baskerville’s killbot but rather a descendant of the cheap omnipresent consumer electronics that surround us. If we see how fast consumer drones are developing and assume that chips and sensors will always get cheaper then what will the $5 robots of the future look like? Remember those cheap little RC helicopters that you could buy for $15 that’s the technology paradigm that interests me with regards to robotics. Below we can see a robot fish. This particular one was created by a team at MIT CSAIL as part of their soft robotics research. It describes several methods for making soft robots, in particular, a Fluid Elastomer Actuator. The design is ingenious but as we can see the multitude of fabrication steps required as well as the different materials and processes will make this cost prohibitive.

A diagram showing the power system that drives the ribbed soft hydraulic actuator.


How would we be able to make the robot equivalent of Crocs? I always like to use Crocs as thought experiment fuel. The reason is that I could have never have come up with the idea for Crocs. The only way I could have come up with Crocs, was if the starting question is “how can I make the world’s cheapest shoes?” Or how can we make the least expensive shoes imaginable using molded closed cell foam (and later TPU)?  So if we Crocsify robots we come up with a robot that would be made in one single production step out of the fewest number of parts or materials in that production step out of inexpensive materials. That one step would approximate the functionality created through many steps and materials in current devices. What would fit that technology path and outperform current technology at lower cost? And then, only then, did I go “Oh Fuck, soft robotics is totally going to be a thing.” 3D print all the robots, recycle robot, reprint new robot. No nightmare fuel Boston Hellhound but a purposeful efficient cheap printable soft robot. No national prestige project violin playing nonsensebot but rather you and I 3D printing robots at home.

Tolly is a 3D printed soft actuator that works on compressed air filling chambers. This was made essentially in one step on a Stratasys Objet Polyjet machine.

I now understand that bioinspiration is a good thing and that in order to mimic nature more perfectly soft parts are required in many areas. I also understand that a flexible and soft robot could have very different use areas where it could outperform a rigid counterpart. I’m excited by self-configurable robots that can adapt to tasks or circumstances. It would be a breakthrough to have a robot powered by heat or through photosynthesis. The idea that robots would scavage for their own energy or be permitted to morph continually would be interesting as well.

The below robot uses 3D printing for circuits and a microfluidics.

Small robots in the bloodstream, unobtrusive robots for spying, cobots that are near people all the time could all benefit from soft robotics. Probably swimming robots that mimic fish will be far more efficient than conventional underwater robots and maybe robots that fly like birds or insects will be as well.

The Wyss Institute jumping robot uses 3D printed gradient materials.

Nature takes a razor to fat. Shapes, structures and creatures in the natural world are very efficient. 30 Kilo of blubber is enough to power a Great White Shark for 11 days. Canada Geese eat around 1.8 Kilo of grass per day. A Goose can fly, is biodegradable and its waste is a Kilo of carbon per day. A soft robot design coupled with a biological energy creation mechanism could lead to a very efficient class of robot indeed. This class of robots would be power efficient and also environmentally efficient as well. A bioinspired design may make its form more efficient but a biological or chemical “engine” will also make the robot very efficient to operate. The resulting design will also be efficient in terms of its waste and end of life disposal as well. So not biomimicry to come up with a form but biomimicry across the lifespan of the device. The resulting robot would be ecological and bioinspired, soft and efficient. They would use bacteria, sunlight or harvesting to find energy. We could call them ecobibots. This would be a huge step forward in robotics development.

Ideonella Sakaiensis is a bacteria that can degrade PET plastic. Would this not be a good thing to use as fuel for a robot?

Bacteria are now being engineered to feed off waste or things such as methane. For a methane-rich environment, a methane harvesting soft robot could be very efficient. Want a sea patrol robot then perhaps it could feed off algal blooms? Want a robot for in the desert then maybe the huge fluctuations in temperature there could be used to power the robot via a kind of Stirling Engine.

Regular temperature differences during the night and day could also be used to regulate or power chemical reactions in the robot to power it. Have you heard of Click Heat? It’s a sodium acetate heat pack. You click it and a reaction heats the pack, afterwards, you can boil it and then use it again. Wouldn’t that be a nifty kind of chemical mechanism to power a robot?

A diagram of an Atmos clock. 1 is the expansion chamber.

The Atmos is a clock by Jaeger Le Coultre that can perhaps work indefinitely. The Atmos works on temperature changes. A chamber filled with ethylene chloride gas in the clock expands and contracts in response to temperature fluctuations in your room. Expansion and contraction in turn wind the clock’s mainspring. Imagine a soft robot powered with a similar mechanism. Wifi signals abound and there are devices being made that let people harvest energy from these devices. Hydrothermal vents are surrounded by chemosynthetic bacteria that turn sulphur/hydrogen sulphide into food to sustain ecosystems on the ocean floor. Could we perhaps combine soft robots with chemosynthesis to obtain nutrients for the robot or indeed organic material that it could use to improve itself? And could we then pretty please use carbon dioxide as an input material?

The combination of new ways of generating power with soft robotics to create more efficient robots would mean taking biomimicry/biomimetics and using it to not optimize form but optimize energy usage. To make a soft robotics Asimo will take quite some time and a series of technological breakthroughs. But, what if we just need a soft robotics Roomba? Does that thing really need all those optics, batteries and a plethora of parts? What if we just had a Squeegee that gradually moved around our livingrooms picking up dust? No sensors, no chips just a Squeegee that moves by itself. Once a month you wash it under the sink.

The Golem Project was Hod Lipson and Jordan Pollack was a 2000 project that showed the automated fabrication and automated design of robots. The project also worked according to evolutionary principles.

In other applications: what if robots were cheaply spread around an oil spill and evolved in keeping with the task. What if these evolutionary and adaptive robots were easy to recycle? You could just continually recycle the ones that are not performing and let the others carry on. Many soft robots are being made through 3D printing. 3D printing continues to expand to make TPU, PCL, PA and other flexible materials possible. In other developments circuits and conductive materials can also be printed. 3D printing of magnets, technical ceramics and actuators also are being improved. Several soft robots have been entirely or almost completely 3D printed. 3D printing is the most obvious assembly and manufacturing technology for soft robotics. These technologies will continue to reinforce themselves and improve apace. Ever since my thought experiment I’ve become a true believer in soft robotics. Of course, this has to do with the things I’ve mentioned above but most of all with the fact that ecobibots, soft robots or their equivalents will be cheap.

This soft gait robot was also made using 3D printing.

Soft robotics has the potential to make robots made in few manufacturing steps out of very inexpensive materials such as polymers. They’ll use fewer metals and less expensive materials and less material overall. Soft robotics has the potential to make robotics cheap. True ecobibots that would additionally procure their own power and be recyclable.  In essence, you would have disposable robotics which would also lower costs. I finally believe in soft robotics but not because it could be revolutionary but because it can be cheap. If we look at developments in 3D printers and 3D printing materials soft robots could also be manufactured by the hundreds of thousands of desktop 3D printer operators worldwide and that would be very exciting indeed.

This shape memory coil and 3D printed soft robot was optimized for low cost manufacturing.

So far, however, most soft robots are conceptually amazing but seem to serve no purpose other than to demonstrate soft robotics. In order to really let soft robotics hit home, a useful soft robot would have to serve some purpose. It should also seem like a complex but easy to explain breakthrough. This after all, with a few million in PR money, was how the “3D printing revolution” happened. So we need a soft robotics demonstrator that would play well on Buzzfeed and top ten lists. Sad perhaps, but without adequate demonstrators of the capability of this technology, will remain dormant. Real wide interest will come once media can convince people that this is something relevant for the consumer right now. Once this occurs then we can speak of a Soft Robotics Revolution. So what say you? Let’s have at it? I’m a believer now, just registered the domain name: