Tag Archives: 3-D printing

The wonder of movement in 3D

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Shades of Eadweard Muybridge (English photographer who pioneered photographic motion studies)! A September 19, 2018 news item on ScienceDaily describes the latest efforts to ‘capture motion’,

Patriots quarterback Tom Brady has often credited his success to spending countless hours studying his opponent’s movements on film. This understanding of movement is necessary for all living species, whether it’s figuring out what angle to throw a ball at, or perceiving the motion of predators and prey. But simple videos can’t actually give us the full picture.

That’s because traditional videos and photos for studying motion are two-dimensional, and don’t show us the underlying 3-D structure of the person or subject of interest. Without the full geometry, we can’t inspect the small and subtle movements that help us move faster, or make sense of the precision needed to perfect our athletic form.

Recently, though, researchers from MIT’s [Massachusetts Institute of Technology] Computer Science and Artificial Intelligence Laboratory (CSAIL) have come up with a way to get a better handle on this understanding of complex motion.

There isn’t a single reference to Muybridge, still, this September 18, 2018 Massachusetts Institute of Technology news release (also on EurekAlert but published September 19, 2018), which originated the news item, delves further into the research,

The new system uses an algorithm that can take 2-D videos and turn them into 3-D printed “motion sculptures” that show how a human body moves through space. In addition to being an intriguing aesthetic visualization of shape and time, the team envisions that their “MoSculp” system could enable a much more detailed study of motion for professional athletes, dancers, or anyone who wants to improve their physical skills.

“Imagine you have a video of Roger Federer serving a ball in a tennis match, and a video of yourself learning tennis,” says PhD student Xiuming Zhang, lead author of a new paper about the system. “You could then build motion sculptures of both scenarios to compare them and more comprehensively study where you need to improve.”

Because motion sculptures are 3-D, users can use a computer interface to navigate around the structures and see them from different viewpoints, revealing motion-related information inaccessible from the original viewpoint.

Zhang wrote the paper alongside MIT professors William Freeman and Stefanie Mueller, PhD student Jiajun Wu, Google researchers Qiurui He and Tali Dekel, as well as U.C. Berkeley postdoc and former CSAIL PhD Andrew Owens.

How it works

Artists and scientists have long struggled to gain better insight into movement, limited by their own camera lens and what it could provide.

Previous work has mostly used so-called “stroboscopic” photography techniques, which look a lot like the images in a flip book stitched together. But since these photos only show snapshots of movement, you wouldn’t be able to see as much of the trajectory of a person’s arm when they’re hitting a golf ball, for example.

What’s more, these photographs also require laborious pre-shoot setup, such as using a clean background and specialized depth cameras and lighting equipment. All MoSculp needs is a video sequence.

Given an input video, the system first automatically detects 2-D key points on the subject’s body, such as the hip, knee, and ankle of a ballerina while she’s doing a complex dance sequence. Then, it takes the best possible poses from those points to be turned into 3-D “skeletons.”

After stitching these skeletons together, the system generates a motion sculpture that can be 3-D printed, showing the smooth, continuous path of movement traced out by the subject. Users can customize their figures to focus on different body parts, assign different materials to distinguish among parts, and even customize lighting.

In user studies, the researchers found that over 75 percent of subjects felt that MoSculp provided a more detailed visualization for studying motion than the standard photography techniques.

“Dance and highly-skilled athletic motions often seem like ‘moving sculptures’ but they only create fleeting and ephemeral shapes,” says Courtney Brigham, communications lead at Adobe. “This work shows how to take motions and turn them into real sculptures with objective visualizations of movement, providing a way for athletes to analyze their movements for training, requiring no more equipment than a mobile camera and some computing time.”

The system works best for larger movements, like throwing a ball or taking a sweeping leap during a dance sequence. It also works for situations that might obstruct or complicate movement, such as people wearing loose clothing or carrying objects.

Currently, the system only uses single-person scenarios, but the team soon hopes to expand to multiple people. This could open up the potential to study things like social disorders, interpersonal interactions, and team dynamics.

This work will be presented at the User Interface Software and Technology (UIST) symposium in Berlin, Germany in October 2018 and the team’s paper published as part of the proceedings.

As for anyone wondering about the Muybridge comment, here’s an image the MIT researchers have made available,

A new system uses an algorithm that can take 2-D videos and turn them into 3-D-printed “motion sculptures” that show how a human body moves through space. Image courtesy of MIT CSAIL

Contrast that MIT image with some of the images in this video capturing parts of a theatre production, Studies in Motion: The Hauntings of Eadweard Muybridge,

Getting back to MIT, here’s their MoSculp video,

There are some startling similarities, eh? I suppose there are only so many ways one can capture movement be it in studies of Eadweard Muybridge, a theatre production about his work, or an MIT video the latest in motion capture technology.

A 3D printed ‘living’ tattoo

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MIT engineers have devised a 3-D printing technique that uses a new kind of ink made from genetically programmed living cells. Courtesy of the researchers [and MIT]

If that image isn’t enough, there’s also a video abstract (I don’t think I’ve seen one of these before) for the paper,

For those who’d still like to read the text, here’s more from a December 5, 2017 MIT (Massachusetts Institute of Technology) news release (also on EurekAlert),

MIT engineers have devised a 3-D printing technique that uses a new kind of ink made from genetically programmed living cells.

The cells are engineered to light up in response to a variety of stimuli. When mixed with a slurry of hydrogel and nutrients, the cells can be printed, layer by layer, to form three-dimensional, interactive structures and devices.

The team has then demonstrated its technique by printing a “living tattoo” — a thin, transparent patch patterned with live bacteria cells in the shape of a tree. Each branch of the tree is lined with cells sensitive to a different chemical or molecular compound. When the patch is adhered to skin that has been exposed to the same compounds, corresponding regions of the tree light up in response.

The researchers, led by Xuanhe Zhao, the Noyce Career Development Professor in MIT’s Department of Mechanical Engineering, and Timothy Lu, associate professor of biological engineering and of electrical engineering and computer science, say that their technique can be used to fabricate “active” materials for wearable sensors and interactive displays. Such materials can be patterned with live cells engineered to sense environmental chemicals and pollutants as well as changes in pH and temperature.

What’s more, the team developed a model to predict the interactions between cells within a given 3-D-printed structure, under a variety of conditions. The team says researchers can use the model as a guide in designing responsive living materials.

Zhao, Lu, and their colleagues have published their results today [December 5, 2017] in the journal Advanced Materials. The paper’s co-authors are graduate students Xinyue Liu, Hyunwoo Yuk, Shaoting Lin, German Alberto Parada, Tzu-Chieh Tang, Eléonore Tham, and postdoc Cesar de la Fuente-Nunez.

A hardy alternative

In recent years, scientists have explored a variety of responsive materials as the basis for 3D-printed inks. For instance, scientists have used inks made from temperature-sensitive polymers to print heat-responsive shape-shifting objects. Others have printed photoactivated structures from polymers that shrink and stretch in response to light.

Zhao’s team, working with bioengineers in Lu’s lab, realized that live cells might also serve as responsive materials for 3D-printed inks, particularly as they can be genetically engineered to respond to a variety of stimuli. The researchers are not the first to consider 3-D printing genetically engineered cells; others have attempted to do so using live mammalian cells, but with little success.

“It turns out those cells were dying during the printing process, because mammalian cells are basically lipid bilayer balloons,” Yuk says. “They are too weak, and they easily rupture.”

Instead, the team identified a hardier cell type in bacteria. Bacterial cells have tough cell walls that are able to survive relatively harsh conditions, such as the forces applied to ink as it is pushed through a printer’s nozzle. Furthermore, bacteria, unlike mammalian cells, are compatible with most hydrogels — gel-like materials that are made from a mix of mostly water and a bit of polymer. The group found that hydrogels can provide an aqueous environment that can support living bacteria.

The researchers carried out a screening test to identify the type of hydrogel that would best host bacterial cells. After an extensive search, a hydrogel with pluronic acid was found to be the most compatible material. The hydrogel also exhibited an ideal consistency for 3-D printing.

“This hydrogel has ideal flow characteristics for printing through a nozzle,” Zhao says. “It’s like squeezing out toothpaste. You need [the ink] to flow out of a nozzle like toothpaste, and it can maintain its shape after it’s printed.”

From tattoos to living computers

Lu provided the team with bacterial cells engineered to light up in response to a variety of chemical stimuli. The researchers then came up with a recipe for their 3-D ink, using a combination of bacteria, hydrogel, and nutrients to sustain the cells and maintain their functionality.

“We found this new ink formula works very well and can print at a high resolution of about 30 micrometers per feature,” Zhao says. “That means each line we print contains only a few cells. We can also print relatively large-scale structures, measuring several centimeters.”

They printed the ink using a custom 3-D printer that they built using standard elements combined with fixtures they machined themselves. To demonstrate the technique, the team printed a pattern of hydrogel with cells in the shape of a tree on an elastomer layer. After printing, they solidified, or cured, the patch by exposing it to ultraviolet radiation. They then adhere the transparent elastomer layer with the living patterns on it, to skin.

To test the patch, the researchers smeared several chemical compounds onto the back of a test subject’s hand, then pressed the hydrogel patch over the exposed skin. Over several hours, branches of the patch’s tree lit up when bacteria sensed their corresponding chemical stimuli.

The researchers also engineered bacteria to communicate with each other; for instance they programmed some cells to light up only when they receive a certain signal from another cell. To test this type of communication in a 3-D structure, they printed a thin sheet of hydrogel filaments with “input,” or signal-producing bacteria and chemicals, overlaid with another layer of filaments of an “output,” or signal-receiving bacteria. They found the output filaments lit up only when they overlapped and received input signals from corresponding bacteria .

Yuk says in the future, researchers may use the team’s technique to print “living computers” — structures with multiple types of cells that communicate with each other, passing signals back and forth, much like transistors on a microchip.

“This is very future work, but we expect to be able to print living computational platforms that could be wearable,” Yuk says.

For more near-term applications, the researchers are aiming to fabricate customized sensors, in the form of flexible patches and stickers that could be engineered to detect a variety of chemical and molecular compounds. They also envision their technique may be used to manufacture drug capsules and surgical implants, containing cells engineered produce compounds such as glucose, to be released therapeutically over time.

“We can use bacterial cells like workers in a 3-D factory,” Liu says. “They can be engineered to produce drugs within a 3-D scaffold, and applications should not be confined to epidermal devices. As long as the fabrication method and approach are viable, applications such as implants and ingestibles should be possible.”

Here’s a link to and a citation for the paper,

3D Printing of Living Responsive Materials and Devices by Xinyue Liu, Hyunwoo Yuk, Shaoting Lin, German Alberto Parada, Tzu-Chieh Tang, Eléonore Tham, Cesar de la Fuente-Nunez, Timothy K. Lu, and Xuanhe Zhao. Advanced Materials DOI: 10.1002/adma.201704821 Version of Record online: 5 DEC 2017

© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

4D printing, what is that?

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According to an April 12, 2017 news item on ScienceDaily, shapeshifting in response to environmental stimuli is the fourth dimension (I have a link to a posting about 4D printing with another fourth dimension),

A team of researchers from Georgia Institute of Technology and two other institutions has developed a new 3-D printing method to create objects that can permanently transform into a range of different shapes in response to heat.

The team, which included researchers from the Singapore University of Technology and Design (SUTD) and Xi’an Jiaotong University in China, created the objects by printing layers of shape memory polymers with each layer designed to respond differently when exposed to heat.

“This new approach significantly simplifies and increases the potential of 4-D printing by incorporating the mechanical programming post-processing step directly into the 3-D printing process,” said Jerry Qi, a professor in the George W. Woodruff School of Mechanical Engineering at Georgia Tech. “This allows high-resolution 3-D printed components to be designed by computer simulation, 3-D printed, and then directly and rapidly transformed into new permanent configurations by simply heating.”

The research was reported April 12 [2017] in the journal Science Advances, a publication of the American Association for the Advancement of Science. The work is funded by the U.S. Air Force Office of Scientific Research, the U.S. National Science Foundation and the Singapore National Research Foundation through the SUTD DManD Centre.

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An April 12, 2017 Singapore University of Technology and Design (SUTD) press release on EurekAlert provides more detail,

4D printing is an emerging technology that allows a 3D-printed component to transform its structure by exposing it to heat, light, humidity, or other environmental stimuli. This technology extends the shape creation process beyond 3D printing, resulting in additional design flexibility that can lead to new types of products which can adjust its functionality in response to the environment, in a pre-programmed manner. However, 4D printing generally involves complex and time-consuming post-processing steps to mechanically programme the component. Furthermore, the materials are often limited to soft polymers, which limit their applicability in structural scenarios.

A group of researchers from the SUTD, Georgia Institute of Technology, Xi’an Jiaotong University and Zhejiang University has introduced an approach that significantly simplifies and increases the potential of 4D printing by incorporating the mechanical programming post-processing step directly into the 3D printing process. This allows high-resolution 3D-printed components to be designed by computer simulation, 3D printed, and then directly and rapidly transformed into new permanent configurations by using heat. This approach can help save printing time and materials used by up to 90%, while completely eliminating the time-consuming mechanical programming process from the design and manufacturing workflow.

“Our approach involves printing composite materials where at room temperature one material is soft but can be programmed to contain internal stress, and the other material is stiff,” said Dr. Zhen Ding of SUTD. “We use computational simulations to design composite components where the stiff material has a shape and size that prevents the release of the programmed internal stress from the soft material after 3D printing. Upon heating, the stiff material softens and allows the soft material to release its stress. This results in a change – often dramatic – in the product shape.” This new shape is fixed when the product is cooled, with good mechanical stiffness. The research demonstrated many interesting shape changing parts, including a lattice that can expand by almost 8 times when heated.

This new shape becomes permanent and the composite material will not return to its original 3D-printed shape, upon further heating or cooling. “This is because of the shape memory effect,” said Prof. H. Jerry Qi of Georgia Tech. “In the two-material composite design, the stiff material exhibits shape memory, which helps lock the transformed shape into a permanent one. Additionally, the printed structure also exhibits the shape memory effect, i.e. it can then be programmed into further arbitrary shapes that can always be recovered to its new permanent shape, but not its 3D-printed shape.”

Said SUTD’s Prof. Martin Dunn, “The key advance of this work, is a 4D printing method that is dramatically simplified and allows the creation of high-resolution complex 3D reprogrammable products; it promises to enable myriad applications across biomedical devices, 3D electronics, and consumer products. It even opens the door to a new paradigm in product design, where components are designed from the onset to inhabit multiple configurations during service.”

Here’s a video,


Uploaded on Apr 17, 2017

A research team led by the Singapore University of Technology and Design’s (SUTD) Associate Provost of Research, Professor Martin Dunn, has come up with a new and simplified 4D printing method that uses a 3D printer to rapidly create 3D objects, which can permanently transform into a range of different shapes in response to heat.

Here’s a link to and a citation for the paper,

Direct 4D printing via active composite materials by Zhen Ding, Chao Yuan, Xirui Peng, Tiejun Wang, H. Jerry Qi, and Martin L. Dunn. Science Advances  12 Apr 2017: Vol. 3, no. 4, e1602890 DOI: 10.1126/sciadv.1602890

This paper is open access.

Here is a link to a post about another 4th dimension, time,

4D printing: a hydrogel orchid (Jan. 28, 2016)

Mathematicians get illustrative

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Frank A. Farris, an associate Professor of Mathematics at Santa Clara University (US), writes about the latest in mathematicians and data visualization in an April 4, 2017 essay on The Conversation (Note: Links have been removed),

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Today, digital tools like 3-D printing, animation and virtual reality are more affordable than ever, allowing mathematicians to investigate and illustrate their work at the same time. Instead of drawing a complicated surface on a chalkboard, we can now hand students a physical model to feel or invite them to fly over it in virtual reality.

Last year, a workshop called “Illustrating Mathematics” at the Institute for Computational and Experimental Research in Mathematics (ICERM) brought together an eclectic group of mathematicians and digital art practitioners to celebrate what seems to be a golden age of mathematical visualization. Of course, visualization has been central to mathematics since Pythagoras, but this seems to be the first time it had a workshop of its own.

…

Visualization plays a growing role in mathematical research. According to John Sullivan at the Technical University of Berlin, mathematical thinking styles can be roughly categorized into three groups: “the philosopher,” who thinks purely in abstract concepts; “the analyst,” who thinks in formulas; and “the geometer,” who thinks in pictures.

Mathematical research is stimulated by collaboration between all three types of thinkers. Many practitioners believe teaching should be calibrated to connect with different thinking styles.

Borromean Rings, the logo of the International Mathematical Union. John Sullivan

Sullivan’s own work has benefited from images. He studies geometric knot theory, which involves finding “best” configurations. For example, consider his Borromean rings, which won the logo contest of the International Mathematical Union several years ago. The rings are linked together, but if one of them is cut, the others fall apart, which makes it a nice symbol of unity.

Apparently this new ability to think mathematics visually has influenced mathematicians in some unexpected ways,

Take mathematician Fabienne Serrière, who raised US$124,306 through Kickstarter in 2015 to buy an industrial knitting machine. Her dream was to make custom-knit scarves that demonstrate cellular automata, mathematical models of cells on a grid. To realize her algorithmic design instructions, Serrière hacked the code that controls the machine. She now works full-time on custom textiles from a Seattle studio.

In this sculpture by Edmund Harriss, the drill traces are programmed to go perpendicular to the growth rings of the tree. This makes the finished sculpture a depiction of a concept mathematicians know as ‘paths of steepest descent.’ Edmund Harriss, Author provided

Edmund Harriss of the University of Arkansas hacked an architectural drilling machine, which he now uses to make mathematical sculptures from wood. The control process involves some deep ideas from differential geometry. Since his ideas are basically about controlling a robot arm, they have wide application beyond art. According to his website, Harriss is “driven by a passion to communicate the beauty and utility of mathematical thinking.”

Mathematical algorithms power the products made by Nervous System, a studio in Massachusetts that was founded in 2007 by Jessica Rosenkrantz, a biologist and architect, and Jess Louis-Rosenberg, a mathematician. Many of their designs, for things like custom jewelry and lampshades, look like naturally occurring structures from biology or geology.

Farris’ essay is a fascinating look at mathematics and data visualization.

Free the nano—stop patenting publicly funded research

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Joshua Pearce, a professor at Michigan Technological University, has written a commentary on patents and nanotechnology for Nature magazine which claims the current patent regimes strangle rather than encourage innovation. From the free article,  Physics: Make nanotechnology research open-source by Joshua Pearce in Nature 491, 519–521 (22 November 2012) doi:10.1038/491519a (Note: I have removed footnotes),

Any innovator wishing to work on or sell products based on single-walled carbon nanotubes in the United States must wade through more than 1,600 US patents that mention them. He or she must obtain a fistful of licences just to use this tubular form of naturally occurring graphite rolled from a one-atom-thick sheet. This is because many patents lay broad claims: one nanotube example covers “a composition of matter comprising at least about 99% by weight of single-wall carbon molecules”. Tens of others make overlapping claims.

…

Patent thickets occur in other high-tech fields, but the consequences for nanotechnology are dire because of the potential power and immaturity of the field. Advances are being stifled at birth because downstream innovation almost always infringes some early broad patents. By contrast, computing, lasers and software grew up without overzealous patenting at the outset.

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Nanotechnology is big business. According to a 2011 report by technology consultants Cientifica, governments around the world have invested more than US$65 billion in nanotechnology in the past 11 years [my July 15, 2011 posting features an interview with Tim Harper, Cientfica CEO and founder, about the then newly released report]. The sector contributed more than $250 billion to the global economy in 2009 and is expected to reach $2.4 trillion a year by 2015, according to business analysts Lux Research. Since 2001, the United States has invested $18 billion in the National Nanotechnology Initiative; the 2013 US federal budget will add $1.8 billion more.

This investment is spurring intense patent filing by industry and academia. The number of nanotechnology patent applications to the US Patent and Trademark Office (USPTO) is rising each year and is projected to exceed 4,000 in 2012. Anyone who discovers a new and useful process, machine, manufacture or composition of matter, or any new and useful improvement thereof, may obtain a patent that prevents others from using that development unless they have the patent owner’s permission.

Pearce makes some convincing points (Note: I have removed a footnote),

Examples of patents that cover basic components include one owned by the multinational chip manufacturer Intel, which covers a method for making almost any nanostructure with a diameter less than 50 nm; another, held by nanotechnology company NanoSys of Palo Alto, California, covers composites consisting of a matrix and any form of nanostructure. And Rice University in Houston, Texas, has a patent covering “composition of matter comprising at least about 99% by weight of fullerene nanotubes”.

The vast majority of publicly announced IP licence agreements are now exclusive, meaning that only a single person or entity may use the technology or any other technology dependent on it. This cripples competition and technological development, because all other would-be innovators are shut out of the market. Exclusive licence agreements for building-block patents can restrict entire swathes of future innovation.

Pearce’s argument for open source,

This IP rush assumes that a financial incentive is necessary to innovate, and that without the market exclusivity (monopoly) offered by a patent, development of commercially viable products will be hampered. But there is another way, as decades of innovation for free and open-source software show. Large Internet-based companies such as Google and Facebook use this type of software. Others, such as Red Hat, make more than $1 billion a year from selling services for products that they give away for free, like Red Hat’s version of the computer operating system Linux.

An open-source model would leave nanotechnology companies free to use the best tools, materials and devices available. Costs would be cut because most licence fees would no longer be necessary. Without the shelter of an IP monopoly, innovation would be a necessity for a company to survive. Openness reduces the barrier for small, nimble entities entering the market.

John Timmer in his Nov. 23, 2012 article for Wired.co.uk expresses both support and criticism,

Some of Pearce’s solutions are perfectly reasonable. He argues that the National Science Foundation adopt the NIH model of making all research it funds open access after a one-year time limit. But he also calls for an end of patents derived from any publicly funded research: “Congress should alter the Bayh-Dole Act to exclude private IP lockdown of publicly funded innovations.” There are certainly some indications that Bayh-Dole hasn’t fostered as much innovation as it might (Pearce notes that his own institution brings in 100 times more money as grants than it does from licensing patents derived from past grants), but what he’s calling for is not so much a reform of Bayh-Dole as its elimination.

Pearce wants changes in patenting to extend well beyond the academic world, too. He argues that the USPTO should put a moratorium on patents for “nanotechnology-related fundamental science, materials, and concepts.” As we described above, the difference between a process innovation and the fundamental properties resulting in nanomaterial is a very difficult thing to define. The USPTO has struggled to manage far simpler distinctions; it’s unrealistic to expect it to manage a moratorium effectively.

While Pearce points to the 3-D printing sector admiringly, there are some issues even there, as per Mike Masnick’s Nov.  21, 2012 posting on Techdirt.com (Note:  I have removed links),

We’ve been pointing out for a while that one of the reasons why advancements in 3D printing have been relatively slow is because of patents holding back the market. However, a bunch of key patents have started expiring, leading to new opportunities. One, in particular, that has received a fair bit of attention was the Formlabs 3D printer, which raised nearly $3 million on Kickstarter earlier this year. It got a ton of well-deserved attention for being one of the first “low end” (sub ~$3,000) 3D printers with very impressive quality levels.

Part of the reason the company said it could offer such a high quality printer at a such a low price, relative to competitors, was because some of the key patents had expired, allowing it to build key components without having to pay astronomical licensing fees. A company called 3D Systems, however, claims that Formlabs missed one patent. It holds US Patent 5,597,520 on a “Simultaneous multiple layer curing in stereolithography.” While I find it ridiculous that 3D Systems is going legal, rather than competing in the marketplace, it’s entirely possible that the patent is valid. It just highlights how the system holds back competition that drives important innovation, though.

3D Systems claims that Formlabs “took deliberate acts to avoid learning” about 3D Systems’ live patents. The lawsuit claims that Formlabs looked only for expired patents — which seems like a very odd claim. Why would they only seek expired patents? …

I strongly suggest reading both Pearce’s and Timmer’s articles as they both provide some very interesting perspectives about nanotechnology IP (intellectual property) open access issues. I also recommend Mike Masnick’s piece for exposure to a rather odd but unfortunately not uncommon legal suit designed to limit competition in a relatively new technology (3-D printers).