Physicists from the University of Amsterdam have developed a method to print three-dimensional structures in ice. Last December,

Apple (release notes, security, enterprise, developer, full installer, IPSW):

Explore what’s new for macOS 27.

The page is designed in an annoying way that requires sideways scrolling, and there doesn’t seem to be a PDF list of the new features like in previous years.

See also:

• Jason Snell
• Juli Clover
• Marcus Mendes
• William Gallagher
• Mr. Macintosh
• Reddit

Jeff Johnson:

There’s also a DEPRECATION NOTICE at the top of the man page that lists the diskutil replacements for hdiutil subcommands.

Patrick Wardle:

Fixed: launchd no longer supports loading launchd property list files with the quarantine extended attribute.

Dave Nanian:

[Even] though a bootable backup is properly configured to boot, they aren’t showing up as choices in either the startup disk preference pane or the startup picker. (FB24210103, reported quite a while ago, Apple friends.)

Previously:

• Golden Gate Release Candidate
• Preparing to Update to Golden Gate
• macOS 27 Public Beta
• Glow Leopard
• macOS 27 Golden Gate Announced
• macOS Tahoe 26

Update (2026-09-17): See also: Hacker News.

Andrew Cunningham (Hacker News):

Generative AI is unavoidable if you install macOS 27 Golden Gate. I’m being very literal: There used to be a toggle you could hit if you wanted to turn off Apple Intelligence and delete the gigabytes’ worth of AI models it would download to your disk, and now there isn’t. Apple Intelligence defines the Golden Gate release, in everything from its marketing to its features to the chips it runs on to the amount of space it takes on your disk.

[…]

More impressively, for apps that support it, the iPhone Mirroring window can now be resized dynamically while running apps. Apps will resize themselves to take up all the available space, and once the window is wide enough, you can even take advantage of multi-column iPad-style views for the apps that offer them.

[…]

For most Mac users, though, Golden Gate is a no-brainer update with few major downsides. It won’t hurt anything to wait until the 27.1 or 27.2 release if you’re already on macOS 15 Sequoia or macOS 26 Tahoe and you’re not in a hurry.

Juli Clover:

macOS Golden Gate: 10 Features to Try First

Paul Haddad:

Did Virtualization under 27 get hit with the slow stick? Trying to run a Mac VM on my M1 Ultra and it feels basically unusable. Getting Intel flashbacks.

Jeff Johnson:

In System Settings Privacy & Security, the Accessibility pane has been renamed to Device Control and Data Access.

Avi Drissman:

Have you been noticing that, starting with macOS 27, you have been consistently failing to SSH to a remote machine? Is it the case that the remote machine’s password ends with a shifted character?

There is a new setting: “Shift Return sends Meta Return” under Settings > Profiles > (profile) > Keyboard. This setting (enabled by default!) will cause a shift-return keypress to insert an ESC before the return is sent.

Rich Trouton:

As part of testing macOS Golden Gate, it was discovered by myself and others that MDM enrollment does not appear to completely work.

Adam Maxwell (tweet):

Golden Gate broke AuthorizationExecuteWithPrivileges such that spawned tasks no longer inherit PATH of the calling process[…]

Daniel Compton:

After upgrading to macOS 27 Golden Gate, my beloved copy of 1Password 7 started crashing every time I unlocked it.

[…]

If you’re planning ahead, you can disable Watchtower from Settings before you upgrade to macOS 27, but if you’ve already upgraded, then you’ll need to disable it with the following terminal command[…]

Update (2026-09-21): Benjamin Mayo:

Ever since updating to Golden Gate, my Mac now periodically makes a scratchy paper alert sound. No idea from what.

Chris Pepper:

Hopefully 1Password will upgrade v7 for OS 27 compatibility, but I can’t count on them fixing bugs in v7 — they’re pushing users to v8.

I found a ‘fix’ for this crash, but that command didn’t work (even after enabling Full Disk Access for Terminal so it could actually execute), and isn’t available on iPhone or iPad.

Nicholas Riley:

Golden Gate status: wow, the new menu extra/Control Center area is rough. Not just unpolished UI behaviors but multiple crashes. Hidden Bar is no longer functional and none of the replacements I found actually worked, while having about 100 features I don’t want.

System keyboard shortcuts also seem to be an area that weren’t well tested. My preferred screenshot shortcuts were ignored until I opened that section of System Settings, and some Siri thing created a conflict with Spotlight so I get both of them when I press ⇧⌘Space.

Previously:

• Golden Gate Liquid Glass

Update (2026-09-23): Jesse Squires:

macOS golden gate is still shockingly terrible in unexpected ways.

Steve Troughton-Smith:

I’m no math expert, but I’m pretty sure this doesn’t add up to anywhere near 16GB. I’ve only started seeing this dialog in the release build of macOS 27.0, despite running the betas all summer, so clearly there are some ghosts in this build

Mario Guzmán:

Okay… how do you

1. make everything super huge like the text and pictures… while
2. having way more empty space than you need AND STILL have to
3. truncate your text labels?

8 of the 9 text labels are truncated.

Can we please have designers who know how to design for DESKTOP software and NOT magazines/print?

Jeff Johnson:

There are a surprising number of behavioral bugs in Golden Gate. It's not just a superficial update. Apple is basically breaking AppKit.

Mark Lilback:

I reported a bug to Apple in May, found while building Alcove. Two OS releases later it still isn’t fixed. It has gotten worse with each one.

[…]

On the betas the whole window went blank after the Cmd-Tab: sidebar, content, detail pane, status bar, everything but the toolbar. On the 27.0 release it usually doesn’t wait for the Cmd-Tab. In 5 of 6 clean launches the window came up with only the toolbar drawn. Cmd-Tabbing away and back doesn’t fix it. It moves the sidebar’s first row up under the traffic-light buttons and leaves the rest of the window empty[…]

Jeff Johnson (Reddit):

Golden Gate Finder bug:

If you start dragging a file, the mouse scroll wheel stops working.

Jeff Johnson:

I’m seeing a bug on Golden Gate where main menu item titles are not displayed if the item is added to the menu after launch. Examples: the Safari Develop menu and the Profile menus of Chrome and Firefox.

Update (2026-09-24): Avi Drissman:

It’s bizarre that hiding a main menu item would hold the space rather then shift things over.

Jeff Johnson:

Search on Golden Gate is twice as good.

Update (2026-09-25): Ric Ford:

Randy Singer emailed us about printer and scanner failures following macOS 27 installation. Fortunately, there’s a fix: reinstalling Apple’s deprecated and removed Rosetta 2 emulation code[…]

Paul Kafasis:

We’re also already recommending upgrading your Mac to Golden Gate. The new OS includes several important audio improvements, and as a result, Golden Gate provides the best experience when using our apps. Below, you’ll find details on key bug fixes Apple included in MacOS 27.

pdfu (via Jeff Johnson):

Hidden behind a feature flag, the System Settings app can now be resized in any direction. You can make the app window narrower than the default too, or adjust the sidebar to get even more space.

Update (2026-09-28): Matt:

Steve Jobs would fire the entire company and replace them with AI if he was alive to see this

Collin Allen:

Turns out, Backblaze is half busted on macOS 27 and there’s no fix yet. Have to launch /Library/Backblaze.bzpkg/bzbmenu.app manually for now, it seems.

Update (2026-10-05): Karsten Kusche:

Kudos to 1Password for providing an update for version 7 on iOS and macOS to restore compatibility with this year’s operating systems!!

A journal committed to scientific materialism publishes an article explicitly challenging evolution and promoting design.

Source

In 2007, a piece of space debris punched a bullet-like hole through the radiator panel of the US space shuttle Endeavor. The shuttle program ended in 2011, but the space debris problem has only intensified as we launch more and more satellite constellations, telescopes, and spacecraft into orbit. That's why Chinese scientists have devised a new aluminum material inspired by eggshells that they believe could offer enhanced protection against debris fragments, according to a new paper published in the Journal of Applied Physics.

Eggshells have long fascinated scientists because of their mechanical properties. For instance, it's well known that cracking an egg requires applying just enough force to the center to achieve a clean break without completely shattering the shell. In 2012, MIT mechanical engineer Pedro Reis co-authored a paper demonstrating the link between an egg's ovoid geometry and its rigidity, a major factor when predicting how much force an object can endure before cracking. (As I wrote for Slate at the time, rigidity is related to, but distinct from, strength. If one eggshell has tiny cracks and the other doesn't, both shells have different strengths—the cracked one will break more easily—but the same rigidity.)

Reis started studying eggshells after participating in a popular physics demonstration: walking on cartons of eggs without breaking them. The key, he learned, was to align the eggs with their narrow tip (the most crack-resistant part) pointing up, and then carefully place one's feet to distribute one's weight over the entire surface area. This ensures that no single egg is overloaded. While it takes around 5.5 pounds of force to crack an egg, that depends on the direction in which the force is applied, as well as its distribution over the shell's surface.

Read full article

Comments

© Wang et al., 2026

In 2007, a piece of space debris punched a bullet-like hole through the radiator panel of the US space shuttle Endeavor. The shuttle program ended in 2011, but the space debris problem has only intensified as we launch more and more satellite constellations, telescopes, and spacecraft into orbit. That's why Chinese scientists have devised a new aluminum material inspired by eggshells that they believe could offer enhanced protection against debris fragments, according to a new paper published in the Journal of Applied Physics.

Eggshells have long fascinated scientists because of their mechanical properties. For instance, it's well known that cracking an egg requires applying just enough force to the center to achieve a clean break without completely shattering the shell. In 2012, MIT mechanical engineer Pedro Reis co-authored a paper demonstrating the link between an egg's ovoid geometry and its rigidity, a major factor when predicting how much force an object can endure before cracking. (As I wrote for Slate at the time, rigidity is related to, but distinct from, strength. If one eggshell has tiny cracks and the other doesn't, both shells have different strengths—the cracked one will break more easily—but the same rigidity.)

Reis started studying eggshells after participating in a popular physics demonstration: walking on cartons of eggs without breaking them. The key, he learned, was to align the eggs with their narrow tip (the most crack-resistant part) pointing up, and then carefully place one's feet to distribute one's weight over the entire surface area. This ensures that no single egg is overloaded. While it takes around 5.5 pounds of force to crack an egg, that depends on the direction in which the force is applied, as well as its distribution over the shell's surface.

Read full article

Comments

© Wang et al., 2026

In 2007, a piece of space debris punched a bullet-like hole through the radiator panel of the US space shuttle Endeavor. The shuttle program ended in 2011, but the space debris problem has only intensified as we launch more and more satellite constellations, telescopes, and spacecraft into orbit. That's why Chinese scientists have devised a new aluminum material inspired by eggshells that they believe could offer enhanced protection against debris fragments, according to a new paper published in the Journal of Applied Physics.

Eggshells have long fascinated scientists because of their mechanical properties. For instance, it's well known that cracking an egg requires applying just enough force to the center to achieve a clean break without completely shattering the shell. In 2012, MIT mechanical engineer Pedro Reis co-authored a paper demonstrating the link between an egg's ovoid geometry and its rigidity, a major factor when predicting how much force an object can endure before cracking. (As I wrote for Slate at the time, rigidity is related to, but distinct from, strength. If one eggshell has tiny cracks and the other doesn't, both shells have different strengths—the cracked one will break more easily—but the same rigidity.)

Reis started studying eggshells after participating in a popular physics demonstration: walking on cartons of eggs without breaking them. The key, he learned, was to align the eggs with their narrow tip (the most crack-resistant part) pointing up, and then carefully place one's feet to distribute one's weight over the entire surface area. This ensures that no single egg is overloaded. While it takes around 5.5 pounds of force to crack an egg, that depends on the direction in which the force is applied, as well as its distribution over the shell's surface.

Read full article

Comments

© Wang et al., 2026

Chinese retailer AliExpress has been caught fingerprinting visitors after one of the metrics—an outdated technique that measures inaudible sounds it sends to browsers—impeded a researcher's ability to use his bluetooth headphones.

Researcher Matthew Callaghan said he stumbled on the stealthy tracking by mistake. After loading the AliExpress homepage, audio from his phone stopped playing over his multipoint headphones, which accept connections from more than one device at a time. He set the headphones to play sounds from his phone except when his PC was producing audio. Each time he loaded AliExpress, the phone audio stopped. Each time he closed the tab the site was loaded into, the phone was once again audible.

Users can't hear it, but browsers can

While investigating the odd behavior, Callaghan said he found two highly obfuscated scripts. Together, they rendered a graph that analyzed the WebAudio readings of each visiting browser. This graph acted as an oscillator that measured Sawtooth waves, which are common in output from digital audio.

Read full article

Comments

© Getty Images

Using the same basic physics based on the familiar hollow tone produced by blowing across an empty bottle, researchers in Switzerland have developed a sound-powered propulsion system that can steer microrobots and even lift tiny machines.

In a new study published in Science Advances, engineers at the Swiss Federal Institute of Technology Lausanne (EPFL) demonstrated that 3D-printed cavities known as Helmholtz resonators can convert sound into directed jets of air and usable thrust.

The researchers built devices ranging from centimeters down to micrometers, used sound to propel and steer tiny boats, and created two microscopic flying machines—one microrobot lifted directly by acoustic thrust and another using rapidly spinning rotor blades. One version generated nearly five times its own weight in thrust, while another spun at up to 13,000 revolutions per minute to produce aerodynamic thrust.

The work points to a new way to power small robots without conventional motors, while also exposing the considerable engineering problems that remain before such machines can operate autonomously.

“While acoustic resonators have been extensively studied in liquids for the realization of untethered microrobots, their implementation in air remains largely unexplored,” researchers write. “The actuation scheme is compatible with even further miniaturization, pushing the boundaries of robotics and aeronautics.”

The idea behind the technology is surprisingly familiar. Blow across the top of an empty bottle and you hear a deep, hollow note created as the air trapped inside begins to vibrate.

Known as Helmholtz resonance, the effect happens because the air inside the bottle and its narrow opening behave somewhat like a mass attached to a spring. When sound at the right frequency excites a specially designed resonator, those vibrations become much stronger, forcing air rapidly through the opening. The resulting airflow can form a directional jet powerful enough to generate thrust.

The researchers set out to harness the same physics behind Helmholtz resonance as an unconventional propulsion method for microrobots.

The researchers designed tiny cavities that take advantage of the same principle. When sound hits one of these resonators at just the right frequency, the air in its narrow neck begins moving rapidly back and forth.

Because that airflow is slightly uneven as it enters and exits, it creates a small but focused jet of air. That jet produces thrust, giving the resonator enough force to help move or even lift a microrobot.

The team 3D-printed resonators ranging from centimeter to micrometer scales, designing them to respond to frequencies between roughly 200 hertz and 40 kilohertz. Experiments showed that larger cavities generally produced greater thrust, while the geometry and thickness of the resonator’s neck played a particularly important role in determining performance.

Importantly, researchers could tune different resonators to different frequencies. That means sound does more than supply power; frequency can effectively serve as a control signal.

The researchers demonstrated the concept using miniature boats equipped with acoustic resonators. One early prototype carried a resonator tuned to 1.2 kilohertz and moved only when exposed to sound at that frequency.

More advanced versions used separate resonators for propulsion and steering, allowing the researchers to guide a boat around obstacles remotely and along a figure-eight course with a mean tracking error of just 5.70 millimeters.

The team also showed that an external speaker is not always necessary. By attaching small vibration transducers directly to resonators, they could send sound through the robot’s structure itself.

This approach allowed the researchers to build a fully integrated boat equipped with its own battery, control electronics, and acoustic transducers. Bluetooth commands activated resonators tuned for propulsion and steering, with a total communication latency of about 30 milliseconds. The boat successfully traced the letters “EPFL,” navigated past obstacles, and could be steered back on course after researchers deliberately disturbed it by blowing air or physically pushing it.

However, shrinking the technology into flying microrobots provided the study’s most striking demonstration.

One microflier consisted of three microscopic resonators operating at 40 kilohertz and weighed only about 150 micrograms. Focused ultrasound caused each resonator to eject a tiny jet of air downward. Together, the three produced a thrust-to-weight ratio of approximately 4.9. The machine accelerated upward, climbed roughly 12 millimeters before settling around seven millimeters above its starting position.

A second design took a different approach. Instead of pointing the acoustic jets downward, the researchers used them to spin a rotor fitted with tiny aerodynamic blades. The entire aircraft weighed 184 micrograms.

Once exposed to ultrasound, the rotor accelerated to approximately 13,000 rpm. Its blades generated enough aerodynamic thrust for takeoff before settling to roughly 6,500 rpm while hovering.

Turning the device upside down prevented it from ascending, helping confirm that aerodynamic thrust, rather than acoustic radiation pressure alone, enabled flight.

Researchers demonstrated unconstrained flight with both microrobot designs. The direct-thrust version climbed rapidly but sometimes flipped in the air. The spinning version was more stable, apparently because its swift rotation provided a gyroscopic stabilizing effect similar to that found in helicopters and spinning discs.

Ultimately, the experiments remain proof-of-concept demonstrations rather than prototypes of free-ranging autonomous microrobots. Airborne propulsion requires external acoustic hardware capable of keeping a sufficiently strong sound field focused on a tiny moving object. That essentially limits the robot’s operating area. Putting the acoustic source onboard offers greater autonomy but might significantly increase the robot’s weight.

The current flying system also operates at a single 40-kilohertz frequency, restricting how independently its resonators can be controlled. The researchers suggest future multifrequency ultrasonic arrays could selectively activate different resonators, allowing small aircraft to steer and coordinate their movement through sound alone.

Further miniaturization is technically possible. Modern 3D nanoprinting can fabricate structures with resolutions around 700 nanometers, possibly allowing resonators only several micrometers across. However, at those scales, viscous forces become increasingly important and may dramatically reduce thrust, meaning simply shrinking the existing design may eventually stop working.

Still, the wider concept could go beyond flying machines. Researchers envision flexible structures containing many differently tuned resonators that can bend, vibrate, or change shape depending on the applied sound frequency, possibly resulting in shape-morphing microrobots and mechanical metamaterials.

“Our work extends the concept of acoustic manipulation toward active propulsion by harnessing cavity resonance to generate directional thrust and controlled motion,” the researchers write. “This approach broadens the scope of airborne acoustic actuation toward small-scale robots capable of autonomous operation in open environments.”

The recent study, “Acoustic Resonators as Wireless Actuators in Air for Small-Scale Robots,” was published in Science Advances. 

Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan.  Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com 

Glass bottles tossed in the trash are finding new life thanks to a collaboration between the Department of

A quiet shift in silicon manufacturing could be taking shape inside a new study on porous reaction-bonded silicon nitride, a ceramic material valued for its strength, thermal stability and resistance to chemical attack. Researchers T.G. Aguirre, E. Cakmak, M.D. Richardson and colleagues are investigating how the size of additively manufactured silicon components affects their conversion into silicon nitride through a pressureless nitriding process. Published in npj Advanced Manufacturing, the work connects binder jet 3D printing with a manufacturing route that could make complex ceramic structures easier to produce.

The central idea is deceptively simple: print a component from silicon powder, then expose it to nitrogen so that the silicon reacts and forms silicon nitride. In practice, however, the transformation is governed by a network of interacting physical and chemical processes. Nitrogen must penetrate the part, reach reactive silicon surfaces and diffuse through newly formed ceramic layers. Heat must also move through the structure, while gases generated or trapped during processing must escape. As component dimensions change, these processes can behave very differently.

Binder jet additive manufacturing offers a distinctive route for creating such parts. Instead of melting powder with a laser or electron beam, the process selectively deposits a liquid binder to join powder particles layer by layer. The resulting “green” component is then typically dried and thermally treated to remove the binder, leaving a fragile, porous body. For silicon-based structures, that interconnected porosity can become a processing advantage, allowing nitrogen to travel through the material during the subsequent reaction.

The researchers’ focus on size effects addresses a major challenge in scaling ceramic additive manufacturing from laboratory specimens to useful components. A thin printed sample may nitridize relatively quickly because nitrogen has only a short distance to travel. A thicker or larger part presents a far more demanding environment. Its interior can receive nitrogen more slowly, and the reaction front may progress unevenly from the outer surface inward. Differences in heating rate, temperature distribution and gas transport can produce variations in conversion, density and final microstructure.

The term “pressureless nitriding” is crucial to the study’s technological appeal. Many advanced ceramic manufacturing methods depend on external pressure, specialized furnaces or high-energy consolidation steps to achieve the desired structure. A pressureless route instead relies on controlled heating and the chemical affinity between silicon and nitrogen. If the reaction can be managed uniformly, manufacturers could potentially create intricate silicon nitride components without applying mechanical pressure during conversion, simplifying equipment requirements and expanding the range of printable geometries.

Silicon nitride is an especially attractive target because it combines several properties that are difficult to obtain in a single engineering material. It can withstand high temperatures, resist wear and corrosion, and maintain useful mechanical performance under demanding conditions. Those characteristics have made silicon nitride relevant to applications ranging from bearings and cutting tools to heat-resistant components and advanced energy systems. A porous version offers additional possibilities, including lightweight structures, filtration, thermal management and engineered surfaces where controlled pathways through the material are valuable.

The study’s attention to porosity is equally important. In reaction-bonded ceramics, pores are not merely defects; they can serve as channels for reactant transport. At the same time, excessive or poorly distributed porosity can weaken the final component and interfere with complete conversion. The scientific challenge is therefore to balance openness and strength. The printed silicon body must remain permeable enough for nitrogen to reach its interior, while the reaction must generate a coherent silicon nitride framework rather than leaving unreacted silicon or creating damaging gradients.

By examining components of different sizes, the researchers are addressing a question with direct implications for industrial design: can processing rules developed for small printed samples be applied to larger parts? The answer depends on how reaction kinetics, diffusion and heat transfer scale with geometry. A process that appears reliable in a small coupon may produce a different result in a thick wall, enclosed channel or complex lattice. Understanding those differences can help engineers determine allowable dimensions, optimize furnace schedules and design structures around the chemistry of nitridation rather than treating manufacturing as a purely geometric exercise.

The broader significance of the work lies in the convergence of three fields: powder-based additive manufacturing, reaction-bonded ceramics and transport-driven materials processing. Instead of printing a finished ceramic directly, the approach uses additive manufacturing to create a carefully engineered precursor and then transforms it chemically. That strategy could unlock shapes that are difficult to machine from dense silicon nitride, while reducing the need for conventional molds and tooling. As manufacturers seek lighter, more complex and more resource-efficient components, controlling size-dependent reactions may become as important as improving printer resolution.

The research arrives at a moment when additive manufacturing is moving beyond demonstrations of intricate shapes toward repeatable production of functional materials. Its emphasis on pressureless nitriding of binder jet additively manufactured silicon highlights a practical bottleneck often hidden behind spectacular 3D-printing images: the printed object is only the beginning. The final performance depends on what happens during post-processing, when gases, heat and chemical reactions determine the internal structure. By clarifying how component size influences that transformation, Aguirre, Cakmak, Richardson and their collaborators are helping map a route from powder and binder to porous silicon nitride parts designed for the high-temperature technologies of the future.

Subject of Research: Porous reaction-bonded silicon nitride produced through pressureless nitriding of binder jet additively manufactured silicon, with a focus on size effects.

Article Title: Porous reaction-bonded silicon nitride: Size effects for pressureless nitriding of binder jet additively manufactured silicon

Article References: Aguirre, T.G., Cakmak, E., Richardson, M.D. et al. “Porous reaction-bonded silicon nitride: Size effects for pressureless nitriding of binder jet additively manufactured silicon.” npj Advanced Manufacturing (2026). https://doi.org/10.1038/s44334-026-00110-y

Image Credits: AI Generated

DOI: 10.1038/s44334-026-00110-y

Keywords: Silicon nitride, reaction-bonded ceramics, pressureless nitriding, binder jet additive manufacturing, silicon, porous materials, size effects.

Researchers at the U.S. Department of Energy’s (DOE) Oak Ridge National Laboratory (ORNL) have created a new tool

Researchers have demonstrated an unusual new form of 3D printing capable of building entirely new structures directly onto—and even around—existing objects in just seconds. In a series of experiments, the technique printed microscopic fluid channels around embedded glass spheres, fabricated precision gears onto polished steel rods, and even built a miniature lens directly onto the surface of a working LED.

The breakthrough, described in a paper published in Nature Communications, relies on an advanced form of tomographic volumetric additive manufacturing (TVAM) that allows researchers to “overprint” new structures onto components made from a wide range of materials, including metal, glass, and preassembled microfluidic components. Instead of constructing objects layer by layer like conventional 3D printers, the system projects precisely calculated light patterns into a rotating vat of photosensitive resin, causing an entire three-dimensional object to solidify almost simultaneously within seconds.

The advancement could represent a major step toward making volumetric 3D printing practical in real-world manufacturing environments, where new components often must be integrated with parts that already exist.

It additionally highlights the growing sophistication of computational techniques that can accurately model how light behaves as it passes through materials that absorb, scatter, refract, or reflect light.

“Tomographic Volumetric Additive Manufacturing (TVAM) is a light-based 3D printing technique capable of producing centimeter-scale objects within seconds,” researchers write. “This work demonstrates a broad range of overprinting scenarios, where new structures are directly printed onto or around pre-existing components made from different materials.”

Unlike conventional stereolithography or fused-filament printers that gradually build an object from one direction, tomographic volumetric printing projects hundreds of two-dimensional light patterns into a rotating container filled with liquid resin.

As the resin accumulates enough light energy, the desired three-dimensional structure appears almost simultaneously throughout the volume rather than emerging layer by layer. The approach can produce centimeter-scale objects in mere seconds.

However, until now, one of the technology’s greatest challenges has been accurately calculating how light travels through complicated environments.

Existing objects inside the resin can block, scatter, or bend incoming light, degrading print quality. Conventional models often assume these objects are either completely transparent or completely opaque. This is an oversimplification that breaks down in realistic manufacturing scenarios.

To overcome those limitations, the team developed an upgraded computational framework called Dr.TVAM. Built upon physically based ray tracing, the software models how light propagates through materials with different optical properties while simultaneously optimizing the projected light patterns needed to create the desired object.

Because the framework accounts for reflection, refraction, scattering, absorption, and arbitrary container shapes, it can successfully print structures around components that previously would have interfered with the process.

One of the study’s most compelling demonstrations involved manufacturing microfluidic channels directly inside sealed, preassembled square chambers. Microfluidic devices contain microscopic channels that transport tiny volumes of liquids and are widely used in biomedical research, diagnostics, and organ-on-a-chip systems.

Instead of fabricating the channels separately and assembling the device afterward—a process that can introduce contamination or leaks—the researchers successfully printed perfusable channels directly inside an already assembled chamber while accounting for inlet and outlet structures that would otherwise obstruct the light.

They demonstrated straight channels, branching networks, and spiral geometries capable of carrying fluid after fabrication. Supplementary demonstrations showed colored dye successfully flowing through the finished structures.

The researchers then pushed the concept even further by creating what they describe as context-aware printing. In this experiment, they embedded two tiny glass spheres inside a hydrogel-filled chamber, rapidly determined each sphere’s three-dimensional position using two camera images, and generated customized print patterns in less than a minute.

Those optimized projections produced hollow channels connecting each sphere to inlet and outlet ports while simultaneously printing protective cavities around the spheres themselves. The complete workflow—from detecting the embedded objects to generating printing instructions and fabricating the final structure—required less than three minutes.

That ability could eventually enable highly customized biomedical manufacturing, where printers automatically adapt to the precise location of living tissues, organoids, or other biological materials rather than requiring perfect positioning beforehand.

Another experiment highlighted why precisely modeling light matters.

Previous demonstrations of volumetric overprinting treated metal components as though they completely absorbed incoming light. In reality, polished metal reflects and scatters significant amounts of light, creating distortions that reduce print quality.

Researchers tested both assumptions by printing a gear directly onto a polished steel rod. When the software ignored scattered light, the gear’s fine holes became over-polymerized and poorly defined.

After including realistic scattering behavior into the optical model, however, the resulting gear preserved those elaborate features far more accurately, increasing simulated print fidelity substantially. The improvement was confirmed experimentally.

Researchers even went as far as demonstrating that the process could print directly onto an electronic component.

Using an LED-based volumetric printing system, the researchers fabricated both a miniature lens and a small cross-shaped symbol directly onto the surface of a red LED. When illuminated, the printed lens projected the symbol onto a screen, successfully transforming the LED into a tiny optical projector without requiring additional assembly. The experiment showcased how optical elements themselves could potentially be integrated directly onto existing electronic hardware during manufacturing.

Beyond the individual demonstrations, the work additionally underscores an important trend in additive manufacturing: increasingly sophisticated software is becoming just as important as advances in hardware.

Instead of relying on simplified mathematical approximations, the new framework performs physically based optical simulations capable of modeling arbitrary geometries along with material properties.

The software has been released as open source, along with configuration files and experimental data, allowing other researchers to reproduce and expand upon the 3D printing work.

Although the current demonstrations remain laboratory-scale, the possible implications could extend well beyond experimental 3D printing. Biomedical researchers could eventually fabricate sterile microfluidic systems without multi-step assembly. Optical engineers may integrate lenses directly onto light sources. Manufacturers could add custom features to finished components without redesigning entire production processes.

Researchers also note that future improvements could further increase realism through incorporating additional physical effects, including changes in refractive index during polymerization and the diffusion of chemical inhibitors during printing. Those refinements could expand the technology’s accuracy and enable even more complex manufacturing scenarios.

“In summary, Dr.TVAM, our computational framework, has shown to be capable of modeling different optical situations for TVAM,” researchers write. “We believe this significantly expands the application space for TVAM, enabling the creation of complex, functionalized, and multi-component devices from applications in mechanics, optics, or biofabrication.”

Study: Wechsler F, et al. “Overprinting with tomographic volumetric additive manufacturing.” Nature Communications (2026).

Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan.  Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com