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Matter of Tech Lab

Cornell Tech, NYC

We envision a future in which digital fabrication provides real value to end-uses. Machines have gotten more capable and affordable leading to broad adoption by enthusiasts. We have seen this pattern in with digital computing itself; computer clubs in the 80s allowed enthusiasts to build cool tech demos, but these remained largely irrelevant to the broader society. We believe we will not bridge the gap to the other 99% of people by making better tools for makers.

In the Matter of Tech Lab, we investigate how to increase the quality and complexity of models by allowing users to build on the work of others. This will allow non-experts to create meaningful and useful models (in contrast to what is commonly fabricated by enthusiasts). We build tools to increase portability of models, and facilitate remixing at different levels of granularity. We build environments to troubleshoot hardware, allowing users with less skill to build more advanced projects. And finally, we develop form factors for fabrication machines to gradually integrate in the lives of the other 99% of people. We publish our work at top-tier HCI conferences ACM CHI, ACM UIST, and ACM SCF.

If you want to work with us: jump right here



Thijs Roumen

Assistant Professor


Ofer Berman

(PhD with Ezri Tarazi at Technion)


Amrit Kwatra

PhD Student


Tobias Weinberg

PhD student


Shuo Feng

PhD student


Zekun Chang

PhD student


Ilan Mandel

PhD Student


Bo Liu

PhD student


Ricky Gonzalez

PhD Student


Ritik Batra

PhD student


Cindy Yang

Master Student
(Harvard Design Technology)


William J. Reid

Master Student (Health Tech)


Yixuan Wang

Master Student (Urban Tech)

image coming

Leonardo Bueno

Master Student (Computer Science)


Han Jun Kim

Master Student
(Architecture, Art, and Planning)


Lewis Fitzgerald Campbell

Master Student
(Fiber Science and Apparel Design)


Henry Sanchez

Master Student
(Fiber Science and Apparel Design)


Maia Hirsch

Research Intern
(ME undergrad at Technion)


Dec 7th, 2023

Shuo Feng receives the 2024 XR prototyping grant from the XR Collaboratory, congrats!

Nov 14th, 2023

Ofer Berman joins the Matter of Techlab as post-doc coming in from Technion, Israel! Welcome to the team!

Nov 7th, 2023

Master students William J. Reid Hernandez, Leonardo David Bueno, and Yixuan Wang will join us next semester for independent research studies! Welcome to the team!

Nov 1st, 2023

Thijs Roumen will serve as Subcommittee chair for DIS 2023

Oct 8-10, 2023

Matter of Techlab hosts the 2023 ACM Symposium on Computational Fabrication with Thijs Roumen serving as General Chair, Amrit Kwatra serving as Demo Chair, and other lab members as SVs!

Oct 8, 2023

Thijs Roumen finishes Chicago marathon in 2:51:22

Sept 15, 2023

Thijs Roumen granted 7k travel grant for collaboration with Ezri Tarazi from Technion.

Aug 14, 2023

Cindy joins as virtual lab member! And Albina Krasykova and Fahad Tahir wrap up their summer internships! Thanks for a great time!

Jul 1, 2023

Thijs will serve as committee member for master students Henry Sanchez, Lewis Fitzgerald Campbell (Fiber Science and Apparel Design), and Han Jun Kim (Architcture, Art and Planning)

Jun 5, 2023

Albina Krasykova (BBT AI), Fahad Tahir (BBT AI), and Justin Moore (master student) joined us as the summer crew of the lab!

May 20, 2023

Thijs Roumen received the Faculty Dedication Award voted by (master) students for being the most passionate professor at Cornell Tech!

May 19, 2023

Thijs Roumen will serve as Demo Chair for UIST 2023 and is invited to be on the Best Paper Committee for DIS 2023!

Apr 15, 2023

Shuo Feng, Tobias Weinberg, Zekun Chang (secondary), Bo Liu (secondary), and Ritik Batra (secondary) will join the Matter of Techlab as PhD students next summer! This will be great!!

Apr 10, 2023

Thijs Roumen will be general chair of ACM SCF and will bring the conference to Cornell Tech, NYC!

Mar 15, 2023

Fahad Tahir and Albina Krasykova will join the Matter of Tech lab as summer interns through the BTT AI program this summer!

Feb 4, 2023

Pensalabs borrows the Matter of Tech lab their Pro Wire bending prototype! Great to have cutting-edge machines for our Digital Fabrication class!

Jan 17, 2023

Proud to announce that Albert Han (intern, now first alumnus :)) accepted a PhD position at Indiana University Bloomington! We wish them all the best!

Jan 5, 2023

Thijs is awarded Summa Cum Laude for his dissertation

Dec 19, 2022

Anais Baez joins our team as administrative assistant. Welcome Anais!

Dec 16, 2022

Thijs gives talk at HPI NYC hosted at SAP center by Joann Halpern.

Dec 5, 2022

Finished teaching the first semester of HCI and Design!

Oct 26, 2022

Thijs, Amrit, Ilan, and Ritik go to SCF in Seattle, let us know if you want to catch up!

Sep 23, 2022

Thijs joins as a panelist in UCLA Career Chat hosted by Ruolin Wang and Xiang 'Anthony' Chen

Sep 10, 2022

Our paper "Structure-Preserving Editing of Plates and Volumes for Laser Cutting" was accepted for publication at SCF'22.

Aug 31, 2022

Thijs joins as panelist for the Cornell IS Colloquium on Academic Job Search

Jul 21, 2022

Thijs gives talk at the Empathic Computing Lab and Augmented Human Lab at University of Auckland, NZ hosted by Alaeddin Nassani

Jul, 2022

Hello world! The Matter of Tech Lab was started at Cornell Tech, NYC



StructCode: Leveraging Fabrication Artifacts to Store Data in Laser-Cut Objects (ACM SCF'23)

Mustafa Doga Dogan , Vivian Hsinyueh Chan , Richard Qi, Grace Tang, Thijs Roumen, and Stefanie Mueller

We introduce StructCode, a technique to store machine-readable data in laser-cut objects using their fabrication artifacts. StructCode modifies the lengths of laser-cut finger joints and/or living hinges to represent bits of information without introducing additional parts or materials

Video Recorded Talk Paper acm DL


Structure-Preserving Editing of Plates and Volumes for Laser Cutting (ACM SCF'22)

Thijs Roumen, Ingo Apel, Thomas Kern, Martin Taraz, Ritesh Sharma, Ole Schlueter, Jeffrey Johnson, Dominik Meier, Conrad Lempert, and Patrick Baudisch

We present a 3D editor for laser cutting that extends the range of models that users can manipulate. Our system gives users control over the detailed elements of laser cutting, i.e., individual plates and the associated joints, yet at the same time also allows for efficient editing by means of volumetric tools while preserving the structure of plates in the model.

Video Recorded Talk Paper acm DL


HingeCore: Laser-Cut Foamcore for Fast Assembly (ACM UIST'22)

Muhammad Abdullah, Romeo Sommerfeld, Bjarne Sievers, Leonard Geier, Jonas Noack, Marcus Ding, Christoph Thieme, Laurenz Seidel, Lukas Fritzsche, Erik Langenhan, Oliver Adameck, Moritz Dzingel, Thomas Kern, Martin Taraz, Conrad Lempert, Shohei Katakura, Hany Mohsen Elhassany, Thijs Roumen, and Patrick Baudisch

HingeCore is a novel type of laser-cut structure, the key element of which is what we call finger hinges which we produce by laser-cutting foamcore “half-way”. Our HingeCoreMaker software automatically converts 3D models into such 2D cutting plans. The resulting models are particularly easy and fast to assemble, while also being sturdy.

Video Paper acm DL


FoolProofJoint: Reducing Assembly Errors of Laser Cut 3D Models by Means of Custom Joint Patterns (ACM CHI'22)

Keunwoo Park, Conrad Lempert, Muhammad Abdullah, Shohei Katakura, Jotaro Shigeyama, Thijs Roumen, and Patrick Baudisch

FoolProofJoint is software tool that simplifies the assembly of laser-cut 3D models and reduces the risk of erroneous assembly. FoolProofJoint achieves this by modifying finger joint patterns. Wherever possible, FoolProofJoint makes similar looking pieces fully interchangeable, thereby speeding up the user's visual search for a matching piece. When that is not possible, FoolProofJoint gives finger joints a unique pattern of individual finger placements so as to fit only with the correct piece, thereby preventing erroneous assembly

Video Recorded Talk Paper acm DL


AutoAssembler: Automatic Reconstruction of Laser-Cut 3D Models (ACM UIST'21)

Thijs Roumen, Conrad Lempert, Ingo Apel, Erik Brendel, Markus Brand, Laurenz Seidel, Lukas Rambold, and Patrick Baudisch

AutoAssembler, automatically converts 2D cutting plans to 3D models so users can perform parametric changes on them. AutoAssembler uses a beam search algorithm to search possible ways of assembling plates. It uses joints on these plates to combine them into assembly candidates. It thereby preferably pursues candidates (1) that have no intersecting plates, (2) that fit into a small bounding box, (3) that use plates whose joints fit together well, (4) that do not add many unpaired joints, (5) that make use of constraints posed by other plates, and (6) that conform to symmetry axes of the plates.

Video Recorded Talk Paper acm DL


Roadkill: Nesting Laser Cut Objects for Fast Assembly (ACM UIST'21)

Muhammad Abdullah, Romeo Sommerfeld, Laurenz Seidel, Jonas Noack, Ran Zhang, Thijs Roumen, and Patrick Baudisch

Roadkill is a software tool that converts 3D models to 2D cutting plans for laser cutting, such that the resulting layouts allow for fast assembly. Roadkill achieves this by putting all relevant information into the cutting plan: (1) Thumbnails indicate which area of the model a set of parts belongs to. (2) Parts with exposed finger joints are easy to access, thereby suggesting to start assembly here. (3) Openings in the sheet act as jigs, affording assembly within the sheet. (4) Users continue assembly by inserting what has already been assembled into parts that are immediately adjacent or are pointed to by arrows. Roadkill maximizes the number of joints rendered in immediate adjacency by breaking down models into “subassemblies.” Within a subassembly, Roadkill holds the parts together using break-away tabs. (5) Users complete subassemblies according to their labels 1, 2, 3…, following 1 → 1 links to insert subassemblies into other subassemblies, until all parts come together.

Video Recorded Talk Paper acm DL


Assembler3: 3D Reconstruction of Laser-Cut Models (ACM CHI'21)

Thijs Roumen, Yannis Kommana, Ingo Apel, Conrad Lempert, Markus Brand, Erik Brendel, Laurenz Seidel, Lukas Rambold, Carl Goedecken, Pascal Crenzin, Ben Hurdelhey, Muhammad Abdullah, and Patrick Baudisch

Assembler3 is a software tool that allows users to perform 3D parametric manipulations on 2D laser cutting plans. Assembler3 achieves this by semi-automatically converting 2D laser cutting plans to 3D, where users modify their models using available 3D tools (kyub), before converting them back to 2D. This workflow is 10x faster than using the traditional approach of editing 2D cutting plans directly. Assembler3 converts models to 3D using a 5-step algoritm. Once reconstructed, we expect users to store and share their models in 3D, which can simplify collaboration and thereby empower the laser cutting community to create models of higher complexity.

Video Recorded Talk Paper acm DL


FastForce: Real-Time Reinforcement of Laser-Cut Structures (ACM CHI'21)

Muhammad Abdullah, Martin Taraz, Yannis Kommana, Shohei Katakura, Robert Kovacs, Jotaro Shigeyama, Thijs Roumen, and Patrick Baudisch

FastForce is a software tool that detects structural flaws in laser cut 3D models and fixes them by introducing additional plates into the model, thereby making models up to 52x stronger. By focusing on a specific type of structural issue, i.e., poorly connected sub-structures in closed box structures, fastForce achieves real-time performance (1,000,000x faster than finite element analysis , in the specific case of the wheelbarrow). This allows fastForce to fix structural issues continuously in the background, while users stay focused on editing their models and without ever becoming aware of any structural issues.

Video Recorded Talk Paper acm DL


Kerf-Canceling Mechanisms: Making Laser-Cut Mechanisms Operate Across Different Laser Cutters (ACM UIST'20)

Thijs Roumen, Ingo Apel, Jotaro Shigeyama, Muhammad Abdullah, and Patrick Baudisch

Getting laser-cut mechanisms, such as those in microscopes,robots, vehicles, etc., to work, requires all their components to be dimensioned precisely. This precision, however, tends to be lost when fabricating on a different laser cutter, as it is likely to remove more or less material (aka kerf). We address this with what we call kerf-canceling mechanisms. Kerf-canceling mechanisms replace laser-cut bearings, sliders, gear pairs, etc. Unlike their traditional counterparts, however, they keep working when manufactured on a different laser cutter and/or with different kerf. Kerf-canceling mechanisms achieve this by adding an additional wedge element per mechanism. We have created a software tool Kerf-Canceler that locates traditional mechanisms in cutting plans and replaces them with their kerf-canceling counterparts.

Video Recorded Talk Paper acm DL


Kyub: A 3D Editor for Modeling Sturdy Laser-Cut Objects (ACM CHI'19)

Patrick Baudisch, Arthur Silber, Yannis Kommana, Milan Gruner, Ludwig Wall, Kevin Reuss, Lukas Heilman, Robert Kovacs, Daniel Rechlitz, and Thijs Roumen

We present an interactive editing system for laser cutting called kyub. Kyub allows users to create models efficiently in 3D, which it then unfolds into the 2D plates laser cutters expect. Unlike earlier systems, such as FlatFitFab, kyub affords construction based on closed box structures, which allows users to turn very thin material, such as 4mm plywood, into objects capable of withstanding large forces, such as chairs users can actually sit on. To afford such sturdy construction, every kyub project begins with a simple finger-joint " boxel " structure we found to be capable of withstanding over 500kg of load. Users then extend their model by attaching additional boxels. Boxels merge automatically, resulting in larger, yet equally strong structures. While the concept of stacking boxels allows kyub to offer the strong affordance and ease of use of a voxel-based editor, boxels are not confined to a grid and readily combine with kuyb's various geometry deformation tools.

Video Paper acm DL


SpringFit: Joints and Mounts that Fabricate on Any Laser-Cutter (ACM CHI'19)

Thijs Roumen, Jotaro Shigeyama, Julius Cosmo Romeo Rudolph, Felix Grzelka, and Patrick Baudisch

Joints are crucial to laser cutting as they allow making three-dimensional objects; mounts are crucial because they allow embedding technical components, such as motors. Unfortunately. Unfortunately, mounts and joints tend to fail when trying to fabricate a model on a different laser cutter or from a different material. The reason for this lies in the way mounts and joints hold objects in place, which is by forcing them into slightly smaller openings. Such "press fit" mechanisms unfortunately are susceptible to the small changes in diameter that occur when switching to a machine that removes more or less material ("kerf"), as well as to changes in stiffness, as they occur when switching to a different material.

Video Recording of Talk Paper acm DL


Grafter: remixing 3D printed machines (ACM CHI'18)

Thijs Roumen, Willi Mueller and Patrick Baudisch

We explore how to best support users in remixing a specific class of 3D printed objects, namely those that perform mechanical functions. In our survey, we found that makers remix such machines by manually extracting parts from one parent model and combine them with parts from a different parent model. This approach often puts axles made by one maker into bearings made by another maker or combines a gear by one maker with a gear by a different maker. This approach is problematic, however, as parts from different makers tend to fit poorly, which results in long series of tweaks and test-prints until all parts finally work together. We address this with our interactive system grafter. Grafter does two things. First, grafter largely automates the process of extracting and recombining mechanical elements from 3D printed machines. Second, it enforces a more efficient approach to reuse: it prevents users from extracting individual parts, but instead affords extracting groups of mechanical elements that already work together, such as axles and their bearings or pairs of gears. We call this mechanism-based re-mixing.

Video Recording of Talk Paper acm DL


DualPanto: a haptic device that enables blind users to continuously interact with virtual worlds (ACM UIST'18)

Oliver Schneider, Jotaro Shigeyama, Robert Kovacs, Thijs Roumen, Sebastian Marwecki, Nico Boeckhoff, Daniel Amadeus Gloeckner, Jonas Bounama, Patrick Baudisch

We present a new haptic device that enables blind users to continuously track the absolute position of moving objects in spatial virtual environments, as is the case in sports or shooter games. Users interact with DualPanto by operating the me handle with one hand and by holding on to the it handle with the other hand. Each handle is connected to a pantograph haptic input/output device. The key feature is that the two handles are spatially registered with respect to each other. When guiding their avatar through a virtual world using the me handle, spatial registration enables users to track moving objects by having the device guide the output hand.

Video Recording of Talk Paper acm DL


Mobile Fabrication (ACM UIST'16)

Thijs Roumen, Bastian Kruck, Tobias Duerschmid, Tobias Nack and Patrick Baudisch

We explore the future of fabrication, in particular the vision of mobile fabrication, which we define as "personal fabrication on the go". We explore this vision with two surveys, two simple hardware prototypes, matching custom apps that provide users with access to a solution database, custom fabrication processes we designed specifically for these devices, and a user study conducted in situ on metro trains. Our findings suggest that mobile fabrication is a compelling next direction for personal fabrication. From our experience with the prototypes we derive the hardware requirements to make mobile fabrication technically feasible.

Video Recording of Talk Paper acm DL


Linespace a sensemaking platform for the blind (ACM CHI'16)

Saiganesh Swaminathan, Thijs Roumen, Robert Kovacs, David Stangl, Stefanie Mueller and Patrick Baudisch

For visually impaired users, making sense of spatial information is difficult as they have to scan and memorize content before being able to analyze it. Even worse, any update to the displayed content invalidates their spatial memory, which can force them to manually rescan the entire display. Making display contents persist, we argue, is thus the highest priority in designing a sensemaking system for the visually impaired. We present a tactile display system designed with this goal in mind. The foundation of our system is a large tactile display (140x100cm, 23x larger than Hyperbraille), which we achieve by using a 3D printer to print raised lines of filament. The system's software then uses the large space to minimize screen updates. Instead of panning and zooming, for example, our system creates additional views, leaving display contents intact and thus preserving user's spatial memory.

Video Recording of Talk Paper acm DL


Turkdeck: Physical virtual reality based on people (ACM UIST'15)

Lung-Pan Chen, Thijs Roumen, Hannes Rantzsch , Sven Köhler, Patrick Schmidt, Robert Kovacs, Johannes Jasper, Jonas Kemper and Patrick Baudisch

TurkDeck is an immersive virtual reality system that reproduces not only what users see and hear, but also what users feel. TurkDeck allows creating arbitrarily large virtual worlds in finite space and using a finite set of physical props. The key idea behind TurkDeck is that it creates these physical representations on the fly by making a group of human workers present and operate the props only when and where the user can actually reach them. TurkDeck manages these so-called "human actuators" by displaying visual instructions that tell the human actuators when and where to place props and how to actuate them.

Video Recording of Talk Paper acm DL


OmniVib: Towards Cross-body Spatiotemporal Vibrotactile Notifications for Mobile Phones (ACM CHI'15)

Jessalyn Alvina, Simon Perrault, Thijs Roumen, Shengdong Zhao, Maryam Azh and Morten Fjeld

In this paper, we investigate how users perceive spatiotemporal vibrotactile patterns on the arm, palm, thigh, and waist. Results of the first two experiments indicate that precise recognition of either position or orientation is difficult across multiple body parts. Nonetheless, users were able to distinguish whether two vibration pulses were from the same location when played in quick succession. Based on this finding, we designed eight spatiotemporal vibrotactile patterns and evaluated them in two additional experiments.

Video Recording of Talk Paper acm DL


NotiRing: A Comparative Study of Notification Channels for Wearable Interactive Rings (ACM CHI'15 Short)

Thijs Roumen, Simon Perrault and Shengdong Zhao

We conducted an empirical investigation of wearable interactive rings on the noticeability of four instantaneous notification channels (light, vibration, sound, poke) and a channel with gradually increased temperature (thermal) during five levels of physical activity (laying down, sitting, standing, walking, and running).

Video Recording of Talk Paper acm DL



Thank you for interest in joining the Matter of Tech Lab!
PhD Syllabus: what it is like to PhD with me?
PhD applicants: we plan to extend our group with 2-3 PhD students in 2023! To apply, use this form to share your interests with the team and apply to Information Science or Computer Science at the official Cornell Application System
Master/other students or prospective doctoral interns: we are always interested in creating opportunities to join some of our ongoing projects. Use this form to share your interest. We promise we try to get back to you as soon as possible!

Contact Us

Tata Innovation Center
11 E Loop Rd,
New York, NY 10044
United States of America


2023, Justin Moore (master student)
2023, Nicholas Burka (master student)
2023, Albina Krasykova (undergraduate summer intern, BTT AI)
2023, Fahad Tahir (undergraduate summer intern, BTT AI)
2023, Albert Han (research intern) --> now PhD at Indiana University Bloomington