Thijs Roumen

I am on the academic job market looking for faculty positions, contact me if you have interesting openings I should consider applying to.

Portable Laser-Cutting

My research is in digital fabrication, a subfield of human-computer interaction (HCI). In my PhD work, I have been focusing on a specific fabrication technology, i.e., software systems for laser cutting. My specific objective is to create a technological basis that allows designers and engineers of laser cut 3D models to build on each other's work, as I see this as being instrumental in allowing this nascent field to increase in model complexity and adoption—a progression that is currently held back by the use exchange formats that disregard mechanical differences between machines and therefore overlook implications with respect to how well parts mechanically fit together (aka engineering fit). In my PhD, I thus explore better ways for representing models.

I approached this in three takes: first I aimed to preserve the original formats and built software tools (SpringFit and KerfCanceler) to mitigate their limitations. I then investigated representing models as 3D models instead of 2D cutting plans by building and extending 3D modeling environments (kyub). And finally, I wrote tools to convert the problematic 2D cutting plans to 3D models automatically (autoAssembler and assembler3), enabling users to customite and build on the existing models.

Full Papers at CHI/UIST

[13] AutoAssembler: Automatic Reconstruction of Laser-Cut 3D Models

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

In Proceedings of UIST '21 (full paper)

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. This works for models that have at least one edge joint (finger or t-joint). In our technical evaluation, we imported 66 models using autoAssembler. AutoAssembler assembled 79% of those models fully automatically; another 18% of models required on average 2.7 clicks of post-processing, for an overall success rate of 97%.

paper video recording of talk (UIST21) acm DL

[12] Roadkill: Nesting Laser Cut Objects for Fast Assembly

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

In Proceedings of UIST '21 (full paper)

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.

paper video recording of talk (UIST21) acm DL

[11] Assembler3: 3D Reconstruction of Laser-Cut Models

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

In Proceedings of CHI '21 (full paper)

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.

paper videorecording of talk (CHI'21) acm DL

[10] FastForce: Real-Time Reinforcement of Laser-Cut Structures

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

In Proceedings of CHI '21 (full paper)

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.

paper video recoding of talk (CHI'21) acm DL

[9] Kerf-Canceling Mechanisms: Making Laser-Cut Mechanisms Operate Across Different Laser Cutters

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

In Proceedings of UIST '20 (full paper)

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.

paper video recording of virtual talk (UIST20) acm DL

[8] SpringFit: Joints and Mounts that Fabricate on Any Laser-Cutter

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

In Proceedings of UIST '19 (full paper)

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.

We present a software tool called springFit that resolves this problem by replacing the problematic press fit-based mounts and joints with what we call cantileverbased mounts and joints.

paper video recording of talk (UIST19) acm DL

[7] Kyub: A 3D Editor for Modeling Sturdy Laser-Cut Objects

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

In Proceedings of CHI '19 (full paper)

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.

paper video acm DL

[6] grafter: remixing 3D printed machines

Thijs Roumen, Willi Mueller and Patrick Baudisch

In Proceedings of CHI '18 (full paper)

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.

paper video talk recording acm DL

[5] Mobile Fabrication

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

In Proceedings of UIST '16 (full paper)

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.

paper video talk recording acm DL

[4] DualPanto: a haptic device that enables blind users to continuously interact with virtual worlds

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

In Proceedings of UIST '18 (full paper)

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.

paper video acm DL

[3] Linespace a sensemaking platform for the blind

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

In Proceedings of CHI '16 (full paper)

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

paper video talk recording acm DL

[2] Turkdeck: Physical virtual reality based on people

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

In Proceedings of UIST '15 (full paper)

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.

paper video recording of talk acm DL

[1] OmniVib: Towards Cross-body Spatiotemporal Vibrotactile Notifications for Mobile Phones

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

In Proceedings of CHI '15 (full paper)

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.

paper video recording of talk acm DL

Short CHI Papers

[1] NotiRing: A Comparative Study of Notification Channels for Wearable Interactive Rings

Thijs Roumen, Simon Perrault and Shengdong Zhao

In Proceedings of CHI '15 (short paper)

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). Results showed that vibration was the most reliable and fastest channel to convey notification, followed by poke and sound which shared similar noticeability. The noticeability of these three channels was not affected by the level of physical activity. The other two channels, light and thermal, were less noticeable and were affected by the level of physical activity. Our post-experimental survey indicates that while noticeability has a significant influence on user preference, each channel has its own unique advantages that make it suitable for different notification scenarios.

paper video recording of talk acm DL

Invited talks

2021-12-16 University of Michigan invited by Anhong Guo
2021-12-09 University of Virginia invited by Seongkook Heo
2021-12-03 UCLA, California invited by Yang Zhang
2021-12-01 UCSD, California invited by Jane E
2021-11-29 Harvard, Cambridge invited by Elena Glassman
2021-11-26 NTU, Taiwan invited by Lung-Pan Cheng
2021-08-05 LMU Munchen, Germany invited by Albrecht Schmidt
2021-07-05 University of Calgary, Canada invited by Ryo Suzuki
2021-06-15 University of Chicago, Illinois invited by Pedro Lopes
2021-05-20 University of Cape Town, South Africa invited by Melissa Delsmore
2021-05-19 Darthmouth College, New Hamshire invited by Xing-Dong Yang
2021-05-18 University of Tokyo, Japan invited by Nobuyuki Umetani
2021-05-11 MIT vision and graphics seminar invited by
2021-05-07 University of Waterloo, Canada invited by Oliver Schneider
2021-05-04 MIT Center for Bits and Atoms invited by Neil Gershenfeld
2021-05-04 KAIST, South Korea invited by Andrea Bianchi
2021-04-30 Hasselt University, Belgium invited by Raf Ramakers
2021-04-27 University of Copenhagen, Denmark invited by Daniel Ashbrook
2021-04-22 University of Maryland, Washington invited by Huaishu Peng
2021-04-21 Carnegie Mellon University, Pittsburgh invited by Alexandra Ion
2021-04-14 University of Washington, Seattle invited by James Fogarty
2021-04-13 SIGCHI seminar Paris invited by Samuel Huron
2021-03-17 University College London, UK invited by Nicolai Marquardt
2021-02-25 National University of Singapore invited by Shengdong Zhao
2021-02-24 University of Toronto, Canada invited by Tovi Grossman
2021-02-23 Ulm University, Germany invited by Enrico Rukzio
2021-02-18 University of Bristol, UK invited by Anne Roudaut
2021-02-16 University of Colorado, Boulder invited by Ellen Do
2021-02-04 Saarland University, Germany invited by Juergen Steimle
2021-01-29 MIT Media Lab invited by Hiroshi Ishii
2020-11-17 MIT CSAIL invited by Arvind Satyanarayan
2020-11-16 A&M University of Texas invited by Jeeeun Kim
2020-10-09 University of California, Merced invited by Marcelo Kallmann
2019-01-17 Kolding Design School invited by Jonas Leonas
2018-10-24 Dagstuhl Seminar on Computational Aspects of Fabrication, invited by Bernd Bickel

Volunteering

Member of program committees (full papers):

  • UIST'21
  • CSCW'22
  • TEI'21, '22
  • MobileHCI'21
  • DesForm'19

Member of organizing committees:

  • Student Innovation Contest Chair UIST'22
  • Student Design Contest Chair TEI'22
  • Local Arrangement Chair UIST'18

Reviewer:

  • CHI 15-22
  • UIST 15-21
  • and other conferences

Special recognitions for reviews:

  • [20] CHI 2022,2x
  • [18] UIST 2021,
  • [17] CHI 2021, 2x
  • [15] UIST 2020, 3x
  • [12] CHI Play 2020
  • [11] CHI 2020, 2x
  • [9]  CHI 2018, 2x
  • [7]  CHI 2016, 2x
  • [5]  CSCW 2015
  • [4]  CHI Play 2015
  • [3]  CHI 2015, 2x
  • [1]  CHI Play 2014

Community:

  • Moderator for CHI meta
  • Chairman of German Networking Event at CHI (2017,18,19)

Other

World Major Marathon Finisher at 2019 Berlin Marathon (3:16:27)
2018 New York Marathon for Run For Life