Amritansh Kwatra, Tobias Weinberg, Ilan Mandel, Ritik Batra, Peter He, Francois Guimbretiere, and Thijs Roumen

We present SplatOverflow, a workflow to support end-users, community members and manitainers asynchronously troubleshoot hardware issues.

Project page • Video • Paper

Tobias Weinberg, Kowe Kadoma, Ricardo E. Gonzalez Penuela, Stephanie Valencia, and Thijs Roumen

We study how AI-powered AAC interfaces can help users with speech disabilities deliver timely, humorous comments. This study highlights design insights to improve expressivity and timing in AAC technology.

Project page • Video • Paper

Shuo Feng , Lavenda Yifan Shan , Xuening Wang , Ritik Batra, and Thijs Roumen

Designers of physical objects make assumptions on the material and fabrication workflow early in the design process. Recovering from bad assumptions is hard, because the design and resulting CAD model are locked-in to those assumptions. We present CAMeleon, a software tool to interactively explore fabrication workflows at any stage of the CAD process.

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Shuo Feng, Bo Liu, Yifan Shan, Ofer Berman, Harald Haraldsson, and Thijs Roumen

We present Y-AR, a Computer Aided Design (CAD) interface for 3D wire bending. Y-AR uses mixed reality to let designers create structures that physically connect to objects in the environment. The interface incorporates springs as design primitives which (1) apply forces to hold objects, and (2) counter-act dimensional inaccuracies inherently caused by mid air modeling and measurement errors in AR.

Project Page • Video • Paper

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