Abstract: 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 high-level goal is to make laser cutting relevant to millions of users, instead of to the 
thousands of tech enthusiasts who currently use this technology. 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 of 
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 this talk, I thus explore better ways for representing models.

I started my PhD work by preserving the 2D format currently in use, by writing software tools 
that replace machine-specific features (press-fit and loose-fit) with more forgiving mechanical 
elements, i.e., specific types of springs (full paper ACM UIST’19) and a novel type of bearing 
I engineered (full paper ACM UIST’20). While these allow users to reproduce 3D models across 
machines, the field needs access to parametric modifications in 3D to build on work of others. I 
created elements of a software system that allows modeling laser-cut models in 3D (full paper 
CHI’19). Users export the 3D models to their specific machine, which solves the portability 
question. It does raise a question of what to do with the vast amount of existing 2D cutting plans. 
To handle this legacy, I have written a series of software tools that allow users to convert existing
2D cutting plans into 3D models, by reconstructing the 3D nature of the model using a set of 
interactive manual tools (full paper CHI’20), I then progressed to an automatic approach based 
on efficient graph algorithms (full paper UIST’21)

I have integrated these tools into the above-mentioned system (kyub, 140,000 lines of code). To 
test each of my technologies with hundreds of models from this model repository, and by running 
workshops with school classes to see that my software lets users progress to more complex 
models such as furniture and guitars. This system integration also allows me to push forward to 
actual use. I believe that by simplifying sharing and re-use and the resulting increase in model 
complexity, this line of work and the resulting system will ultimately help personal fabrication
scale past the maker phenomenon it currently is and towards a mainstream phenomenon—the 
same way that other fields, such as print (postscript) and ultimately computing itself (portable 
programming languages, etc.) reached mass adoption. 

Bio: Thijs Roumen is a PhD candidate in Human Computer Interaction in the lab of Patrick Baudisch, 
Hasso Plattner Institute in Potsdam, Germany. He received his MSc from the University of 
Southern Denmark, Sønderborg in 2013 and BSc from the Technical University of Eindhoven, 
Netherlands in 2011. Between the PhD and master he worked at the National University of 
Singapore as a Research Assistant with Shengdong Zhao. His research interests are in personal 
fabrication, digital collaboration and enabling increased complexity for laser cutting. His papers 
are published as full papers in top-tier ACM conferences CHI and UIST. He serves on several 
ACM program committees including ACM UIST and CSCW.