Publications

Thumbnail of Designing Volumetric Truss Structures for Computational Fabrication
Designing Volumetric Truss Structures for Computational Fabrication

Rahul Arora, Alec Jacobson, Timothy R. Langlois, Karan Singh, and David I.W. Levin
In Graphics Interface 2018 (GI '18) Posters 2018

Abstract, BibTeX, Poster, Abstract

We present the first algorithm for designing volumetric Michell Trusses. Our method uses a parametrization approach to generate trusses made of structural elements aligned with the primary direc- tion of an objects stress field. Such trusses exhibit high strength-to- weight ratio while also being aesthetically pleasing. Unlike tradi- tional approaches to structural optimization, our method produces trusses that can be edited as a post process but retain structural opti- mality. We also demonstrate the structural robustness of our designs via mechanical testing. Our algorithm permits an exciting combina- tion of control and structural soundness which we believe serves as an important compliment to existing structural optimization tools and as a novel standalone design tool itself.

@inproceedings{Arora:michell:2018,
 author = {Arora, Rahul and Jacobson, Alec and Langlois, Timothy R. and Singh, Karan and Levin, David I.W.},
 title = {Designing Volumetric Truss Structures for Computational Fabrication},
 booktitle = {In Graphics Interface 2018 Posters},
 series = {GI '18 Posters},
 year = {2018},
 location = {Toronto, Ontario, Canada},
 numpages = {2},
 publisher = {ACM},
 address = {New York, NY, USA}
}
Thumbnail of SymbiosisSketch: Combining 2D and 3D Sketching for Designing Detailed 3D Objects in Situ
SymbiosisSketch: Combining 2D and 3D Sketching for Designing Detailed 3D Objects in Situ

Rahul Arora, Rubaiat Habib, Tovi Grossman, George Fitzmaurice, and Karan Singh
Proceedings of the ACM SIGCHI Comference on Human Factors in Computing Systems 2018

Abstract, BibTeX, DOI, Paper, Video, Talk at CHI

We present SymbiosisSketch, a hybrid sketching system that combines drawing in air (3D) and on a drawing surface (2D) to create detailed 3D designs of arbitrary scale in an augmented reality (AR) setting. SymbiosisSketch leverages the complementary affordances of 3D (immersive, unconstrained, life-sized) and 2D (precise, constrained, ergonomic) interactions for in situ 3D conceptual design. A defining aspect of our system is the ongoing creation of surfaces from unorganized collections of 3D curves. These surfaces serve a dual purpose: as 3D canvases to map strokes drawn on a 2D tablet, and as shape proxies to occlude the physical environment and hidden curves in a 3D sketch. SymbiosisSketch users draw interchangeably on a 2D tablet or in 3D within an ergonomically comfortable canonical volume, mapped to arbitrary scale in AR. Our evaluation study shows this hybrid technique to be easy to use in situ and effective in transcending the creative potential of either traditional sketching or drawing in air.

@inproceedings{Arora:SymbiosisSketch:2018,
 author = {Arora, Rahul and Kazi, Rubaiat Habib and Grossman, Tovi and Fitzmaurice, George and Singh, Karan},
 title = {SymbiosisSketch: Combining 2D \& 3D Sketching for Designing Detailed 3D Objects in Situ},
 booktitle = {Proceedings of the 2018 CHI Conference on Human Factors in Computing Systems},
 series = {CHI '18},
 year = {2018},
 location = {Montreal, Quebec, Canada},
 url = {http://dx.doi.org/10.1145/3173574.3173759},
 doi = {10.1145/3173574.3173759},
 numpages = {15},
 publisher = {ACM},
 address = {New York, NY, USA}
}
Thumbnail of Experimental Evaluation of Sketching on Surfaces in VR
Experimental Evaluation of Sketching on Surfaces in VR

Rahul Arora, Rubaiat Habib, Fraser Anderson, Tovi Grossman, Karan Singh, and George Fitzmaurice
Proceedings of the ACM SIGCHI Comference on Human Factors in Computing Systems 2017

Abstract, BibTeX, DOI, Paper, Video, Data and code, Slides

Sketching in immersive 3D virtual reality (VR) environments has great potential for a variety of interactive 3D design applications. Precisely sketching the intended strokes in mid-air, however, can be a challenge. In this paper, we present a set of controlled studies to analyze the factors affecting human ability to sketch freely in a 3D VR environment. In our first study, we directly compare traditional sketching on a physical surface to sketching in VR, with and without a physical surface to rest the stylus on. Our results indicate that the lack of a physical drawing surface is a major cause of inaccuracies in VR drawing, and that the effect is dependent on the orientation of the drawing surface. In a second experiment, we evaluate the extent to which visual guidance can compensate for the loss of sketching precision in VR. We found that while additional visual guidance improves positional accuracy, it can be detrimental to the aesthetic quality of strokes. We conclude by distilling our experimental findings into design guidelines for sketching tools in immersive 3D environments.

@inproceedings{Arora:vrSketching:2017,
 author = {Arora, Rahul and Kazi, Rubaiat Habib and Anderson, Fraser and Grossman, Tovi and Singh, Karan and Fitzmaurice, George},
 title = {Experimental Evaluation of Sketching on Surfaces in VR},
 booktitle = {Proceedings of the 2017 CHI Conference on Human Factors in Computing Systems},
 series = {CHI '17},
 year = {2017},
 location = {Denver, Colorado, USA},
 DOI = {10.1145/3025453.3025474}
 numpages = {12},
 publisher = {ACM},
 address = {New York, NY, USA}
}
Thumbnail of Sketchsoup: Exploratory Ideation using Design Sketching
Sketchsoup: Exploratory Ideation using Design Sketching

Rahul Arora, Ishan Darolia, Vinay P. Namboodiri, Karan Singh, and Adrien Bousseau
Computer Graphics Forum 2017

Abstract, BibTeX, DOI, Paper, Video, Comparisons Video, Slides

A hallmark of early stage design is a number of quick-and-dirty sketches capturing design inspirations, model variations, and alternate viewpoints of a visual concept. We present SketchSoup, a workflow that allows designers to explore the design space induced by such sketches. We take an unstructured collection of drawings as input, along with a small number of user-provided correspondences as input. We register them using a multi-image matching algorithm, and present them as a 2D interpolation space. By morphing sketches in this space, our approach produces plausible visualizations of shape and viewpoint variations despite the presence of sketch distortions that would prevent standard camera calibration and 3D reconstruction. In addition, our interpolated sketches can serve as inspiration for further drawings, which feed back into the design space as additional image inputs. SketchSoup thus fills a significant gap in the early ideation stage of conceptual design by allowing designers to make better informed choices before proceeding to more expensive 3D modeling and prototyping. From a technical standpoint, we describe an end-to-end system that judiciously combines and adapts various image processing techniques to the drawing domain—where the images are dominated not by color, shading and texture, but by sketchy stroke contours.

@article{Arora:SketchSoup:2017,
 author = {Arora, Rahul and Darolia Ishan and Namboodiri, Vinay P. and Singh, Karan and Bousseau, Adrien},
 title = {SketchSoup: Exploratory Ideation using Design Sketches},
 journal = {Computer Graphics Forum},
 year = {2017},
 url = {http://dx.doi.org/10.1111/cgf.13081},
 doi = {10.1111/cgf.13081},
 publisher = {Wiley}
}
Thumbnail of Derandomizing Isolation Lemma for K<sub>3,3</sub>-free and K<sub>5</sub>-free Bipartite Graphs
Derandomizing Isolation Lemma for K3,3-free and K5-free Bipartite Graphs

Rahul Arora, Ashu Gupta, Rohit Gurjar, and Raghunath Tewari
Symposium on Theoretical Aspects of Computer Science (STACS) 2016

Abstract, BibTeX, DOI, Paper, Full version (ECCC)

The perfect matching problem has a randomized NC algorithm, using the celebrated Isolation Lemma of Mulmuley, Vazirani and Vazirani. The Isolation Lemma states that giving a random weight assignment to the edges of a graph ensures that it has a unique minimum weight perfect matching, with a good probability. We derandomize this lemma for K3,3-free and K5-free bipartite graphs. That is, we give a deterministic log-space construction of such a weight assignment for these graphs. Such a construction was known previously for planar bipartite graphs. Our result implies that the perfect matching problem for K3,3-free and K5-free bipartite graphs is in SPL. It also gives an alternate proof for an already known result—reachability for K3,3-free and K5-free graphs is in UL.

@InProceedings{arora_et_al:LIPIcs:2016:5711,
  author ={Rahul Arora and Ashu Gupta and Rohit Gurjar and Raghunath Tewari},
  title =,
  booktitle ={33rd Symposium on Theoretical Aspects of Computer Science (STACS 2016)},
  pages ={10:1--10:15},
  series ={Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN ={978-3-95977-001-9},
  ISSN ={1868-8969},
  year ={2016},
  volume ={47},
  editor ={Nicolas Ollinger and Heribert Vollmer},
  publisher ={Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik},
  address ={Dagstuhl, Germany},
  URL ={http://drops.dagstuhl.de/opus/volltexte/2016/5711},
  URN ={urn:nbn:de:0030-drops-57116},
  doi ={http://dx.doi.org/10.4230/LIPIcs.STACS.2016.10},
  annote ={Keywords: bipartite matching, derandomization, isolation lemma, SPL, minor-free graph}
}

Interests

In my free time, I like to play squash and badminton and to perform culinary epxeriments. Michael Tao has recently gotten me into lifting.
I'm also learning how to sketch better. Some of my sketches (making it very clear that I'm learning) can be found here. Please note that some of these sketches may be considered NSFW.
I'm fluent in Hindi and English, and am trying (not hard enough) to improve my French and Punjabi.

Contact

arorar@dgp.toronto.edu

Other: arorar@cs.toronto.edu