Publications

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 (to appear) 2017

Abstract, BibTeX, DOI, Paper, Video

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 (to appear) 2017

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

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, Vany 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