Office: 6-225E Keller Hall

Phone: (612) 625-2013

Email: narain@umn.edu

I'm an assistant professor in the Department of Computer Science and Engineering at the University of Minnesota, Twin Cities. My research focuses on numerical methods and mathematical models for physics-based animation and computer graphics. I'm also interested in applications to design, robotics, and scientific computing.

Previously, I received a B.Tech. from the Indian Institute of Technology Delhi and an M.S. and a Ph.D. from the University of North Carolina at Chapel Hill advised by Ming C. Lin, and did a postdoc at the University of California, Berkeley working with James F. O'Brien.

I'm looking for enthusiastic students who think physics is cool and aren't afraid of a little maths. Take a look at some of my research areas below, and if any of them sound exciting or you have ideas of your own, get in touch!

I will be teaching *CSci 5980/8980: Physics-Based Animation* in fall 2015. I'll set up a course web page soon, but in the meantime, here's the flyer describing the course content, format, and prerequisites.

At Berkeley, I gave two guest lectures on fluid simulation in *CS 184: Foundations of Computer Graphics* in fall 2013. Here are the slides: (1) Introduction and particle-based fluids, (2) grid-based fluids.

At UNC, I taught *COMP 116: Introduction to Scientific Computing* in the first summer session, 2011.

**Adaptive remeshing:** Lots of physical phenomena show fine localized detail, from folds and wrinkles in cloth to crack patterns in shattering objects. Naturally, we'd like to refine the mesh resolution where there is detail and use coarser elements in smooth regions. The tricky part is anticipating where detail is *going* to emerge and refining sufficiently in advance, so you don't lose all the interesting dynamics.

- R. Narain, A. Samii, and J.F. O'Brien. "Adaptive Anisotropic Remeshing for Cloth Simulation". SIGGRAPH Asia 2012.
- R. Narain, T. Pfaff, and J.F. O'Brien. "Folding and Crumpling Adaptive Sheets". SIGGRAPH 2013.
- T. Pfaff, R. Narain, J.M. de Joya, and J.F. O'Brien. "Adaptive Tearing and Cracking of Thin Sheets". SIGGRAPH 2014.

**Fluids etc.:** Computer graphics has a rich history of techniques for simulating smoke, water, and other Newtonian fluids. I like to think about ways to simulate nontraditional fluid-like substances — like sand and oobleck — and to simulate fluids in nontraditional ways — like vorticity-based and boundary element methods.

- R. Narain, J. Sewall, M. Carlson, and M.C. Lin. "Fast Animation of Turbulence Using Energy Transport and Procedural Synthesis". SIGGRAPH Asia 2008.
- R. Narain, A. Golas, and M.C. Lin. "Free-Flowing Granular Materials with Two-Way Solid Coupling". SIGGRAPH Asia 2010.
- A. Golas, R. Narain, J. Sewall, P. Krajcevski, P. Dubey, and M.C. Lin. "Large-Scale Fluid Simulation using Velocity-Vorticity Domain Decomposition". SIGGRAPH Asia 2012.

**Crowd simulation:** Crowds of pedestrians can in certain situations be well approximated as a continuous fluid-like system, particularly when the crowd is large and dense. In these cases we can apply the tools of continuum mechanics to model the behaviour of the crowd, enabling efficient simulations and revealing new insights.

- R. Narain, A. Golas, S. Curtis, and M.C. Lin. "Aggregate Dynamics for Dense Crowd Simulation". SIGGRAPH Asia 2009.
- A. Golas, R. Narain, and M.C. Lin. "Hybrid Long-Range Collision Avoidance for Crowd Simulation". I3D 2013 and
*TVCG*, 2014. - A. Golas, R. Narain, and M.C. Lin. "Continuum Modeling of Crowd Turbulence".
*Physical Review E*, 2014.

Here's my full list of publications.