  Tactile sensing has seen a rapid adoption with the advent of vision-based
tactile sensors. Vision-based tactile sensors provide high resolution, compact
and inexpensive data to perform precise in-hand manipulation and human-robot
interaction. However, the simulation of tactile sensors is still a challenge.
In this paper, we built the first fully general optical tactile simulation
system for a GelSight sensor using physics-based rendering techniques. We
propose physically accurate light models and show in-depth analysis of
individual components of our simulation pipeline. Our system outperforms
previous simulation techniques qualitatively and quantitative on image
similarity metrics. Our code and experimental data is open-sourced at
https://labs.ri.cmu.edu/robotouch/tactile-optical-simulation/
