## 2022/07/21, v6:
- Added a missing \delta t on the second term of the left-hand side of Eq. 14 and in line 10 of Alg. 3.
- Slightly transformed the right-hand side of Eq. 14 so it matches Eq. 13 more closely.
## 2021/12/20, v5:
- Corrected the formula for the friction acceleration (Eq. 24).
## 2021/08/04, v4:
- Removed incorrect h^3 factor in boundary particle volume calculation in Section 3.4.
## 2021/06/18, v3:
- Fixed multiple typos.
- Added missing dot product signs in Eq. 6, Eq. 8, Eq. 24 and Eq. 25.
- Updated Fig. 3 and additional analysis video to fix right-most cylinder not turning invisible when turning inactive.
- Added references to Weiler et al. [2016] and Bouaziz et al. [2014].
## 2020/07/20, v2:
- Extended Eq. 17 to clarify the implementation.
## 2020/04/27, v1:
- Author's version of the manuscript that was submitted to SIGGRAPH 2020.