“Stabilizing Impossible Collisions with Loki” by Zhai, Schweickart, Haryono, Ilinov and Merlo
Conference:
Type(s):
Title:
- Stabilizing Impossible Collisions with Loki
Session/Category Title:
- Emotions, Explosions, and Epic Simulations
Presenter(s)/Author(s):
Moderator(s):
Abstract:
We present a suite of techniques from our in-house simulation framework, Loki, addressing the pervasive challenge of collision instabilities in character effects, particularly in cases where nonphysical pinching prevents collision resolution. We introduce a proximity-tolerant mode for contact projection that trades collision residual for stability, a compliant kinematic mechanism for on-demand gap expansion, and contact-aware strain limiting to prevent penetrations while enforcing target edge lengths. Additionally, we showcase our tools for collider management, including hierarchical collision exclusion, one-sided collision handling, and paintable collision thickness maps. These techniques collectively demonstrate a robust and intuitive workflow for combining physically based collisions with challenging production animations.
References:
[1] Steve Lesser, Alexey Stomakhin, Gilles Daviet, Joel Wretborn, John Edholm, Noh-Hoon Lee, Eston Schweickart, Xiao Zhai, Sean Flynn, and Andrew Moffat. 2022. Loki: A Unified Multiphysics Simulation Framework for Production. ACM Trans. Graph. 41, 4, Article 50 (jul 2022), 20 pages.
[2] Minchen Li, Danny M. Kaufman, and Chenfanfu Jiang. 2021. Codimensional incremental potential contact. ACM Trans. Graph. 40, 4, Article 170 (July 2021), 24 pages.
