A Physics Engine with Incremental Rollback for Multiplayer Games
Easel has developed a custom physics engine that enables large-scale multiplayer games by only snapshotting and rolling back objects that change each frame, significantly reducing computational load. This advancement allows for complex environments, such as a full spaceship in a game, to run efficiently without requiring the entire world state to be processed every frame. The engine includes optimized features like immediate sleep states, efficient spatial indexing, and accurate stepping mechanics to enhance performance and gameplay feel.
- ▪The new physics engine only snapshots and rolls back objects that change each frame, reducing the workload by a factor of 30-50x.
- ▪Objects are put to sleep immediately when velocity reaches zero, and entire stacks stay awake only if forces are unbalanced.
- ▪The engine uses a Bounding Volume Hierarchy (BVH) that supports incremental rebalancing and category-based collision filtering for faster queries.
- ▪Stepping mechanics prevent unwanted bounce-back after collisions without sacrificing knockback from impacts like fireballs.
- ▪The system is designed specifically for Easel’s predictive multiplayer architecture, enabling large, interactive game worlds.
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A Physics Engine with Incremental RollbackMay 1, 2026 · 9 min readraysplaceinspaceCreator of EaselWe want Easel to be powerful enough to make the kinds of games you would play for hours. Popular multiplayer games like Among Us let you walk around an entire spaceship, completing tasks and evading impostors. Unfortunately, up to this point, games of that scale were out of reach for Easel, because the off-the-shelf physics engine would have to snapshot and roll back the entire world to support Easel's predictive multiplayer architecture. It's too much to do every frame. Until this point, you were required to keep your world small. But not anymore! Easel's new custom-built physics engine only snapshots and rolls back the parts of the world that change.
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Excerpt limited to ~120 words for fair-use compliance. The full article is at Easel.
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