PrimeSim is an action-conditioned multiview world model that uses progressive training, unified action representations, view-aware attention, and hierarchical memory to enable consistent, long-horizon robot simulation and policy optimization.
A robot world model that serves as a simulator must do more than generate plausible videos: it must faithfully follow commanded actions, maintain consistency across camera views, and sustain coherent long-horizon rollouts. We present PrimeSim, an action-conditioned, multiview world model simulator that addresses these challenges through progressive midtraining and posttraining. Starting from a pretrained video generator, we midtrain on 30,110 hours of robot demonstrations spanning 22 platforms. To improve action following, we introduce a unified cross-embodiment action representation and frame-aligned dual-path conditioning to strengthen action-frame correspondence. To maintain multiview…
action-conditioned world modelprogressive midtrainingcross-embodiment action representationdual-path conditioningview-aware interleaved attentionautoregressive simulatorself-rollout traininghierarchical temporal memoryGRPO-based policy optimization
- Upvotes
- 8
- Authors
- 13
- Published
- Nov 3, 2026
Summary and abstract excerpt via Hugging Face Papers ↗ · arXiv.