Section

World action models

Policies that start from a video or world-model backbone and learn to predict both how a scene changes and what the robot should do.

A world action model is a robot policy built on a backbone that was first trained to predict video or future world state, then adapted so it also outputs actions. That definition is the one this site uses in what is a world action model?, following Reuss, NVIDIA Technical Blog (15 June 2026).

Reuss sorts WAMs by what they predict. Inverse dynamics: Generates the future video, then infers the actions that would produce it. On this register: UniPi, Video Prediction Policy, mimic-video, LingBot-VA, DVA. Joint prediction: Emits video and actions together. On this register: GR-1, GENIMA, Unified Video Action, Cosmos Policy, DreamZero. Representation-only: Uses the video backbone's internal features and skips generating frames. On this register: Fast-WAM, Odyssey-3. Latent actions: Learns actions as hidden codes from video. On this register: DreamDojo, Being-H0.7. Hybrid: Mixes the vision-language-action (VLA) and world action model recipes. On this register: Motus, BagelVLA, Cortex 2.0.

Those rows are the 17 models in the register. Each card links claims to the paper, project page or official repo they came from. A dash means the field is unconfirmed. Classification follows Reuss's three axes — what the model predicts, how actions enter, and how the parts are wired — checked against the model's own source.

Two results from that map are worth keeping attached to their sources. On RoboArena, a distributed real-world comparison of generalist policies (Atreya et al., RoboArena (2025)), Reuss's April 2026 snapshot puts NVIDIA's DreamZero at 1,750 Elo against 1,622 for Physical Intelligence's π0.5. Fast-WAM is the register's representation-only row: its paper reports 190 ms latency by skipping video generation at test time. Fig. 4, on one real towel-folding task on an RTX 5090D, puts Fast-WAM-Joint at 580 ms, Fast-WAM-IDM at 810 ms, and π0.5 at 180 ms. Those 580 / 810 ms figures are Fast-WAM's own variants, not WAMs in general.

Reuss expects WAMs to become the second main recipe for robot foundation models, and the eventual winner to be a hybrid. This section holds news filed under that recipe. The register is the backlink engine; this page is the stream.

On the register

Stories

  1. Odyssey-3 tests a video world model as a robot backbone

    Odyssey-3 is a video world model that Odyssey says can also run robot arms, humanoids and cars. We check the claimed robot results against Physics-IQ Verified.

  2. WAMsVLAs1 min read

    NVIDIA researcher maps world action models as robotics' second recipe

    Moritz Reuss's long post sorts more than a dozen models into three paradigms, and predicts the field will end up with VLA–WAM hybrids.

  3. WAMsBenchmarks1 min read

    The speed problem: why video-generating world action models are slower than VLAs

    Imagining the future in pixels before acting costs hundreds of milliseconds. Representation-only designs try to keep the knowledge and skip the rendering.

  4. What is a world action model?

    A robot policy that starts from a model pretrained to predict video, then learns to act. Here is how it works, how it differs from a VLA, and what it costs.