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    "story_id": "mp-2026-08-07-004",
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    "headline": "A Plausible Motion Still Used the Wrong Physics",
    "slug": "a-plausible-motion-still-used-the-wrong-physics",
    "dek": "GAUGE measures simulators and video world models against calibrated trajectories instead of judging whether their output merely looks right.",
    "summary": "GAUGE measures simulators and video world models against calibrated trajectories instead of judging whether their output merely looks right.",
    "body_text": "GAUGE collects 22 controlled task families spanning rigid bodies, cables, textiles and volumetric deformable objects. Tests of three physics engines found no uniformly faithful system, with the largest gaps in impulsive contact, fast textile motion and volumetric deformation; six image-to-video models sometimes reproduced the expected equation form while recovering wrong acceleration, momentum transfer or oscillation timing. The results are benchmark diagnostics, not a ranking of every simulator or world model.",
    "why_it_matters": "GAUGE measures simulators and video world models against calibrated trajectories instead of judging whether their output merely looks right.",
    "limitations": [
      "The results are benchmark diagnostics, not a ranking of every simulator or world model."
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        "text": "GAUGE measures simulators and video world models against calibrated trajectories instead of judging whether their output merely looks right.",
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        "qualification": "The results are benchmark diagnostics, not a ranking of every simulator or world model."
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    "tags": [
      "world models",
      "physics engines",
      "robotics",
      "evaluation"
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  "sources": [
    {
      "source_id": "source-2026-08-07-004",
      "title": "arXiv preprint 2608.05948",
      "publisher": "arXiv",
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    "name": "The Machine Press",
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    "title": "A Plausible Motion Still Used the Wrong Physics",
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