Gym-Anything for Robotics: Scaling physical simulations with digital agents
Abstract
Realistic, fast robotics simulations could enable large-scale training of embodied AI models that transfer to the real world. However, despite decades of progress, available simulations cover only a narrow range of real-world tasks and physical phenomena. The core bottleneck is that creating better simulations requires significant expert effort and therefore does not scale. To address this, we introduce Gym-Anything for Robotics, a framework in which coding agents create realistic robotics simulations. Our core insight is that simulation creation is a coding agent task, so improvements in coding agents translate directly into richer and more faithful simulations. We select simulations based on U.S. GDP data to cover economically valuable physical work, define what makes a good simulation and a good task, and develop an adversarial creation-audit loop that checks each simulation and task against these definitions. Using this pipeline, we build RoboWorld, a set of 25 simulations with 25 test and 175 training RL environments of varying difficulty. Even the best frontier models fail on every RoboWorld test task, achieving an average reward of only 0.06. Building on RoboWorld, we introduce several new ways for frontier models to improve, including in-context learning across repeated attempts, a privileged teacher that reads the simulator state and teaches a student in context, self-assisted learning from the model's own privileged experience, and code policies that generate demonstrations across varied scenes to train vision-language-action models (VLAs) such as $π_{0.5}$. Each of these substantially improves performance. We release our pipeline, RL environments, and benchmark to facilitate future research. Code and data are available at https://gym-anything.github.io/robotics
The following analysis is generated by AI and may contain errors. It is separate from the authors’ abstract and is not peer review.
Research summary
The paper presents a novel framework for scaling robotics simulation creation using coding agents, resulting in a high-fidelity benchmark (RoboWorld) that exposes the limitations of current frontier models. While the lack of sim-to-real transfer is a significant gap, the technical depth of the simulations and the innovative use of LLMs for simulation generation represent a substantial contribution to the field.
Methodology
The paper introduces "Gym-Anything for Robotics," a framework leveraging coding agents to automatically generate realistic robotics simulations. The core methodological innovation is the "adversarial creation-audit loop," where an agent creates a simulation and a separate verifier checks it against rigorous physical and task definitions. The paper demonstrates this by building "RoboWorld," a suite of 25 simulations covering economically valuable physical tasks (e.g., welding, sewing, fluid mixing, forklift operation). The simulations are notably detailed, incorporating specific physical laws (e.g., Hertz/Hunt-Crossley contact, Drucker-Prager powder mechanics, Bingham thin-film lubrication) and real-world object parameters (datasheet dimensions, material properties). The learning component explores several novel training strategies, including in-context learning across attempts, privileged teacher-student setups, and code policies for generating demonstrations for Vision-Language-Action (VLA) models.
Results & evaluation
The experimental evaluation is extensive in scope, covering 25 distinct simulation domains. The paper reports that even frontier models fail on the test tasks, achieving an average reward of only 0.06, which highlights the difficulty and realism of the benchmark. The authors demonstrate that their proposed learning methods (in-context learning, privileged teaching, code policies) substantially improve performance over baselines. The comparison table with prior simulations is detailed, showing that RoboWorld simulations include significantly more physics checks and adversarial evaluator cases than prior work. However, the evaluation is limited to simulation performance; there is no sim-to-real transfer evaluation, which is a critical gap for a robotics paper claiming to enable real-world training.
Reproducibility
The authors state that the pipeline, RL environments, and benchmark are released. The project URL is provided. The level of detail in the simulation descriptions (e.g., specific solver parameters, material properties, robot configurations) suggests high reproducibility for the simulation setup. However, the reliance on coding agents for generation introduces variability, and the exact prompts or agent configurations used to generate the 25 simulations are not fully detailed in the provided text, which may limit exact reproduction of the generation process.
Limitations
The primary limitation is the lack of sim-to-real validation. The paper argues that realistic simulations enable transfer, but does not demonstrate this. The benchmark is extremely difficult (average reward 0.06), which may be a barrier for adoption if the learning curves are not well-characterized. The reliance on coding agents for simulation creation may introduce subtle errors or biases that are not fully captured by the adversarial audit loop. The paper is also very long and complex, which may hinder accessibility.
Broader impact
This work has high potential impact by addressing a fundamental bottleneck in robotics research: the scalability of simulation creation. If the framework can be extended to generate thousands of high-fidelity simulations, it could enable large-scale pre-training of embodied AI models. The focus on economically valuable tasks (GDP-based selection) aligns with practical industrial applications. The release of the benchmark and pipeline will likely stimulate research in simulation-based RL and embodied AI. The paper presents a novel framework for scaling robotics simulation creation using coding agents, resulting in a high-fidelity benchmark (RoboWorld) that exposes the limitations of current frontier models. While the lack of sim-to-real transfer is a significant gap, the technical depth of the simulations and the innovative use of LLMs for simulation generation represent a substantial contribution to the field.
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