In progress We are upgrading REALM to v1.0.0 β€” running on Isaac Sim 5.1 and OmniGibson 3.9.1, with major speedups, parallelization, full documentation, and a revised leaderboard.
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A real-to-sim validated benchmark for generalization in robotic manipulation

High-fidelity simulation with aligned robot control β€” 15 perturbation factors, 7 manipulation skills, 4,000+ objects β€” that predicts how VLA policies behave in the real world.

1 Czech Institute of Informatics, Robotics and Cybernetics, CTU in Prague 2 Faculty of Electrical Engineering, CTU in Prague 3 University of Amsterdam
Accepted to IEEE RA-L Β· To be presented at IROS 2026

Teaser video

Overview of the environment
Overview

A simulation benchmark whose numbers track the real robot

REALM is a large-scale realistic simulation environment and benchmark for generalization in robotic manipulation. It supports 7 distinct manipulation skills and stress-tests them against 15 perturbations. Through empirical validation, we show that evaluation results in simulation are strongly correlated with real-world performance. Setup instructions, task definitions and the evaluation API are documented in the repository wiki.

15perturbation factors
7manipulation skills
4,000+objects
3VLA models evaluated
REALM overview figure
Abstract

Evaluating Ο€0, Ο€0-FAST and GR00T N1.5 under systematic perturbation.

Vision-Language-Action (VLA) models empower robots to understand and execute tasks described by natural language instructions. However, a key challenge lies in their ability to generalize beyond the specific environments and conditions they were trained on, which is presently difficult and expensive to evaluate in the real world. To address this gap, we present REALM, a new simulation environment and benchmark designed to evaluate the generalization capabilities of VLA models, with a specific emphasis on establishing a strong correlation between simulated and real-world performance through high-fidelity visuals and aligned robot control. Our environment offers a suite of 15 perturbation factors, 7 manipulation skills, and more than 4,000 objects. Finally, we establish two task sets that form our benchmark and evaluate the Ο€0, Ο€0-FAST, and GR00T N1.5 VLA models, showing that generalization and robustness remain an open challenge. More broadly, we also show that simulation gives us a valuable proxy for the real world and allows us to systematically probe for and quantify the weaknesses and failure modes of VLAs.

Takeaways

Six findings from evaluating VLAs under perturbation

I

High-fidelity simulation with aligned robot control can serve as a valuable proxy for real-world performance, mitigating the issue of saturated simulation benchmarks.

II

Despite VLM backbones pretrained on Internet-scale data, there is a noticeable drop in performance from purely semantic perturbations.

III

There is still a noticeable sensitivity to camera view for all models, despite the unusually high diversity of viewpoints in the DROID dataset.

IV

Behavioral generalization across objects and their properties is the most challenging for all tested models.

V

Conversely, all tested models seem to generalize well across known skills when the manipulated object remains the same.

VI

Reliability and robustness under perturbations is still highly challenging β€” models exhibit very low success rates on many basic manipulation tasks.

While we recognize the tremendous progress that enabled VLAs to start performing manipulation tasks in unseen settings, including many scenes in our simulation, we believe these results indicate that current models still lack the capabilities for autonomous real-world deployment.

Rollouts

Example policy evaluations

Perturbations

Fifteen ways to break a policy

To assess the robustness of VLAs under variable conditions, we implemented perturbations that change the visual, behavioral, and semantic properties of the tasks and environments. We adopt 14 of the 22 perturbations from the β˜†-Gen taxonomy and introduce a separate 15th V-LIGHT perturbation for scene illumination.

Visualizer

Hover a segment to see how the scene changes.

β€œPick up the spoon.”
Default
Visual
Semantic
Behavioral
Visual+Behav.
Sem.+Behav.
Vis+Sem+Behav.
Descriptions of the 15 perturbations
Description of the perturbations used in our approach.
Real-to-Sim Validation

Does simulation help us predict real performance?

Real-to-sim correlation figure
Sim-to-real validation of REALM. Task progression is shown in the real world (x-axis) and simulation (y-axis). Left: a strong Pearson correlation (r) with datapoints close to identity (gray dashed line) and a low Mean Maximum Rank Violation (MMRV) on 7 tasks under 5 visual and behavioral perturbations. Right: results are also highly correlated under individual perturbations. We observe p < 0.001 between real and simulated rollouts for all settings, indicating that REALM is a strong proxy for real-world performance.
Trajectory following comparison
Control alignment. A trajectory replay in simulation with default robot control (left) and our aligned control (right). Yellow is ground truth from a real robot, blue is simulation β€” alignment yields significantly more realistic trajectory following.
Attention maps from the pi0 action expert
Attention maps from the Ο€0 action expert. Replaying the same trajectory in reality (top) and simulation (bottom), the model attends to similar patches β€” cosine similarity of 0.85/1 averaged over ~280 frames, all layers and heads.
Benchmark Results

Three VLAs, fifteen perturbations, eight tasks

A detailed evaluation of Ο€0, Ο€0-FAST and GR00T N1.5 under 15 distinct perturbations on the 8 tasks that comprise the REALM-base task set.

Overall results
Results on 8 tasks in the REALM-base task set, spanning 5 basic manipulation skills.
Success rate violin plots
Success rate (y-axis) on the REALM-base task set (x-axis). Violin plots show Bayesian posteriors of success rates under a uniform Beta prior and the observed data.
Time to completion
Time to completion. Average time to successfully complete each task per model, obtained by dividing simulation timesteps by the fixed control frequency β€” model inference time and latency are not accounted for.

Individual task results

Evaluation of three VLA models under 15 perturbations across the REALM-base and REALM-articulated task sets. Left: a visualization of the task. Right: task progression on the nominal default setting (black) and under individual perturbations (colored curves).

Instruction
Task visualization
Task visualization
Results under perturbations
Results under perturbations
πŸ†Leaderboard
Coming soon

A public ranking of the latest VLA models on REALM-base and REALM-articulated

We are extending the evaluation beyond Ο€0, Ο€0-FAST and GR00T N1.5 to the current generation of open VLA policies, and will publish the full per-perturbation breakdown as a continuously updated leaderboard. Submissions of your own policy will be open alongside it.

#ModelDefault SRPerturbed SRRobustness Ξ”
1To be announced
2To be announced
3To be announced
4To be announced
5To be announced

Results are being collected now β€” rankings publish with the camera-ready release.

Watch the repo for updates
Citation

BibTeX

@article{sedlacek2025realm,
    title={REALM: A Real-to-Sim Validated Benchmark for Generalization in Robotic Manipulation},
    author={Martin Sedlacek and Pavlo Yefanov and Georgy Ponimatkin and Jai Bardhan and
            Simon Pilc and Mederic Fourmy and Evangelos Kazakos and Cees G. M. Snoek and
            Josef Sivic and Vladimir Petrik},
    journal={arXiv preprint arXiv:2512.19562},
    year={2025}
}