Building Virtual Cities for Smarter Robots

Author: Denis Avetisyan


Researchers have created a highly realistic urban simulator designed to accelerate progress in robot navigation, collaboration, and understanding of the world around them.

SimWorld Robotics establishes a scalable simulation platform-built upon Unreal Engine 5-for the development of embodied agents operating within photorealistic urban environments, leveraging procedural generation and a city-scale waypoint-driven traffic system to facilitate testing in dynamic, large-scale scenarios.
SimWorld Robotics establishes a scalable simulation platform-built upon Unreal Engine 5-for the development of embodied agents operating within photorealistic urban environments, leveraging procedural generation and a city-scale waypoint-driven traffic system to facilitate testing in dynamic, large-scale scenarios.

SimWorld-Robotics offers a new benchmark for embodied AI, featuring photorealistic environments and challenges for multi-robot systems and vision-language models.

Despite recent advances in embodied AI, generalizing robotic capabilities to complex, real-world urban environments remains a significant challenge. This paper introduces SimWorld-Robotics: Synthesizing Photorealistic and Dynamic Urban Environments for Multimodal Robot Navigation and Collaboration, a novel high-fidelity simulation platform coupled with challenging benchmarks for multi-robot collaboration and vision-language navigation. Our results reveal that current state-of-the-art models struggle with tasks requiring robust perception, reasoning, and planning in these dynamic settings. Can these new benchmarks accelerate the development of truly versatile and adaptable robots capable of navigating and collaborating in our increasingly complex urban landscapes?


The Persistent Discrepancy Between Simulation and Reality

The efficacy of embodied artificial intelligence hinges on its ability to translate skills learned in simulation to the complexities of the physical world, but current simulators frequently fall short of providing a sufficiently realistic training ground. Often, these virtual environments are limited in scale – both in terms of spatial extent and the diversity of objects and agents – and lack the fidelity needed to accurately model real-world physics, sensor noise, and material properties. This discrepancy between simulation and reality creates a significant generalization gap, where agents trained in simplified environments struggle to perform reliably when deployed in real-world scenarios. Consequently, improvements in simulated performance do not always translate to gains in real-world robotic capabilities, highlighting the urgent need for more expansive and physically plausible embodied AI simulators to unlock the full potential of intelligent robotics.

Current embodied AI simulators frequently exhibit a narrow focus, often excelling in replicating a single modality like autonomous driving or robotic manipulation, but falling short when tasked with broader, more integrated challenges. This specialization limits the development of truly versatile agents; a robot proficient in a simulated driving environment may struggle to adapt to a home setting requiring navigation, object recognition, and human interaction. Crucially, many platforms lack the dynamic, interactive elements inherent in real-world environments, offering static scenes or pre-scripted events rather than responsive, unpredictable scenarios. This absence of genuine interactivity hinders an agent’s ability to learn robust strategies for dealing with novelty and unforeseen circumstances, creating a significant gap between simulated performance and real-world applicability.

The development of truly adaptable and intelligent robots is currently constrained by a significant bottleneck: the inability to reliably train and assess agents within sufficiently complex virtual environments. Current simulation technologies often fail to capture the nuances of real-world physics, sensorimotor interactions, and unpredictable events, leading to agents that perform well in controlled simulations but falter when deployed in unstructured, dynamic settings. This discrepancy hinders progress not only in robot design but also in the evaluation of AI algorithms, as performance within a simplified environment does not reliably translate to robust, real-world capabilities. Consequently, researchers face ongoing challenges in bridging the “reality gap” and creating agents capable of genuine navigation and interaction with the complexities of everyday life, necessitating advancements in both simulation fidelity and training methodologies.

The development of truly intelligent embodied agents is increasingly constrained by the difficulty of crafting simulation environments that strike a delicate balance between computational cost and representational fidelity. While highly detailed, photorealistic simulations offer potentially valuable training data, they often demand prohibitive processing power, limiting both the scale and duration of agent learning. Conversely, simplified environments, though computationally efficient, may lack the nuanced complexity necessary for an agent to develop robust generalization capabilities when deployed in the real world. This presents a significant challenge: researchers strive to create virtual worlds that are rich enough to foster meaningful AI progress-allowing agents to learn diverse skills and adapt to unforeseen circumstances-yet simultaneously tractable enough to enable large-scale experimentation and iteration. Bridging this gap requires innovative approaches to environment design, potentially involving procedural generation, efficient rendering techniques, and strategic abstraction of irrelevant details, ultimately unlocking the full potential of simulation-based robot learning.

Our simulator surpasses existing platforms like MetaUrban, MetaDrive, AirSim, and CARLA by combining realistic environmental effects, diverse high-fidelity buildings, and nuanced pedestrian behaviors that accurately reflect complex urban dynamics.
Our simulator surpasses existing platforms like MetaUrban, MetaDrive, AirSim, and CARLA by combining realistic environmental effects, diverse high-fidelity buildings, and nuanced pedestrian behaviors that accurately reflect complex urban dynamics.

SimWorld-Robotics: A Platform for Rigorous Embodied AI Research

SimWorld-Robotics is a novel platform for embodied AI research and development, constructed using the Unreal Engine 5 framework. This allows for the creation of highly detailed and visually realistic urban simulations. The platform is specifically engineered to support large-scale environments, facilitating the training and testing of AI agents in complex scenarios. Environments are not pre-defined but are dynamically generated, allowing for diverse and varied testing conditions. The use of Unreal Engine 5 also enables the incorporation of advanced rendering techniques, including ray tracing and global illumination, to improve the fidelity of the simulation and create more realistic sensor data for AI agents.

SimWorld-Robotics utilizes procedural city generation techniques to construct simulated environments, enabling the rapid creation of large-scale, varied urban landscapes. Each generated environment averages 2 km² in area, providing substantial space for agent operation and data collection. This procedural approach allows for the automated creation of diverse layouts, building types, and road networks, significantly reducing the manual effort required for environment design. The platform’s capacity to generate expansive environments at scale is critical for evaluating AI agents in complex, realistic scenarios and supports the simulation of a wide range of operational conditions.

SimWorld-Robotics incorporates multiple navigation strategies to facilitate agent movement and task completion within simulated environments. These strategies include, but are not limited to, waypoint navigation, which allows users to define a series of discrete points for agents to traverse. This method enables precise control over agent paths and supports complex task execution requiring sequential actions at specific locations. The platform’s support for diverse navigational approaches is designed to accommodate varied agent behaviors and enable testing in scenarios requiring differing levels of autonomy and precision. Further strategies are implemented to manage obstacle avoidance, dynamic replanning, and adaptation to changing environmental conditions.

SimWorld-Robotics addresses the limitations of current AI training methodologies by focusing on high-fidelity simulation and environmental complexity. The platform’s large-scale, photorealistic environments – averaging 2 km² in area – and support for diverse navigation strategies are intended to expose AI agents to a wider range of scenarios than typically encountered in simpler simulations. This increased realism and variability are crucial for developing agents that can generalize effectively to real-world conditions, mitigating the performance drop often observed when deploying AI trained solely in limited or unrealistic environments. The ultimate goal is to create AI systems exhibiting greater robustness and adaptability across a spectrum of operational contexts.

Scene World Representation (SWR) modularizes procedural city generation from user specifications into distinct elements-roads, buildings, details, and traffic.
Scene World Representation (SWR) modularizes procedural city generation from user specifications into distinct elements-roads, buildings, details, and traffic.

Establishing Standardized Benchmarks: SimWorld-MMNav and SimWorld-MRS

SimWorld-MMNav and SimWorld-MRS are newly developed benchmarks designed for evaluating AI agents in robotic navigation and multi-robot search scenarios. Both benchmarks are implemented within the SimWorld-Robotics simulation platform, providing a controlled and scalable environment for experimentation. SimWorld-MMNav focuses on multimodal robot navigation, requiring agents to interpret both visual and linguistic instructions to reach specified goals. SimWorld-MRS assesses the performance of multiple robots collaborating to locate targets within a defined space, emphasizing coordination and efficiency. These benchmarks are intended to facilitate standardized evaluation and comparison of various AI methodologies, including Vision-Language Models and pathfinding algorithms, in complex, dynamic environments.

SimWorld-MMNav and SimWorld-MRS leverage Vision-Language Models (VLMs) to interpret natural language instructions and translate them into actionable robotic behaviors. These VLMs are integrated with established pathfinding algorithms, specifically A, to enable agents to navigate and complete tasks within the simulated environments. The A algorithm facilitates the computation of optimal paths, while the VLM provides the perceptual and linguistic understanding necessary to interpret goals and avoid obstacles. Agent performance is then evaluated based on its ability to successfully execute instructions in complex, dynamic scenarios, requiring both accurate perception and effective planning.

Dataset SimWorld-20k comprises 20,000 sequential steps generated within the SimWorld-Robotics environment and is fundamental to the training and evaluation of Vision-Language Models (VLMs) used in the SimWorld-MMNav and SimWorld-MRS benchmarks. This dataset provides the necessary scale for supervised learning and reinforcement learning approaches, allowing for robust assessment of agent performance in complex navigation and search tasks. The dataset’s size facilitates the development of models capable of generalizing to unseen scenarios and accurately interpreting multimodal inputs – specifically, visual observations and natural language instructions – within dynamic environments. Without a large-scale dataset like SimWorld-20k, training effective VLMs for embodied AI remains significantly limited.

SimWorld-MMNav and SimWorld-MRS provide a controlled, standardized environment for evaluating and comparing AI algorithms designed for robot navigation and multi-robot coordination. Performance is assessed through a rigorous set of tasks within these simulated environments, allowing for quantitative tracking of progress in embodied AI. Initial results demonstrate that a finetuned QwenVL2.5-7B model achieves a measurable, non-zero success rate on these benchmarks, indicating improved performance relative to baseline models that previously exhibited limited capabilities within the SimWorld-Robotics platform.

This image illustrates a robot navigating using multiple modalities to complete a task.
This image illustrates a robot navigating using multiple modalities to complete a task.

Expanding the Horizons of Embodied AI: A Consolidated Approach

SimWorld-Robotics represents a significant advancement in embodied artificial intelligence research by building upon and integrating the strengths of established simulation platforms – including VirtualHome, RoboTHOR, TDW, Virtual Community, and BEHAVIOR. Rather than replacing these tools, it functions as a unifying layer, offering a more comprehensive and scalable environment for training and evaluating AI agents. This consolidated approach addresses limitations inherent in individual simulators, such as restricted environment complexity or limited scalability, and enables researchers to create and test agents in increasingly realistic and challenging scenarios. The platform’s design prioritizes the ability to handle a wider range of tasks and environments, fostering the development of more robust and adaptable AI systems capable of generalizing to the complexities of the real world.

SimWorld-Robotics addresses a critical need within embodied AI research: a standardized platform for both training artificial intelligence agents and rigorously evaluating their performance. Previously, fragmented simulator landscapes required researchers to adapt algorithms to multiple environments, hindering direct comparison and collaborative advancement. This new environment unifies the training and evaluation processes, enabling researchers to share models, datasets, and benchmarks more effectively. Consequently, progress is accelerated as insights gained within SimWorld-Robotics are more readily transferable and verifiable across the broader community, fostering a more iterative and impactful cycle of innovation in the development of intelligent, embodied agents.

SimWorld-Robotics distinguishes itself through environments designed to mimic the complexities of the physical world, going beyond static scenes to incorporate dynamic elements and unpredictable events. This realism is crucial for training artificial agents to perform tasks requiring robust perception, planning, and adaptation-skills essential for real-world applications. The platform allows for the development of agents proficient in complex navigation through cluttered spaces, efficient search for specific objects amidst distractions, and nuanced interaction with both objects and potentially other agents. By exposing agents to a continuous stream of changing conditions, SimWorld-Robotics fosters the creation of AI systems capable of generalizing learned behaviors to novel situations, ultimately bridging the gap between simulated performance and success in authentic, unstructured environments.

The development of SimWorld-Robotics represents a significant stride towards unlocking new possibilities within embodied artificial intelligence. By consolidating diverse simulation environments into a single, cohesive platform, the approach actively dismantles traditional research barriers and encourages a more fluid exchange of ideas and methodologies. This unification isn’t merely logistical; it fosters a synergistic environment where researchers can readily build upon each other’s work, accelerating the pace of discovery and allowing for more complex and ambitious projects. Consequently, the platform isn’t just a tool for training agents, but a catalyst for fundamentally reshaping the landscape of embodied AI, enabling investigations into increasingly sophisticated behaviors and ultimately, the creation of agents capable of navigating and interacting with the physical world with greater autonomy and intelligence.

The robot utilizes RGB, segmentation, and depth data to navigate and manipulate objects within its environment, employing a discrete action space encompassing translation, rotation, idling, and viewpoint control.
The robot utilizes RGB, segmentation, and depth data to navigate and manipulate objects within its environment, employing a discrete action space encompassing translation, rotation, idling, and viewpoint control.

The creation of SimWorld-Robotics exemplifies a dedication to provable systems, mirroring a core tenet of computational rigor. This simulator isn’t simply designed to appear realistic; its high-fidelity rendering and dynamic environments are built upon a foundation intended to support verifiable AI behavior. As Grace Hopper once stated, “It’s easier to ask forgiveness than it is to get permission.” This sentiment, while often applied to innovation, holds true for simulation as well – pushing the boundaries of what’s possible necessitates a willingness to build and refine, even if complete validation isn’t immediately attainable. SimWorld-Robotics, by offering a robust benchmark for multi-robot collaboration, demands algorithms that are demonstrably correct, not merely functional, thereby aligning with the pursuit of mathematical purity in code.

What Remains Constant?

The creation of SimWorld-Robotics represents a predictable escalation in the fidelity of simulated environments. Yet, let N approach infinity – what remains invariant? The core challenge isn’t rendering photorealistic textures or dynamic occlusion; it’s the fundamentally brittle nature of translating perceptual data into robust, generalizable action. The benchmark, however impressive, measures performance within the simulation. The true metric will be transferability – the degree to which algorithms honed in this digital city function, without catastrophic failure, in the profoundly messier reality.

Current vision-language models, while exhibiting superficial competence, still grapple with ambiguity and unexpected events. SimWorld-Robotics, with its controlled complexity, risks becoming a local maximum – a proving ground for increasingly elaborate heuristics that mask, rather than solve, the underlying problems of perception and reasoning. The pursuit of ‘realistic’ simulation should not overshadow the need for algorithms grounded in mathematical certainty, capable of operating even when faced with sensor noise or unforeseen circumstances.

Future work must prioritize the development of algorithms that exhibit provable robustness, rather than merely empirical success. The focus should shift from creating ever-more-detailed simulations to designing formal verification methods that can guarantee the safety and reliability of robotic systems operating in the real world. Only then will the promise of embodied AI truly be realized.


Original article: https://arxiv.org/pdf/2512.10046.pdf

Contact the author: https://www.linkedin.com/in/avetisyan/

See also:

2025-12-12 09:14