Robot Simulators: The Open, The Flashy, and The Nerdy

In the robot sim frontier of March 2025, it’s a three-way showdown (so far): Gazebo’s open vibes, Isaac SIM’s flashy flair, and MuJoCo’s nerdy grit. Picture a Leone stand-off, but with bots instead of six-shooters. Let's corral GitHub stars, FPS stats, and more to settle this dust-up.

What are we talking about?

Simulators are the proving grounds for robot wranglers, dodging real-world tumbleweeds. Gazebo’s been staking claims since 2002, Isaac SIM’s the new hotshot with NVIDIA’s Omniverse shine, and MuJoCo, unshackled by DeepMind in 2021-2022, is the research posse’s pick.

The shootout: which one is best?

Here’s the shootout: openness, speed, sensors, visuals, and fanbase, with a table to mark the territory.

Simulator	Open Source	GPU	Sensors	Physics Engine	Visual	Dynamics
Gazebo	✔	✘	RGBD, Lidar, Force, IMU	Bullet, ODE, DART, Simbody	Rasterizationonly	Rigid
MuJoco	✔	✔*	RGBD, Force, IMU, Tactile	Mujoco proprietary	Rasterization	Rigid, Soft, Cloth
Isaac SIM	✘	✔	RGBD, Lidar, Force, Effort, IMU, Contact, Proximity	PhysX 5	Rasterization RayTracing	Rigid

*GPU accel via MJX (Nvidia/AMD GPUs, Apple Silicon, Google TPUs)

Let's see how they do in terms of FPS

Simulator	RTX4090	A100
Gazebo	n/a	n/a
MuJoco RGB	2262.59	88.68
MuJoco Depth	1039.91	288.61
MuJoco Segmentation	320.86	119.74
Isaac SIM RGB	182.33	102.43
Isaac SIM Depth	156.31	92.43
Isaac SIM Segmentation	141.08	97.43

Gazebo: The Open

Gazebo’s the open-hearted trailblazer-free, tied to ROS, and packing physics engines like a mule train. Its sensor suite is ready for action, with 3949 citations and 1.1k GitHub stars as its bounty. But no GPU means it’s a dawdler, and its rasterized visuals are more wanted poster than a technicolour dream.

Isaac SIM: The Flashy

Isaac SIM’s the flashy guy from out of town, GPU-powered with NVIDIA’s shine, PhysX 5, and visuals that’d steal the spotlight; rasterization and ray tracing. Sensors? You name it: RGBD, Lidar, proximity. A slick all-in-one simulator, but it’s a hired hand (not open-source), and its adoption could be better; the price frightens many.

MuJoCo: The Nerdy

MuJoCo’s the nerdy maverick, open-sourced by DeepMind, with GPU accel via MJX tearing across Nvidia, AMD, Apple Silicon, and Google TPUs (MuJoCo). It’s a speed monster: 2262.59 FPS for RGB on an RTX 4090, 1039.91 for depth, 320.86 for segmentation. Wrangles rigid, soft, and cloth like a trick rider, but its sensor posse’s thin (no Lidar or proximity) and rasterized visuals keep it humble. Still, 4884 citations and 6.6k GitHub stars make it a legend.

Who is the winner?

Well as an engineer, my answer is: it depends. Everyone has pros and cons, and you can choose any of these as your sidekick for your next project without regrets.

Your requirements and scope will drive the decision.

The new age of robotics and AI is moving fast, and the lack of GPU acceleration seems a big miss for Gazebo, which may represent the beginning of its downfall when options like MuJoco are available.

However, MuJoco has not already won. Sim to real in simulation is a big topic, and Isaac Sim can handle very close to real simulation, which offers more representative data for training that suffers less of these problems.

With more people embracing this software, prices might go down and new features might be integrated, making these stand-offs even more difficult.

As roboticists, we should look with great interest at this evolution and re-evaluate the best tool for us at any time!

#AI #Robotics #simulator #Mujoco #IsaacSim #Nvidia #Mujoco #Deepmind