Headless Mode

Running a simulator with no graphical window open, commonly used for batch training and data collection on a server.

Headless means running a program without a graphical user interface (GUI). In embodied AI, this mainly means running simulators such as Isaac Sim/Isaac Lab or MuJoCo on a GPU server with no monitor attached: no window pops up and nothing is displayed in real time, which saves overhead and speeds up training and data generation. Isaac Lab scripts just need a --headless flag added, which its documentation describes as launching “without a graphical interface”; if the environment has cameras that need to output images, --enable_cameras also needs to be added to enable off-screen rendering. Tools in the MuJoCo family use the environment variable MUJOCO_GL=egl for windowless rendering on the GPU, while osmesa does pure CPU software rendering. Note that headless doesn't mean no rendering at all — it just means nothing is displayed; to view the output remotely, Isaac Lab's livestream feature or video recording can be used instead.

ExampleRunning python scripts/reinforcement_learning/rsl_rl/train.py --task=Isaac-Cartpole-v0 --headless on a server trains a cart-pole policy with no window opened.

Also called

--headless, Headless Rendering

Related

NVIDIA Isaac Lab · NVIDIA Isaac Sim · MuJoCo (Multi-Joint dynamics with Contact) · Batched Rendering · GPU-Accelerated Parallel Simulation · Simulation Throughput (Steps / Frames Per Second)

Sources

Isaac Lab API: isaaclab.app (AppLauncher)
google-deepmind/dm_control README: Rendering

As of

2026-09