Optimize Stage Creation

Optimize Stage Creation#

Isaac Lab supports two experimental features to speed-up stage creation: fabric cloning and stage in memory. These features are particularly effective for large-scale RL setups with thousands of environments.

What These Features Do#

Fabric Cloning

Clones environments using Fabric library (see USD Fabric USDRT Documentation)
Partially supported and enabled by default on some environments (see Limitations section for a list)

Stage in Memory

Constructs the stage in memory, rather than with a USD file, avoiding overhead from disk I/O
After stage creation, if rendering is required, the stage is attached to the USD context, returning to the default stage configuration
Not enabled by default

Usage Examples#

Fabric cloning can be toggled by setting the isaaclab.scene.InteractiveSceneCfg.clone_in_fabric flag. For a full guide on the template-based cloning system, see Cloning Environments.

Using Fabric Cloning with a RL environment

# create environment configuration
env_cfg = CartpoleEnvCfg()
env_cfg.scene.clone_in_fabric = True
# setup RL environment
env = ManagerBasedRLEnv(cfg=env_cfg)

Stage in memory can be toggled by setting the isaaclab.sim.SimulationCfg.create_stage_in_memory flag.

Using Stage in Memory with a RL environment

# create config and set flag
cfg = CartpoleEnvCfg()
cfg.scene.num_envs = 1024
cfg.sim.create_stage_in_memory = True
# create env with stage in memory
env = ManagerBasedRLEnv(cfg=cfg)

When using stage in memory without an existing RL environment class, wrap the stage creation steps in a with statement to set the stage context. The stage is automatically attached to the USD context when SimulationContext is created with create_stage_in_memory=True.

Using Stage in Memory with a manual scene setup

# init simulation context with stage in memory
# Note: stage is automatically attached to USD context
sim = SimulationContext(cfg=SimulationCfg(create_stage_in_memory=True))

# grab stage and set stage context
with stage_utils.use_stage(sim.stage):
    # create cartpole scene
    scene_cfg = CartpoleSceneCfg(num_envs=1024)
    scene = InteractiveScene(scene_cfg)

sim.play()

Limitations#