Environment Configuration — Parallelism

One of Space Robotics Bench’s most powerful features is parallel simulation, allowing you to run multiple simulation instances simultaneously. This capability is critical for:

Reinforcement Learning: Collect experience at scale for faster training
Parameter Tuning: Test multiple configurations simultaneously
Monte Carlo Sampling: Evaluate robustness across varied scenarios
Batch Processing: Process multiple scenarios in a single run

Number of Environments

The env.scene.num_envs parameter controls how many parallel simulation instances are created. This parameter is aliased as env.num_envs for brevity:

srb agent rand -e _manipulation env.scene.num_envs=16
srb agent zero -e _manipulation env.num_envs=128

Each environment is a fully independent physics simulation instance, with all cross-environment interactions disabled (filtered collisions). However, there is only one instance of the rendering engine, which means that a visual sensor in one environment will see entities from all environments. A simple workaround for this limitation is to increase the spacing between environments and clip the maximum sensor range.

Environment Spacing

The env.scene.env_spacing parameter controls the spatial distance between environments. This parameter is aliased as env.spacing for brevity:

srb agent rand -e _manipulation env.num_envs=64 env.scene.env_spacing=20.0
srb agent rand -e _manipulation env.num_envs=32 env.spacing=10.0

Note: When env.stack=true, the framework forces env.scene.env_spacing=0.0 regardless of the value of env.spacing, since stacked environments share the same scenery position.

Environment Stacking

The env.stack parameter controls whether environments share assets or have independent assets:

Independent Environments (`env.stack=false`)

⚠️ Each environment has a unique scene and position
✅ Greater visual and physical diversity
✅ Supports tasks with visual sensors
❗ Slower to initialize
❗ Higher memory usage

srb agent rand -e _manipulation env.num_envs=16 env.stack=false

Stacked Environments (`env.stack=true`)

⚠️ All environments share the same scenery and position
✅ Faster to initialize
✅ Lower memory usage
❗ Less environmental diversity
❗ Does not support tasks with visual sensors
❗ Does not support particle or cloth simulation with multiple environments — when env.particles=true or env.cloth=true and env.num_envs != 1, the framework forces env.stack=false (a warning is logged)

srb agent rand -e _manipulation env.num_envs=16 env.stack=true

Note: The default is task-specific. Non-visual locomotion_velocity_tracking and the single-env public excavation_demo default to env.stack=true.

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