Asset Preview

Asset Preview#

The preview_asset script loads a USD or mesh asset into the simulation for visual inspection and debugging, without requiring a full gym environment. It supports both rigid objects (meshes) and articulations (robot-like assets), with an optional interactive session for manipulation.

Quick Start#

Preview a rigid object from a USD file:

python -m embodichain.lab.scripts.preview_asset \
    --asset_path /path/to/sugar_box.usda \
    --asset_type rigid

Preview an articulation:

python -m embodichain.lab.scripts.preview_asset \
    --asset_path /path/to/robot.usd \
    --asset_type articulation

Asset Type Detection#

The asset type is determined as follows:

  1. Explicit: use --asset_type rigid or --asset_type articulation.

  2. URDF files: automatically treated as articulations.

  3. USD files: the USD stage is inspected for UsdPhysicsArticulationRoot prims. If found, the file is loaded as an articulation; otherwise as a rigid object.

  4. Other mesh formats (.obj, .stl, .glb, etc.): always loaded as rigid objects.

Interactive Preview Mode#

Pass --preview to enter an interactive REPL after the asset is loaded:

python -m embodichain.lab.scripts.preview_asset \
    --asset_path /path/to/robot.usd \
    --asset_type articulation \
    --preview

Available commands inside the REPL:

Command

Description

p

Enter an IPython embed session. sim and asset are in scope.

s <N>

Step the simulation N times (default 10).

q

Quit the simulation.

Inside the IPython embed session you can freely inspect and manipulate the asset:

# Inspect articulation joint positions
asset.get_qpos()

# Step the simulation
sim.update(step=10)

# Change asset position
asset.set_root_pose(pos=[0, 0, 1.0], rot=[0, 0, 0])

Command-Line Arguments#

Argument

Description

Default

--asset_path

Path to the asset file (.usd/.usda/.usdc/.obj/.stl/.glb/.urdf)

required

--asset_type

Type of asset: rigid or articulation

Auto-detected (fallback: rigid)

--uid

Unique identifier in the scene

Derived from filename

--init_pos

Initial position as x y z

0 0 0.5

--init_rot

Initial rotation in degrees as rx ry rz

0 0 0

--body_type

Body type for rigid objects: dynamic, kinematic, static

kinematic

--use_usd_properties

Use physical properties from the USD file instead of defaults

False

--fix_base

Fix the base of articulations

True

--sim_device

Simulation device

cpu

--headless

Run without rendering window

False

--enable_rt

Enable ray tracing

False

--preview

Enter interactive embed mode after loading

False

Examples#

Headless smoke test (no render window):

python -m embodichain.lab.scripts.preview_asset \
    --asset_path /path/to/asset.usda \
    --headless

Custom position and rotation:

python -m embodichain.lab.scripts.preview_asset \
    --asset_path /path/to/robot.usd \
    --asset_type articulation \
    --init_pos 0.5 0 0.0 \
    --init_rot 0 0 90 \
    --preview

Dynamic rigid body (falls under gravity):

python -m embodichain.lab.scripts.preview_asset \
    --asset_path /path/to/box.obj \
    --body_type dynamic \
    --preview
Contents