Implementation:Haosulab ManiSkill SapienUtils

Knowledge Sources	Haosulab_ManiSkill
Domains	Robotics, Simulation, SAPIEN
Last Updated	2026-02-15 08:00 GMT

Overview

Concrete tool for SAPIEN-specific utility functions including object lookup, URDF configuration validation, camera setup, and pose/tensor operations.

Description

The sapien_utils.py module provides utility functions that interface directly with the SAPIEN simulation engine. These utilities are used extensively across ManiSkill for object management, configuration, and rendering setup.

Object Lookup:

• get_obj_by_name() -- Find a SAPIEN object (Entity, Link, etc.) by name from a list, optionally enforcing uniqueness.
• get_objs_by_names() -- Find multiple objects by a list of names, returning them in the requested order.
• get_obj_by_type() -- Find objects by their Python type.

Configuration Validation:

• check_urdf_config() -- Validate URDF loader configuration dictionaries against allowed keys (material, density, link).
• apply_urdf_config() -- Apply a URDF config dict to a URDFLoader, setting material properties (static/dynamic friction, restitution, density) and per-link overrides.

Camera Utilities:

• set_shader_pack() -- Set the global shader pack for the SAPIEN render system.
• Camera model matrix computation from mount pose and local pose.

Pose and Tensor Operations:

• to_tensor() / to_numpy() -- Wrappers for device-aware data conversion.
• compute_total_pose() -- Compute world-frame poses from entity chain.

Usage

Import from mani_skill.utils.sapien_utils when you need to interact with SAPIEN objects directly, look up entities by name, or configure URDF loading parameters.

Code Reference

Source Location

• Repository: Haosulab_ManiSkill
• File: mani_skill/utils/sapien_utils.py

Signature

def get_obj_by_name(objs: list[T], name: str, is_unique=True) -> T: ...
def get_objs_by_names(objs: list[T], names: list[str]) -> list[T]: ...
def get_obj_by_type(objs: list[T], target_type: T, is_unique=True) -> T: ...
def check_urdf_config(urdf_config: dict) -> None: ...
def apply_urdf_config(loader: URDFLoader, urdf_config: dict) -> None: ...

Import

from mani_skill.utils import sapien_utils
# or
from mani_skill.utils.sapien_utils import get_obj_by_name, check_urdf_config

I/O Contract

Inputs

Name	Type	Required	Description
objs	list[T]	Yes	List of SAPIEN objects to search (entities, links, etc.)
name	str	Yes	Name to search for
is_unique	bool	No	Whether name must be unique (default True)
urdf_config	dict	Yes	URDF loader configuration dictionary

Outputs

Name	Type	Description
return	T or None	Matched SAPIEN object, or None if not found
return	list[T]	List of matched objects (for get_objs_by_names)

Usage Examples

Basic Usage

from mani_skill.utils.sapien_utils import get_obj_by_name

# Find an actor by name in a scene
actor = get_obj_by_name(scene.get_all_actors(), "target_cube")

# Find a link by name in an articulation
link = get_obj_by_name(articulation.get_links(), "gripper_link")

Related Pages

• Environment:Haosulab_ManiSkill_Python_SAPIEN_Core
• Haosulab_ManiSkill_URDFLoader
• Haosulab_ManiSkill_Actor