API#

Python API#

`RobotAssembler`	RobotAssembler is a class to assemble robots from a base robot and an attachment robot.
`AssembledRobot`	A wrapper class providing convenient access to assembled robot body information.
`AssembledBodies`	Class representing two assembled rigid bodies connected by a fixed joint.

class RobotAssembler#

Bases: object

RobotAssembler is a class to assemble robots from a base robot and an attachment robot. It will create a new USD stage with the assembly and configure a variant selection to enable the attachment robot to be selected. If the variant set already exists in the source asset, it creates a new entry to it, otherwise it creates a new variant set.

Initialize the RobotAssembler

Parameters:: None
Returns:: None

assemble()#: Composes the attachment robot onto the base robot, so that the attachment robot is a child of the base robot, and ready to simulate.

assemble_rigid_bodies( base_path: str, attach_path: str, base_mount_frame: str, attach_mount_frame: str, mask_all_collisions: bool = True, refresh_asset_paths: bool = False, ) → AssembledBodies#

Assemble two rigid bodies into one physical structure

Parameters:

base_path – Path to base robot.
attach_path – Path to attach robot. The attach robot will be unrooted from the stage and attached only to the base robot.
base_mount_frame – Relative path to frame in base robot where there is the desired attach point.
attach_mount_frame – Relative path to frame in the attach robot where there is the desired attach point.
mask_all_collisions – Mask all collisions between attach robot and base robot. This is necessary when setting single_robot=False to prevent Physics constraint violations from the new fixed joint. Advanced users may set this flag to False and use the mask_collisions() function separately for more customizable behavior.
refresh_asset_paths – Whether to refresh asset paths after assembly.

Returns:

An object representing the assembled bodies. This object can detach the composed robots and edit the fixed joint transform.

begin_assembly( stage, base_prim_path, base_mount_path, attachment_prim_path, attachment_mount_path, variant_set, variant_name, )#

Start the robot assembly process.

Places the attachment robot relative to the base robot but does not compose them yet.

Parameters:

stage – USD stage for assembly
base_prim_path – Path to base robot prim
base_mount_path – Path to mount frame on base robot
attachment_prim_path – Path to attachment robot prim
attachment_mount_path – Path to mount frame on attachment robot
variant_set – Name of variant set to create/modify
variant_name – Name of variant to create

cancel_assembly()#: Cancel the current assembly operation and reset state.

create_fixed_joint( prim_path: str, target0: str = None, target1: str = None, ) → pxr.UsdPhysics.FixedJoint#

Create a fixed joint between two bodies

Parameters:

prim_path – Prim path at which to place new fixed joint.
target0 – Prim path of frame at which to attach fixed joint.
target1 – Prim path of frame at which to attach fixed joint.

Returns:

A USD fixed joint

finish_assemble()#: Finalize the assembly process by configuring variant sets and saving the assembly to a USD file.

get_articulation_root_api_path(prim_path: str) → str#

Get the prim path that has the Articulation Root API applied.

Parameters:: prim_path – Path to a prim
Returns:: Path to the prim that has the Articulation Root API applied

is_root_joint(prim) → bool#

Check if a prim is a root joint (has no body0 or body1 target).

Parameters:: prim – Prim to check
Returns:: True if prim is a root joint, False otherwise

mask_collisions( prim_path_a: str, prim_path_b: str, ) → pxr.Usd.Relationship#

Mask collisions between two prims. All nested prims will also be included.

Parameters:

prim_path_a – Path to a prim
prim_path_b – Path to a prim

Returns:

A relationship filtering collisions between prim_path_a and prim_path_b

reset()#: Reset the assembler to its initial state and cancel any active assembly operations.

class AssembledRobot( assembled_robots: AssembledBodies, )#

Bases: object

A wrapper class providing convenient access to assembled robot body information.

This class serves as a high-level interface for interacting with assembled robots, encapsulating the underlying AssembledBodies instance and exposing its key properties through a simplified API. It provides direct access to robot paths, joint information, and collision masking relationships for assembled robot configurations.

The class acts as a facade over AssembledBodies, making it easier to work with assembled robot data without needing to interact directly with the lower-level assembly implementation.

Parameters:: assembled_robots – The AssembledBodies instance containing the robot assembly data.

property attach_path: str#

Prim path of the floating (attach) body

Returns:: Prim path of the floating (attach) body.

property base_path: str#

Prim path of the base body

Returns:: Prim path of the base body.

property collision_mask: pxr.Usd.Relationship#

A Usd Relationship masking collisions between the two assembled robots

Returns:: A Usd Relationship masking collisions between the two assembled robots.

property fixed_joint: pxr.UsdPhysics.FixedJoint#

USD fixed joint linking base and floating body together

Returns:: USD fixed joint linking base and floating body together.

property root_joints: List[pxr.UsdPhysics.Joint]#

Root joints that tie the floating body to the USD stage. These are disabled in an assembled body, and will be re-enabled by the disassemble() function.

Returns:: Root joints that tie the floating body to the USD stage.

class AssembledBodies( base_path: str, attach_path: str, fixed_joint: pxr.UsdPhysics.FixedJoint, root_joints: List[pxr.UsdPhysics.Joint], attach_body_articulation_root: pxr.Usd.Prim, collision_mask=None, )#

Bases: object

Class representing two assembled rigid bodies connected by a fixed joint.

This class maintains references to the base and attach bodies, the fixed joint connecting them, and provides methods to manipulate their relative transform.

Parameters:

base_path – Prim path of the base body.
attach_path – Prim path of the attach body.
fixed_joint – Fixed joint connecting the bodies.
root_joints – Root joints of the attach body.
attach_body_articulation_root – Articulation root of attach body.
collision_mask – Collision mask between bodies.

Initialize an AssembledBodies instance.

Parameters:

base_path (str) – Prim path of the base body
attach_path (str) – Prim path of the attach body
fixed_joint (UsdPhysics.FixedJoint) – Fixed joint connecting the bodies
root_joints (List[UsdPhysics.Joint]) – Root joints of the attach body
attach_body_articulation_root (Usd.Prim) – Articulation root of attach body
collision_mask (Optional[Usd.Relationship]) – Collision mask between bodies

property attach_body_articulation_root: pxr.Usd.Prim#

USD articulation root of the floating body.

Returns:: USD articulation root of the floating body.

property attach_path: str#

Prim path of the floating (attach) body.

Returns:: Prim path of the floating (attach) body.

property base_path: str#

Prim path of the base body.

Returns:: Prim path of the base body.

property collision_mask: pxr.Usd.Relationship#

A Usd Relationship masking collisions between the two assembled bodies.

Returns:: A Usd Relationship masking collisions between the two assembled bodies.

property fixed_joint: pxr.UsdPhysics.FixedJoint#

USD fixed joint linking base and floating body together.

Returns:: USD fixed joint linking base and floating body together.

property root_joints: List[pxr.UsdPhysics.Joint]#

Root joints that tie the floating body to the USD stage. These are disabled in an assembled body,: and will be re-enabled by the disassemble() function.

Returns:: Root joints that tie the floating body to the USD stage.