Object Model

Base class for all objects.

We use Mujoco Objects to implement all objects that:

1. may appear for multiple times in a task

2. can be swapped between different tasks

Typical methods return copy so the caller can all joints/attributes as wanted

Parameters

• obj_type (str) –

  Geom elements to generate / extract for this object. Must be one of:

  ’collision’

  Only collision geoms are returned (this corresponds to group 0 geoms)

  ’visual’

  Only visual geoms are returned (this corresponds to group 1 geoms)

  ’all’

  All geoms are returned

• duplicate_collision_geoms (bool) – If set, will guarantee that each collision geom has a visual geom copy

__init__(obj_type='all', duplicate_collision_geoms=True)

merge_assets(other)

Merges @other’s assets in a custom logic.

Parameters

other (MujocoXML or MujocoObject) – other xml file whose assets will be merged into this one

get_obj()

Returns the generated / extracted object, in XML ElementTree form.

Returns

Object in XML form.

Return type

ET.Element

exclude_from_prefixing(inp)

A function that should take in either an ET.Element or its attribute (str) and return either True or False, determining whether the corresponding name / str to @inp should have naming_prefix added to it. Must be defined by subclass.

Parameters

inp (ET.Element or str) – Element or its attribute to check for prefixing.

Returns

True if we should exclude the associated name(s) with @inp from being prefixed with naming_prefix

Return type

bool

_get_object_subtree()

Returns a ET.Element It is a <body/> subtree that defines all collision and / or visualization related fields of this object. Return should be a copy. Must be defined by subclass.

Returns

body

Return type

ET.Element

_get_object_properties()

Helper function to extract relevant object properties (bodies, joints, contact/visual geoms, etc…) from this object’s XML tree. Assumes the self._obj attribute has already been filled.

property important_geoms

Returns: dict: (Default is no important geoms; i.e.: empty dict)

property important_sites

Returns: dict:

obj

Object default site

property important_sensors

Returns: dict: (Default is no sensors; i.e.: empty dict)

property get_site_attrib_template

Returns attribs of spherical site used to mark body origin

Returns

Dictionary of default site attributes

Return type

dict

property get_joint_attrib_template

Returns attribs of free joint

Returns

Dictionary of default joint attributes

Return type

dict

MujocoObjects that are loaded from xml files (by default, inherit all properties (e.g.: name) from MujocoObject class first!)

Parameters

• fname (str) – XML File path

• name (str) – Name of this MujocoXMLObject

• joints (None or str or list of dict) – each dictionary corresponds to a joint that will be created for this object. The dictionary should specify the joint attributes (type, pos, etc.) according to the MuJoCo xml specification. If “default”, a single free-joint will be automatically generated. If None, no joints will be created.

• obj_type (str) –

  Geom elements to generate / extract for this object. Must be one of:

  ’collision’

  Only collision geoms are returned (this corresponds to group 0 geoms)

  ’visual’

  Only visual geoms are returned (this corresponds to group 1 geoms)

  ’all’

  All geoms are returned

• duplicate_collision_geoms (bool) – If set, will guarantee that each collision geom has a visual geom copy

__init__(fname, name, joints='default', obj_type='all', duplicate_collision_geoms=True)

static _duplicate_visual_from_collision(element)

Helper function to duplicate a geom element to be a visual element. Namely, this corresponds to the following attribute requirements: group=1, conaffinity/contype=0, no mass, name appended with “_visual”

Parameters

element (ET.Element) – element to duplicate as a visual geom

Returns

duplicated element

Return type

element (ET.Element)

_get_geoms(root, _parent=None)

Helper function to recursively search through element tree starting at @root and returns a list of (parent, child) tuples where the child is a geom element

Parameters

• root (ET.Element) – Root of xml element tree to start recursively searching through

• _parent (ET.Element) – Parent of the root element tree. Should not be used externally; only set during the recursive call

Returns

array of (parent, child) tuples where the child element is a geom type

Return type

list

Base class for all procedurally generated objects.

Parameters

• obj_type (str) –

  Geom elements to generate / extract for this object. Must be one of:

  ’collision’

  Only collision geoms are returned (this corresponds to group 0 geoms)

  ’visual’

  Only visual geoms are returned (this corresponds to group 1 geoms)

  ’all’

  All geoms are returned

• duplicate_collision_geoms (bool) – If set, will guarantee that each collision geom has a visual geom copy

__init__(obj_type='all', duplicate_collision_geoms=True)

sanity_check()

Checks if data provided makes sense. Called in __init__() For subclasses to inherit from

static get_collision_attrib_template()

Generates template with collision attributes for a given geom

Returns

Initial template with ‘pos’ and ‘group’ already specified

Return type

dict

static get_visual_attrib_template()

Generates template with visual attributes for a given geom

Returns

Initial template with ‘conaffinity’, ‘contype’, and ‘group’ already specified

Return type

dict

append_material(material)

Adds a new texture / material combination to the assets subtree of this XML Input is expected to be a CustomMaterial object

See http://www.mujoco.org/book/XMLreference.html#asset for specific details on attributes expected for Mujoco texture / material tags, respectively

Note that the “file” attribute for the “texture” tag should be specified relative to the textures directory located in robosuite/models/assets/textures/

Parameters

material (CustomMaterial) – Material to add to this object