Object Model

The MujocoObject class serves as a catch-all base class that is used to capture individual simulation objects to instantiate within a given simulation. This is done in one of two ways via extended classes – the MujocoXMLObject reads in information from a corresponding object XML file, whereas the MujocoGeneratedObject proecedurally generates a custom object using a suite of utility mj modeling functions. In conjunction with the RobotModel, and Arena classes, these classes serve as the basis for forming the higher level Task class which is used to ultimately generate the MjSim simulation object.

Base Object Model

class robosuite.models.objects.objects.MujocoObject(obj_type='all', duplicate_collision_geoms=True)

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

XML Object Model

class robosuite.models.objects.objects.MujocoXMLObject(fname, name, joints='default', obj_type='all', duplicate_collision_geoms=True)

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

Generated Object Model

class robosuite.models.objects.objects.MujocoGeneratedObject(obj_type='all', duplicate_collision_geoms=True)

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