blenderproc.python.types.URDFUtility module

All URDF objects are captured in this class.

class blenderproc.python.types.URDFUtility.URDFObject(armature, links, xml_tree=None)

Bases: Entity

This class represents an URDF object, which is comprised of an armature and one or multiple links. Among others, it serves as an interface for manipulation of the URDF model.

_set_fk_ik_mode(mode='fk')

Sets the mode of the bone chain.

Parameters:

mode (str) – One of “fk” or “ik” for forward / inverse kinematic.

_set_ik_bone_constraint(bone)

Sets the ik bone constraint.

Parameters:

bone (PoseBone) – Bone to set as ik constraint bone.

_set_ik_bone_controller(bone)

Sets the ik bone controller.

Parameters:

bone (PoseBone) – Bone to set as ik control bone.

_set_ik_bone_offset(offset)

Sets the location offset between the control and constraint bone.

Parameters:

offset (Matrix) – The location offset.

_set_ik_link(ik_link)

Sets the ik link constraint.

Parameters:

ik_link (Optional[Link]) – Link to set as ik link.

_set_keyframe(name, frame=0)

Sets a keyframe for a specific name for all bones of all links, as well as the copy_rotation constraint for

revolute joints.

Parameters:

• name (str) – Name of the keyframe to be inserted.

• frame (int) – Where to insert the keyframe.

_switch_fk_ik_mode(mode='fk', keep_pose=True)

Switches between forward and inverse kinematics mode. Will do this automatically when switching between e.g.

set_rotation_euler_fk() and set_rotation_euler_ik().

Parameters:

• mode (str) – One of for forward / inverse kinematik.

• keep_pose (bool) – If specified, will keep the pose when switching modes. Otherwise, will return to the old pose of the previously selected mode.

create_ik_bone_controller(link=None, relative_location=None, use_rotation=True, chain_length=0)

Creates an ik bone controller and a corresponding constraint bone for the respective link.

Parameters:

• link (Optional[Link]) – The link to create an ik bone for. If None, will use the last link.

• relative_location (Union[List[float], Vector, None]) – Relative location of the ik bone controller w.r.t. the bone’s location. This can be used to shift the point of control further away from the end effector.

• use_rotation (bool) – Whether to rotate the child links as well. Defaults to True.

• chain_length (int) – The number of parent links which are influenced by this ik bone. Defaults to 0 for all parents.

get_all_collision_local2world_mats()

Returns all transformations from the world frame to the collision objects.

Return type:

array

Returns:

Numpy array of shape (num_bones, 4, 4).

get_all_collision_objs()

Returns a list of all collision objects.

Return type:

List[MeshObject]

Returns:

List of all collision objects.

get_all_inertial_local2world_mats()

Returns all transformations from the world frame to the inertial objects.

Return type:

array

Returns:

Numpy array of shape (num_bones, 4, 4).

get_all_inertial_objs()

Returns a list of all inertial objects.

Return type:

List[Inertial]

Returns:

List of all inertial objects.

get_all_local2world_mats()

Returns all matrix_world matrices from every joint.

Return type:

array

Returns:

Numpy array of shape (num_bones, 4, 4).

get_all_urdf_objs()

Returns a list of all urdf-related objects.

Return type:

List[Union[Link, Inertial, MeshObject]]

Returns:

List of all urdf-related objects.

get_all_visual_local2world_mats()

Returns all transformations from world frame to the visual objects.

Return type:

array

Returns:

Numpy array of shape (num_bones, 4, 4).

get_all_visual_objs()

Returns a list of all visual objects.

Return type:

List[MeshObject]

Returns:

List of all visual objects.

get_links_with_revolute_joints()

Returns all revolute joints.

Return type:

List[Link]

Returns:

List of revolute joints.

has_reached_ik_pose(location_error=0.01, rotation_error=0.01)

Checks whether the urdf object was able to move to the currently set pose.

Parameters:

• location_error (float) – Tolerable location error in m.

• rotation_error (float) – Tolerable rotation error in radians.

Return type:

bool

Returns:

True if the link is at the desired ik pose; else False.

hide(hide_object=True)

Sets the visibility of the object.

Parameters:

hide_object (bool) – Determines whether the object should be hidden in rendering.

hide_links_and_collision_inertial_objs()

Hides links and their respective collision and inertial objects from rendering.

remove_link_by_index(index=0)

Removes a link and all its associated objects given an index. Also handles relationship of the link’s child

with its parent. This is useful for removing a ‘world link’ which could be a simple flat surface, or if someone wants to shorten the whole urdf object.

Parameters:

index (int) – Index of the joint to be removed.

set_ascending_category_ids(category_ids=None)

Sets semantic categories to the links and their associated objects.

Parameters:

category_ids (Optional[List[int]]) – List of ‘category_id’s for every link. If None, will create a list from [1 … len(links)].

set_location_ik(location, frame=0)

Performs location change in inverse kinematics mode.

Parameters:

• location (Union[List[float], array, Vector]) – Location vector.

• frame (int) – The keyframe where to insert the rotation.

set_rotation_euler_fk(link, rotation_euler, mode='absolute', frame=0)

Rotates one specific link or all links based on euler angles in forward kinematic mode. Validates values

with given constraints.

Parameters:

• link (Optional[Link]) – The link to be rotated. If None, will perform the rotation on all revolute joints.

• rotation_euler (Union[float, List[float], Euler, ndarray]) – The amount of rotation (in radians). Either three floats for x, y and z axes, or a single float. In the latter case, the axis of rotation is derived based on the rotation constraint. If these are not properly set (i.e., two axes must have equal min/max values) an exception will be thrown.

• mode (str) – One of [“absolute”, “relative”]. For absolute rotations we clip the rotation value based on the constraints. For relative we don’t - this will result in inverse motion after the constraint’s limits have been reached.

• frame (int) – The keyframe where to insert the rotation.

set_rotation_euler_ik(rotation_euler, mode='absolute', frame=0)

Performs rotation in inverse kinematics mode.

Parameters:

• rotation_euler (Union[float, List[float], Euler, ndarray]) – The amount of rotation (in radians). Either three floats for x, y and z axes, or a single float. In the latter case, the axis of rotation is derived based on the rotation constraint. If these are not properly set (i.e., two axes must have equal min/max values) an exception will be thrown.

• mode (str) – One of [“absolute”, “relative”]. For absolute rotations we clip the rotation value based on the constraints. For relative we don’t - this will result in inverse motion after the constraint’s limits have been reached.

• frame (int) – The keyframe where to insert the rotation.