trimesh.scene.transforms

class trimesh.scene.transforms.EnforcedForest

Bases: object

A simple forest graph data structure: every node is allowed to have exactly one parent. This makes traversal and implementation much simpler than a full graph data type; by storing only one parent reference, it enforces the structure for “free.”

__init__()

add_edge(u, v, **kwargs)

Add an edge to the forest cleanly.

Parameters

• u (any) – Hashable node key.

• v (any) – Hashable node key.

• kwargs (dict) – Stored as (u, v) edge data.

Returns

changed – Return if this operation changed anything.

Return type

bool

property children

Get the children of each node.

Returns

children – Keyed {node : [child, child, …]}

Return type

dict

property nodes

Get a set of every node.

Returns

nodes – Every node currently stored.

Return type

set

remove_node(u)

Remove a node from the forest.

Parameters

u (any) – Hashable node key.

Returns

changed – Return if this operation changed anything.

Return type

bool

shortest_path(u, v)

Find the shortest path between u and v, returning a path where the first element is always u and the last element is always v, disregarding edge direction.

Parameters

• u (any) – Hashable node key.

• v (any) – Hashable node key.

Returns

path – Path between u and v

Return type

(n,)

successors(node)

Get all nodes that are successors to specified node, including the specified node.

Parameters

node (any) – Hashable key for a node.

Returns

successors – Nodes that succeed specified node.

Return type

set

class trimesh.scene.transforms.SceneGraph(base_frame='world')

Bases: object

Hold data about positions and instances of geometry in a scene. This includes a forest (i.e. multi-root tree) of transforms and information on which node is the base frame, and which geometries are affiliated with which nodes.

__init__(base_frame='world')

Create a scene graph, holding homogeneous transformation matrices and instance information about geometry.

Parameters

base_frame (any) – The root node transforms will be positioned from.

clear()

copy()

Return a copy of the current TransformForest.

Returns

copied – Copy of current object.

Return type

TransformForest

from_edgelist(edges, strict=True)

Load transform data from an edge list into the current scene graph.

Parameters

• edgelist ((n,) tuples) – Keyed (node_a, node_b, {key: value})

• strict (bool) – If True raise a ValueError when a malformed edge is passed in a tuple.

property geometry_nodes

Which nodes have this geometry? Inverse of nodes_geometry.

Returns

geometry_nodes – Keyed {geometry_name : node name}

Return type

dict

get(frame_to, frame_from=None)

Get the transform from one frame to another.

Parameters

• frame_to (hashable) – Node name, usually a string (eg ‘mesh_0’)

• frame_from (hashable) – Node name, usually a string (eg ‘world’). If None it will be set to self.base_frame

Returns

transform – Homogeneous transformation matrix

Return type

(4, 4) float

Raises

ValueError – If the frames aren’t connected.

load(edgelist)

Load transform data from an edge list into the current scene graph.

Parameters

edgelist ((n,) tuples) – Structured (node_a, node_b, {key: value})

property nodes

A list of every node in the graph.

Returns

nodes – All node names.

Return type

(n,) array

property nodes_geometry

The nodes in the scene graph with geometry attached.

Returns

nodes_geometry – Node names which have geometry associated

Return type

(m,) array

remove_geometries(geometries)

Remove the reference for specified geometries from nodes without deleting the node.

Parameters

geometries (list or str) – Name of scene.geometry to dereference.

show(**kwargs)

Plot the scene graph using networkx.draw_networkx which uses matplotlib to display the graph.

Parameters

kwargs (dict) – Passed to networkx.draw_networkx

to_edgelist()

Export the current transforms as a list of edge tuples, with each tuple having the format: (node_a, node_b, {metadata})

Returns

edgelist – Of edge tuples

Return type

(n,) list

to_flattened()

Export the current transform graph with all transforms baked into world->instance.

Returns

flat – Keyed {node : {transform, geometry}

Return type

dict

to_gltf(scene, mesh_index=None)

Export a transforms as the ‘nodes’ section of the GLTF header dict.

Parameters

• scene (trimesh.Scene) – Scene with geometry.

• mesh_index (dict or None) – Mapping { key in scene.geometry : int }

Returns

gltf – With ‘nodes’ referencing a list of dicts

Return type

dict

to_networkx()

Return a networkx copy of this graph.

Returns

graph – Directed graph.

Return type

networkx.DiGraph

update(frame_to, frame_from=None, **kwargs)

Update a transform in the tree.

Parameters

• frame_from (hashable object) – Usually a string (eg ‘world’). If left as None it will be set to self.base_frame

• frame_to (hashable object) – Usually a string (eg ‘mesh_0’)

• matrix ((4,4) float) – Homogeneous transformation matrix

• quaternion ((4,) float) – Quaternion ordered [w, x, y, z]

• axis ((3,) float) – Axis of rotation

• angle (float) – Angle of rotation, in radians

• translation ((3,) float) – Distance to translate

• geometry (hashable) – Geometry object name, e.g. ‘mesh_0’

• extras (dictionary) – Optional metadata attached to the new frame (exports to glTF node ‘extras’).

trimesh.scene.transforms.kwargs_to_matrix(matrix=None, quaternion=None, translation=None, axis=None, angle=None, **kwargs)

Take multiple keyword arguments and parse them into a homogeneous transformation matrix.

Returns

matrix – Homogeneous transformation matrix.

Return type

(4, 4) float