Quick Start

A simple example showing various properties of Trimesh objects.

import numpy as np

import trimesh

# load a file by name or from a buffer
mesh = trimesh.load_mesh("../models/featuretype.STL")
# to keep the raw data intact, disable any automatic processing
# mesh = trimesh.load_mesh('../models/featuretype.STL', process=False)

# is the current mesh watertight?
mesh.is_watertight

True

# what's the euler number for the mesh?
mesh.euler_number

-16

# the convex hull is another Trimesh object that is available as a property
# lets compare the volume of our mesh with the volume of its convex hull
np.divide(mesh.volume, mesh.convex_hull.volume)

np.float64(0.7792407744466933)

# since the mesh is watertight, it means there is a
# volumetric center of mass which we can set as the origin for our mesh
mesh.vertices -= mesh.center_mass

# what's the moment of inertia for the mesh?
mesh.moment_inertia

array([[ 6.93059627e+00, -1.43877613e-03, -1.49424850e-01],
       [-1.43877613e-03,  2.19191960e+01, -1.25194047e-04],
       [-1.49424850e-01, -1.25194047e-04,  2.62344872e+01]])

# if there are multiple bodies in the mesh we can split the mesh by
# connected components of face adjacency
# since this example mesh is a single watertight body we get a list of one mesh
mesh.split()

[<trimesh.Trimesh(vertices.shape=(1722, 3), faces.shape=(3476, 3), name=`featuretype.STL`)>]

# preview mesh in a pyglet window from a terminal, or inline in a notebook
mesh.show()

# facets are groups of coplanar adjacent faces
# set each facet to a random color
# colors are 8 bit RGBA by default (n,4) np.uint8
for facet in mesh.facets:
    mesh.visual.face_colors[facet] = trimesh.visual.random_color()

# transform method can be passed a (4,4) matrix and will cleanly apply the transform
mesh.apply_transform(trimesh.transformations.random_rotation_matrix())

<trimesh.Trimesh(vertices.shape=(1722, 3), faces.shape=(3476, 3), name=`featuretype.STL`)>

# an axis aligned bounding box is available
mesh.bounding_box.primitive.extents

TrackedArray([2.99689534, 4.13012379, 5.22924913])

# a minimum volume oriented bounding box is available
mesh.bounding_box_oriented.primitive.extents

TrackedArray([1.375, 2.5  , 5.   ])

mesh.bounding_box_oriented.primitive.transform

TrackedArray([[ 0.6390169 ,  0.76395662,  0.08959738,  0.09207914],
              [ 0.68755498, -0.61953012,  0.3787487 ,  0.10119852],
              [ 0.34485585, -0.18042369, -0.92115239,  0.04205169],
              [ 0.        ,  0.        ,  0.        ,  1.        ]])

# the bounding box is a trimesh.primitives.Box object, which subclasses
# Trimesh and lazily evaluates to fill in vertices and faces when requested
mesh.bounding_box_oriented.show()

# bounding spheres and bounding cylinders of meshes are also
# available, and will be the minimum volume version of each
# except in certain degenerate cases, where they will be no worse
# than a least squares fit version of the primitive.
(
    mesh.bounding_box_oriented.volume,
    mesh.bounding_cylinder.volume,
    mesh.bounding_sphere.volume,
)

(17.18750000000001, np.float64(33.80590668210305), 95.89438997522058)