Python (2.7-3.*) library for loading and utilizing triangular meshes.

• Import binary/ASCII STL, Wavefront, and OFF
• Import formats using assimp (if pyassimp installed)
• Import STEP files as meshes (if STEPtools Inc. Author Tools installed)
• Import 2D or 3D vector paths from DXF or SVG files
• Export meshes as binary STL, COLLADA, or OFF
• Preview meshes (requires pyglet)
• Fast loading of binary and ASCII STL files (on 234,230 face mesh, was 24.5x faster than assimp)
• Calculate face adjacencies quickly (for the same 234,230 face mesh .248 s)
• Calculate cross sections (.146 s)
• Split mesh based on face connectivity using networkx (4.96 s) or graph-tool (.584 s)
• Calculate mass properties, including volume, center of mass, and moment of inertia (.246 s)
• Find coplanar groups of faces (.454 s)
• Fix triangle winding to be consistent
• Fix normals to be oriented 'outwards' using ray tests
• Find convex hulls of meshes (.21 s)
• Compute a rotation/translation/tessellation invariant identifier for meshes (from an FFT of the radius distribution)
• Merge duplicate meshes from identifier
• Determine if a mesh is watertight (manifold)
• Repair single triangle and single quad holes
• Uniformly sample the surface of a mesh
• Find ray-mesh intersections
• Voxelize watertight meshes
• Unit conversions
• Create meshes by extruding 2D profiles
• Numerous utility functions, such as transforming points, unitizing vectors, grouping rows, etc.

The easiest way to install is:

sudo pip install git+https://github.com/mikedh/trimesh.git

If you would like to use ray queries or some path functionality, install dependencies:

sudo pip install shapely git+https://github.com/Toblerity/rtree.git svg.path 

To get the latest version of assimp/pyassimp from github:

sudo pip install git+https://github.com/robotics/assimp_latest.git 

Rtree may not build without libspatialindex installed, get it with:

sudo apt-get install libspatialindex* 

If you would like to use the trimesh.creation functions, meshpy is required:

sudo pip install meshpy

import numpy as np
import trimesh

# this list will be much longer if assimp is available
print(trimesh.available_formats())

# load_mesh can accept a filename or file object, 
# however file objects require 'file_type' specified (eg. file_type='stl')
# on load does basic cleanup of mesh, including merging vertices 
# and removing duplicate/degenerate faces
mesh = trimesh.load_mesh('./models/unit_cube.STL')

# split mesh based on connected components
# by default this will only return watertight meshes, but the check can be disabled
meshes = mesh.split() 

# first component  
m = meshes[0]

# assign all faces a color
m.set_face_colors()

# find groups of coplanar adjacent faces
facets, facets_area = m.facets(return_area=True)

# the largest group of faces by area    
largest_facet = facets[np.argmax(facets_area)]

# set all faces of the largest facet to a random color
m.faces[largest_facet] = trimesh.color.random_color()

# preview mesh in an opengl window
m.show()

In the mesh view window, dragging rotates the view, ctl + drag pans, mouse wheel scrolls, 'z' returns to the base view, 'w' toggles wireframe mode, and 'c' toggles backface culling (useful if viewing non-watertight meshes).