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Import, export, process, analyze and view triangular meshes.

Project description

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Python (2.7-3.*) library for loading and utilizing triangular meshes. The goal of the library is to provide a fully featured Trimesh object which allows for easy manipulation and analysis, in the style of the excellent Polygon object in the Shapely library.

The API is mostly stable, but this should not be relied on and is not guaranteed; install a specific version if you plan on deploying something using trimesh as a backend.


  • Import binary/ASCII STL, Wavefront, OFF, and PLY
  • 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)
  • Internal caching of computed values which are automatically cleared when vertices or faces are changed
  • 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
  • Calculate whether or not a point lies inside a watertight mesh 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
  • Boolean operations on meshes (intersection, union, difference) if OpenSCAD is installed
  • 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 trimesh

Optional Dependencies

Basic functionality is available immediately. Some functions (ray queries, polygon handling, mesh creation, viewer windows, boolean operations, additional importers) require additional libraries:

$ sudo apt-get install cmake openscad blender libspatialindex-dev
$ sudo pip install pyglet shapely git+ git+ svg.path meshpy

Quick Start

Here is an example of loading a mesh from file and colorizing its faces.

import numpy as np
import trimesh

# load a file by name or from a buffer
mesh = trimesh.load_mesh('./models/featuretype.STL')

# is the current mesh watertight?

# what's the euler number for the mesh?

# lets get a convex hull of the mesh
hull = mesh.convex_hull

# 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?

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

# set each facet to a random color
for facet in facets:
    mesh.visual.face_colors[facet] = trimesh.visual.random_color()

# preview mesh in an opengl window if you installed pyglet with pip

# transform method can be passed a (4,4) matrix and will cleanly apply the transform

# a minimum volume oriented bounding box is available

# show the mesh overlayed with its oriented bounding box
# the bounding box is a trimesh.primitives.Box object, which subclasses
# Trimesh and lazily evaluates to fill in vertices and faces when requested
# (press w in viewer to see triangles)
(mesh + mesh.bounding_box_oriented).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.

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