Mesh Formats¶

There’s lots of mesh formats out there!

Which Mesh Format Should I Use?¶

Quick recommendation: GLB. If you’re looking for “the simplest possible ASCII format because I have to write an importer in another language” you should take a look at OFF.

GLTF is nice because it has a well defined specification, supports most things people would want, and is very fast to load. It’s fast because the format has a small JSON header which defines the layout of a packed binary blob, so the arrays can be loaded with numpy.frombuffer which is extremely fast. As a counterpoint a format like 3MF defines each vertex as an <vertex><x>"1.0123312"</x> ..., which is almost as far from fast as it is possible to get.

A very popular format is Wavefront OBJ. It’s supported across many tools, although it lacks a specification and has an internal data structure that requires some pretty heavy conversion to the trimesh flat-array format which can lead to some confusion: for example f 1/2/3 4/5/6 7//7 9/9/9 is a valid face. It’s not a bad choice, but going with GLB is probably advisable in most cases.

Supported Formats¶

No dependencies indicates a minimal install of just trimesh and numpy can load the format. If you are working with the textures, images are handled using pip install pillow.

Format	Dependencies	Notes
`GLB`/`GLTF`		A scene format with flat arrays (i.e. very quick loading), wide support, and a well defined specification. Most people should use this is possible. It also supports most things you’d want including texture, point clouds, etc.
`STL`		Has both ASCII and binary representations, both of which are supported. This is a very basic format, and it consists of a “triangle soup” with no shared vertices. This format is the reason why `trimesh` has the default `process=True` which merges vertices since an unindexed triangle soup isn’t super useful.
`PLY`		Has both ASCII and Binary representations, both are supported. It has indexed triangles, and a header format that supports named properties. Overview
`OBJ`		Wavefront OBJ, relatively slow to parse and may require re-indexing to match the `trimesh` “matching arrays” data structure.
`OFF`		Text format that is just vertices and faces in ASCII
`3MF`	`lxml`, `networkx`	An XML based 3D printing focused mesh format. It
`3DXML`	`lxml`, `networkx`, `PIL`	Dassault’s XML format from CATIA/SolidWorks, the easiest way to get from Solidworks to a nice 3D scene.
`DAE`/`ZAE`	`lxml`, `PIL`, `pycollada`	COLLADA, an XML-based scene format that supports everything.
`STEP`/`STP`	`cascadio`	The only boundary representation format with open-source loaders available. `cascadio` uses OpenCASCADE to convert to GLB before loading.
`XAML`	`lxml`	Microsoft’s 3D XAML format which exports from Solidworks
`DXF`		AutoCAD’s drawing format, we only support the ASCII version with 2D geometry.
`SVG`	`svg.path`	We import 2D paths as `trimesh.Path2D` from these, discarding pretty much all visual information other than the curves.
`XYZ`		Simple ASCII point cloud format with just one coordinate per line.