Binary Mesh Format

This is a small python library implementation for reading and writing triangulated meshes.

Usage

import binarymeshformat as bmf

meshTracks = bmf.loadMeshes(filename)

That will return a list of mesh tracks.

Track structure

A track has a name and a map. The name is just a string and the map maps integers to meshes.

Mesh structure

The mesh contains points in 3D space and their connections. It uses 3 aspects:

• positions which is an array of x,y,z coordinates.
• connections which is an array of indexes indicating two points are connected. Two indexes per connection.
• triangles an array of indexes, three indexes per triangle.

File Format

A .bmf file contains mesh tracks, where a track is a collection of meshes over time, a mesh is a set positions, connections, and triangles.

Header

The first four bytes are a version string. The current version string should be -1.

The next four bytes are an integer that says how many tracks are in the file.

Track

The first data in a track is a name, which can be a variable size. The first two bytes indicate the length of the name. The string encoding is a subset of UTF8.

Then each mesh is written.

Mesh

First a 4 byte int to represent the timepoint the mesh exists at.

Then a 4 byte integer representing the number of positions values, 8 byte float. Then a 4 byte integer is use to represent the number of connections indexes, each connection index is a 4 byte integers. Finally a 4 byte integer is used to represent the number of triangle indexes, each index is a 4 byte integer