Medit binary#

.meshb read + write lazy: binary only

Summary of the specification#

.meshb is the binary form of the INRIA Medit mesh format. The file is a stream of keyword-indexed fields: an integer keyword code, the byte position of the next field, then that field’s data. Codes identify the version and dimension first, then typed entity blocks — Vertices, Edges, Triangles, Quadrilaterals, Tetrahedra, Hexahedra — each a count followed by fixed-width records of node indices plus a trailing reference (tag) integer. The version code fixes whether floats are 32- or 64-bit.

Specification at a glance#

layout	keyword code, next-field offset, then the field payload
header codes	MeshVersionFormatted, Dimension
entity blocks	Vertices, Edges, Triangles, Quadrilaterals, Tetrahedra, Hexahedra
record shape	node indices (1-based) + one reference integer
float width	set by the version code: 32-bit or 64-bit
ascii sibling	.mesh — the same keywords in text form

Read the full Medit binary specification ↗

Reading#

import polyxios as px

mesh = px.read("model.meshb")
mesh.vertices          # (n, 3)
mesh.element_types     # element groups found in the file

Binary bodies can be memory-mapped instead of loaded:

mesh = px.read("big.meshb", lazy=True)

Writing#

px.write(mesh, "out.meshb")

This codec takes no format-specific options.

Quirks worth knowing#

The trailing reference integer on each entity becomes an element tag, which is how Medit files carry surface and region labels.
Field offsets are validated against the file size before allocation, so a truncated or hostile file raises instead of over-allocating.
Binary bodies can be memory-mapped with lazy=True.