Lazy loading#

For large meshes (gigabytes of binary data), pass lazy=True. polyxios memory-maps the file and only loads the pages you actually touch - the rest stays on disk until needed.

# File is opened but data is not loaded into RAM yet
mesh = px.read("huge_brain.vtk", lazy=True)

# Only the vertices are pulled from disk here
first_vertex = mesh.vertices[0]

# Element connectivity is still on disk until you access it

lazy=True is honoured for binary .vtk, .ply and .stl files. ASCII formats load eagerly (the whole file must be parsed to extract values). Binary STL lazy mode skips vertex deduplication - vertices are returned as-is (3 per triangle), avoiding the extra pass over the data. .meshb needs no flag: a path is always memory-mapped and a file object always read into memory, so lazy=True there warns and changes nothing.