FreeSurfer Surface file format

This article is a brief translation of http://www.grahamwideman.com/gw/brain/fs/surfacefileformats.htm, because I am not a word-for-word translation, but rather take some sentences which I think are of greater use to paraphrase.
Overview: Volumes and Surfaces
Generally speaking, the FreeSurfer program mainly deals with two kinds of data. One is the volume data based on Voxel, and the second is the surface data from volume.
Surface data consists of a series of vertices, including the position of vertices in space, and polygons (usually triangles, sometimes quads).

vertex and polygon slices
The vertices of surface data are often subjected to various transformations. So their position is constantly changing, in order to trace these vertices, FreeSurfer assigns an ID to each vertex or "vertex number". Thereafter, data from other data items is mapped to the corresponding vertices by vertex numbers. So, regardless of the vertex's coordinate position, you can track the vertex position by vertex number.

Patches are part of surface and contain only a subset of vertices, but the vertex numbers are consistent.

motivation for this page
To manipulate and manipulate data, you need a clear understanding of the conceptual framework of the data and the storage structure. The mind forms an approximate model.
In order to obtain this clear model, this page tries to explain the data format of the various files used by FreeSurfer.

I think that the general understanding of my previous translation of the content is enough for normal use; recently busy, translated to this, want to know the specific file data format for the content, you can go to the original site to look at the beginning.