Vertex

Vertices are points on a map at which two or more linedefs are joined. They have no properties other than their position. No two vertices may be coincident. Extra vertices are generated in the process of nodebuilding, but these are normally hidden from the user when the map is opened in a map editor.

Specification

The vertices of a map are stored in the VERTEXES lump as a list. Each vertex has a 4-byte entry consisting of the following:

Bytes	Data type	Description
0–1	Signed 16-bit integer	X position
2–3	Signed 16-bit integer	Y position

Since the positions are stored as signed 16-bit integers, they can range from -32768 to 32767.