Sub-sectors are to segs what sectors are to linedefs; they are the 'space' between segs. The most relevant information on them can be found on the NODES page. A subsector with X segs starting at Y will have the lowest numbered seg at Y and the highest numbered seg at Y + X. The segs in ssector 0 should start with seg 0 through Y, ie 0, 1, ... , Y - 1, Y. Sub-sector 1 will have segs starting at Y and going to Y + 1, Y + 2, ... Z - 1, Z where Z is the total number of segs (for ssector 1) + Y.
|0-1||Short||Number of segments in this sub-sector|
|2-3||Short||First segment in this sub-Sector|