Contains area 3D data, including:

• Terrain geometry
• Water geometry
• Grass
• Textures
• If the file is a TRN file:
  • Walkmesh geometry, identical to terrain geometry
• If the file is a baked TRX file:
  
  • Walkmesh geometry, modified by placeable walkmeshes and walkmesh cutters
  • Pathfinding pre-calculated data

File format

The TRN file format is quite similar to MDB format.

Header struct (12 bytes)

PacketKeyTable struct (8 bytes)

Packet struct (variable length)

Each packet contains different data depending on their type

Packet types

There are 3 types of packets:

• TRWH: Terrain Width Height info

• TRRN: Terrain geometry info

• ASWM: Walkmesh geometry & pathfinding data

• WATR: Water geometry info

Source: https://neverwintervault.org/project/nwn2/other/trn-fileformat