Creating New Campaign Map in Rome Remastered

The underlying map structure in Total War: Rome Remastered is exactly the same as for the original game and can still be changed via text file and tga image alterations, however, the visual element of the campaign map is now provided by a separate 3D mesh and textures.

Mapping Components

Any base map that loads under RTW should load under RR including using the same map.rwm. For general advice on making a Rome Total War map see the Mapping Index.

map_heights.hgt

You don't need to use a .hgt file the game will generate a map.rwm from just map_heights.tga. However, if your map is the same size as the vanilla map in data/world/maps/base - then you either need your own .hgt file, or you will have to delete the base games' .hgt file - otherwise the game will just use that information instead of your map_heights.tga

Mesh Components

Mesh Pieces

The mesh is formed from .cas pieces found in:

data\terrain\campaign\pieces

the mesh pieces should be rectangular and all at the same size.

These mesh pieces are not automatically generated by the game so will not correspond with any changes made to the mapping .tga files.

Currently, RTW/BI seems to require 104x files listed in descr_map_tiles.txt, however, these can be duplicated files moved somewhere away from the visible map area.

Heightmap bins

The game generates .bin files based on the height information in the mesh piece .cas files. The data in the .bin files is for height points only no x,y coordinates are given. This data is used to set the height of settlement, tree and resource models on the campaign map, and to set the 'ground level' that armies and agents stand on.

Using a data\terrain\campaign\descr_map_tiles.txt file with differently named .cas and .bin files requested than in the original game will trigger the game to write new .bin files, if these files don't already exist in the mod-folder they will be written in:
DATA\terrain\campaign\heightmap
That's the main game data folder not the mod-folder, cut and paste them from there to your mod-folder! Cut, because if they overwrote your original game files, you will need to let the vanilla game recreate them based on the correct map.

Ideally, name your new piece .cas files differently from the vanilla ones to avoid any accidental overwriting.