From #openttdcoop wiki
OpenTTD can be downloaded freely from the OpenTTD.org homepage and as of version 1.0.0 the game no longer requires the original proprietary graphics files from TTD (Wikipedia:Transport Tycoon Deluxe) in order to run (though these can still be used). Instead OpenTTD will prompt you to acquire the OpenGFX files.
OpenTTD comes in a variety of versions. OpenTTD.org will at any point have up to three available; Stable, Nightly and occasionally Testing. There are also many other versions floating around, composed of various user patches, such as Infrastructure Sharing 2 and CargoDist
At #openttdcoop we use the nightlies, though not always the latest, which consist of a development snapshot each night (hence the name) with the latest features (and bugs) added into them. The currently used nightly is kept up to date in the channel topic. To get the correct version to join our servers use the IRC command
!download <your operating system of choice> Valid options are: lin, lin64, osx, win32, win64, or win9x as well as some helpful tool links (use !download by itself for a full list)
in chat and it will provide a download link for the corresponding version that is currently in use on that server.
Managing Multiple Versions
With so many version it can sometime be difficult to keep track of what's where, the key to keeping track of everything, is having a sensible directory structure to manage them in. (Examples in this section will be Windows based)
Suggested File Structure
First set up a base for everything OpenTTD install related.
Under this you can create sub-directories for each install
e.g. C:\OpenTTD\Stable\ C:\OpenTTD\Coop\ C:\OpenTTD\Nightly\
OpenTTD uses a central user directory to store its global configs and data files, which are used if these aren't found in it's local directory.
Where this is depends on your OS:
- 98/XP - C:\Documents and Settings\ %USERNAME% \My Documents\OpenTTD\
- Vista/7 - C:\Users\ %USERNAME% \My Documents\OpenTTD
(in W7 this may change if you've customised your libraries)
- *nix - ~/.openttd/ ( /home/ %USERNAME% /.openttd/ )
In this global directory will be the default 'data', 'content_download', 'save' and 'scenario' directories, along with default openttd.cfg and hs.dat.
To save space and to ease management, you can load your original/base GRF files into this global data directory.
To make each install work independently (i.e. not use the globals) you need to place an openttd.cfg file into the subdirectory
This file may be a blank file, and will make OpenTTD use assets relative to this config
i.e. C:\OpenTTD\Coop\data C:\OpenTTD\Coop\content_download etc.
If OpenTTD cannot find files in these it will attempt to find them in the global directory, before flagging an error.