AutoTileGen 1.0 for Mac was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. This software for Mac OS X is an intellectual property of Pixelatto. The software lies within Games, more precisely Tools. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe.
From the developer:
AutoTileGen is an automatic tileset generator for 2D game terrains. With three basic input tiles, the program generates a complete tileset (48 tiles) for you to use in your games. The features include slopes, normal map generation, a free autotiling plugin (AutoTileSet) and more.
You may want to check out more software for Mac, such as Quiz Builder, Nostromo Array or rpgng, which might be related to AutoTileGen.