A special Source 2013 mod that helps HL2 level designers make better maps and have a more comfortable experience designing them without changing too much of the game itself. Mapbase includes 50+ new entities (not counting filters or engine ports), hundreds of new I/O/KV (Inputs/Outputs/Keyvalues), heavily reworked FGDs, and a few big surprises. Mappers would create their maps based off of this mod and larger mods with their own unique changes would draw from Mapbase's code and assets.
The main Mapbase trailer released in July.
YouTube link: Youtube.com