Configuring Hammer For Dota 2
Configuring Alien Swarm SDK
Follow Steps 1 through 6 in Cyborgmatt's Model Viewer Guide
Download AlienSwarm SDK.
Go to SteamApps\Common\alien swarm\swarm\ and edit the gameinfo.txt. Add the game content you extracted to the search path (similar to step 6 in cyborgmatt's tutorial).
To properly build a Dota 2 map, you need the following tools:
Download both of these and extract them into the bin folder from above.
Open Hammer, and select Tools -> Options...
Select the 'Build Programs' tab. Make sure your configuration is Dota 2. For the 'BSP Executable', select the version of vbsp that you downloaded. You can blank the fields 'Game Executable', 'VIS executable', and 'RAD executable'. Select a good place to place compiled maps.
Create a new map. Select 'Run Map'. Hit 'Expert'. Create a new config 'Dota 2'. For the first command, we want to run BSP, so hit New, then 'cmds' and select 'BSP Program' and copy the BSP parameter line from default. Second command we want to run is 'UpVersion', so hit new 'New' then 'Cmds'. Select 'Executable' and find 'UpVersion.exe' in the directory you put it. Add '$path\$file.bsp' to the parameters. Finally, we want to copy the final .bsp file to the dota 2 maps directory, so hit New, then in Cmds select 'Copy File'. The params are '$path\$file.bsp "path\to\dota2\maps"'