Multi-Tool for the time being is like a shorcut holder with some added features like customConfig and the VPK creator. In the future you will be able to create mods using it just like you could with the old SDK launcher.

Games that have their own authoring tool set like Portal 2, L4D2 and CSGO allow you to make maps and minor mods (through the use of vscripts and hammer logic) but you can't change any major code like say making a portal gun that fires four different portals.

If you are looking to make a full mod where you can change code and the like then SDK 2013[github.com] is what you are looking for. It has two branches one for multiplayer and one for singleplayer based on HL2 Deathmatch and HL2. Alien Swarm also provides full source code as well.

If you are new to the Source Engine I suggest starting out with either a small multiplayer or singleplayer map so you can learn the limits of the engine before you go and get yourself in over your head. Check out the tutorial tab on Multi-Tool for some tutorial links, I recommend TopHATTwaffle personally.

Sadly a lot of tutorials related to modding broke with Valves change from 2006/2007 branch to 2013 and the move to steampipe. So while there are good tutorials out there for starting mods they are not up to date, this is something I hope will be changed in the future.

If none of the download links work let me know!

Version#: 1.02
Download links
Google Drive download[drive.google.com]
Previous mirrors were removed due to fear of contamination, if mediafire isn't sufficient enough for you let me know of an alternate location that would be better for you.

Changelog:
* Added VPK creator
* Added Blade Symphony Support
* Added WIP Tutorials Tab
* Fixed Portal 2 not launching
* Fixed bug for user somehow not having a gameconfig.txt by default in sdk 2013 when using customConfig


* Updated customConfig setup
-* Removed unneeded options
-* Users have to include HL2 now (before if you didn't it messed up sdk 2013's hammer)
-* HL2 now mounts in front of everything else to ensure nothing breaks
-* EYE support added
-* Now creates a custom folder for mounting custom assets
-* Added a button to open the custom folder

Known Bugs:
* Korean users might have some issues due to a character conflict
* Users who are using a secondary drive for their steam games may need to download the beta version of the tools (look at the groups announcements page)

Could you type out the full file path for you Source SDK 2013 multiplayer folder? I need to know if it uses non English characters.

It looks like it might be an issue with my program not being able to read the characters correctly due to language settings. I'll see if there's a way I can fix this.

Can you post a picture of what the drop down list looks like for you? It should have listed any games you have installed.

Unzip the Source MultiTool folder anywhere you want, for example I have it on my desktop.

You might need administrator privileges to be able to use the program as it uses your systems registry keys to find where steam is located.

If you are still not seeing any games after that please use the debug tab and tell me what info it fills in when you press "Get Debug Info"

Version#: 1.01
Download links
File Dropper[www.filedropper.com]
DataFileHost[www.datafilehost.com]

Changelog:
Added model viewer support

http://gtm.steamproxy.vip/sharedfiles/filedetails/?id=198444877

DIMEDROLL の投稿を引用：

Nuclear Dawn is built on Left 4 Dead 2's engine branch afaik.

So this custom config is mostly meant for Garry's Mod mapping, am I right?

Not necessarily, I have a side project I work on from time to time that uses both CSS and my own content so I use custom Config for that along with my own fgd.

But yes it's mainly meant for Garry's Mod and Source mods in general.